Anchor App Phase 1 Part 2

Summary

Phase 1 Part 2 of the Anchor App: built a canvas pane that accepts image-file drops, supports full element manipulation (select/move/resize/delete) with undo/redo, persists to disk, and introduced the model–view split with multi-pane data sharing. Plus several engine additions. Ended at a natural pause before step 8 (embedded views) and Phase 1 Part 3 (text editing).

Session orientation:

Picked up from Phase 1 Part 1 (workspace shell, panes/slots/templates, drag-to-swap, modes, persistence).
User chose path B from the prior session's options: build one concrete pane type — a free-flowing canvas with external-source image drops — to test references-of-content questions and prepare for the model–view architecture work.
Decided to skip the cross-app drop deep-dive (custom Win32 OLE drop handler) after surfacing that SDL2's drop target only accepts CF_HDROP + CF_UNICODETEXT + CF_TEXT, which means browser/Discord drags showing custom Chromium/Mozilla formats get rejected with a stop-sign cursor. Workaround for now: save-to-disk then drag from Explorer.

Engine: drag-and-drop event capture (sub-step 1):

Added SDL_DROPFILE event handling to anchor.c's main SDL_PollEvent loop. Bounded queue (32 paths × 1024 chars) static-allocated; SDL allocates event.drop.file and we copy + SDL_free immediately. New Lua function engine_get_dropped_files() returned the queued paths and drained the queue (later renamed/refactored).
Sub-step 1.5 added SDL_DROPTEXT support alongside SDL_DROPFILE for the cross-app investigation. Refactored to unified drops[] table with DropKind enum (DROP_KIND_FILE / DROP_KIND_TEXT) and renamed Lua function to engine_get_drops() returning list of {kind='file'|'text', value='...'} tables.

Engine: cursor API:

Added engine_set_cursor(name) exposing SDL system cursors: 'arrow', 'ibeam', 'wait', 'crosshair', 'waitarrow', 'sizenwse', 'sizenesw', 'sizewe', 'sizens', 'sizeall', 'no', 'hand'. Cursors created lazily on first use and cached in a static array cursor_cache[SDL_NUM_SYSTEM_CURSORS] keyed by SDL_SystemCursor enum. Safe to call every frame — SDL no-ops if cursor unchanged.

Engine: focus-clickthrough:

Set SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH = "1" before SDL_Init so the first click on an unfocused window after returning from Explorer/another app passes through as a real click instead of being eaten by Windows just refocusing the window.

Engine: stencil clear on mask:

Added glClearStencil(0); glClear(GL_STENCIL_BUFFER_BIT); to the COMMAND_STENCIL_MASK case in anchor.c. Without this, sequential mask calls in a single frame accumulate (union of all rects) — two canvas panes each defining their own clip would let each pane's draws bleed into the other's rect.
Known limitation discovered but not fixed engine-side: the SDF rect fragment shader doesn't discard fully-transparent fragments, so stencil writes happen across the rect's 2-pixel AA padding, causing ~2-pixel stencil bleed past the requested rect. Worked around in canvas.lua by insetting the stencil mask shape by 2 pixels (SDF_PAD = 2).

Content store (content_store.lua):

File-content-addressed blob storage at app/data/blobs/<hex>.<ext>. FNV-1a 64-bit hash of file contents as identifier (placeholder; should be replaced by engine SHA-256 once Track B's HTTP client lands).
Opaque blob IDs (blob:<hex>.<ext>) — paths never leak into documents. Server-friendly: the same hash maps to a local file today and could map to https://a327ex.com/blobs/<hash>.<ext> on the future server with the resolver as the only thing that changes.
API: content_store_init() (idempotent mkdir), content_store_put(source_path) → blob_id, err (hash + copy, dedups by hash), content_store_path(blob_id), content_store_resolve(blob_id) → image.
Image extensions whitelist: png, jpg, jpeg, gif, webp, bmp.

Canvas pane initial implementation (sub-step 2):

app/panes/canvas.lua — element list with {type='image', blob_id, image, x, y, w, h} shape.
Initial drop position centered at cursor, native pixel size on drop (later changed; first version had MAX_INITIAL_SIZE = 600 cap which user pushed back on).
Stencil clipping confines content to the canvas rect using layer_stencil_mask / layer_stencil_test / layer_stencil_off.
Drop processing: gated on cursor inside the canvas rect (later moved to workspace-level routing).

Bug: os.execute cwd discovery:

content_store_init() initially tried mkdir "app\\data\\blobs" from Lua expecting cwd = Anchor2/. Debug prints revealed the engine does _chdir(game_folder) at startup — so when launched as ./app/anchor.exe app, cwd becomes Anchor2/app/. Fixed by using paths relative to app/ (e.g., data/blobs not app/data/blobs).
Also discovered that the workspace persisted state file .workspace_state.lua lives at Anchor2/app/.workspace_state.lua (not Anchor2/.workspace_state.lua as initially assumed).

Bug: Lua C-API stack index in l_engine_get_drops:

Heisenbug crashing on first drop. User reported "Segmentation fault" with no Lua error and no canvas trace prints.
After adding aggressive io.write + io.flush traces narrowing it down, found the actual crash was layer_draw_texture failing — but discovered an earlier latent bug in the engine.
Root cause: l_engine_get_drops had lua_rawseti(L, -3, i+1) but the stack only had [outer, inner] at that point — -3 is below the function's stack base. With release Lua's API checks compiled out, it was reading garbage memory as a Table*. Worked "by luck" in sub-step 1.5 but crashed in sub-step 2. Fixed by changing -3 → -2.
User: "no Lua error even" — pointed straight to C-side UB.

Bug: layer_draw_texture no framework wrapper:

After fixing the stack bug above, image drops still crashed. Trace prints showed crash at layer_draw_texture(ui_layer, el.image.handle, 0, 0).
Root cause: layer_draw_texture is the raw engine binding expecting a Layer* lightuserdata as arg 1. ui_layer is the Lua table {name, handle, filter, ...} returned by layer_new. lua_touserdata returns NULL for non-userdata → engine deref of NULL Layer pointer → segfault.
The framework wraps layer_rectangle, layer_push, layer_pop, layer_image, layer_texture etc. but NOT layer_draw_texture — the global layer_draw_texture is unshadowed. The anchor/layer.lua file's own header explicitly warns about this name-collision footgun.
Fix: use layer_image(ui_layer, el.image, 0, 0) (framework wrapper that extracts .handle and img.handle) instead of layer_draw_texture.

Sub-step 2 size policy change:

User noticed initial 717×477 image was being rendered at 599×399 (MAX_INITIAL_SIZE = 600 cap on largest dimension).
First fix: change cap to slot-aware (s = math.min(1, rect.w/w, rect.h/h)).
User pushed back: "Save native size... 2 also solves 1, we don't need to actually resize the image, the user can do that automatically. Once the image spawns, it's full size, if it goes beyond the slot, the user can diminish it themselves."
Final fix: no auto-shrink. Image spawns at native size. Stencil clip hides overflow. User resizes via handles (later) or keybinds (future).

Sub-step 3a: selection:

Click on element body → select topmost (last in elements list, drawn last) under cursor. Click empty → deselect. Ctrl+click skipped (workspace pane-swap).
Selection visual: 1px lavender ring around element bounds. Drawn inside stencil block so it clips with the image.
Hit-test in reverse order so the visually-topmost element wins.

Sub-step 3b: drag-to-move:

Single click handler covers both select + drag-start: clicking an element selects it AND captures cursor offset for the move drag. Mouse release ends the drag.
Drag mutates el.x / el.y in place each frame while state == 'moving'. Free positioning — element keeps real coords even when dragged off-canvas; stencil clip handles visuals.
Plain LMB drag = move element; Ctrl+LMB drag = workspace pane swap. The Ctrl gate disambiguates.

Sub-step 3 (continued): resize handles with corner + edge squares:

User requested: corner squares to scale + aspect-preserving, edge bands to resize-in-one-axis-with-aspect-preserved, visible markers, system cursor changes on hover.
Eight handles: 4 corner squares (always drawn) + 4 edge midpoint squares (only drawn when el.w >= s*3 / el.h >= s*3 so they don't overlap corners).
Made squares render INSIDE the image (anchored to the corresponding edge/corner growing inward) so they're never clipped at canvas boundaries — user explicitly asked for this.
HANDLE_SIZE = 8, EDGE_HIT = 6, MIN_SIZE = 24 (sized so 4 corners + edge midpoint can fit without overlapping diagonally).
Resize math: corners use scale = max(dw/orig_w, dh/orig_h, min_scale) — cursor leads on whichever axis dragged faster, opposite corner anchored. Edges use single-dim scale, opposite edge + orthogonal center anchored.
Captured pre-drag geometry at drag start (self.drag.pre = {x,y,w,h}) for undo command on release.
Cursor changes via CURSOR_FOR_HANDLE map: corner_tl/br → sizenwse, corner_tr/bl → sizenesw, edge_top/bot → sizens, edge_left/right → sizewe. Set every frame; engine's SDL_SetCursor no-ops when unchanged.

Sub-step 3c: persistence:

Canvas saves to app/data/canvases/scratch.lua as Lua return-table after every mutation (drop, drag-end, resize-end). Save triggers from undo commands' apply/revert.
Saved per element: {type='image', blob_id, x, y, w, h} — not the live image userdata (can't serialize).
Load on pane init: read_canvas_elements(path) parses + validates + re-resolves each blob_id via content_store_resolve. Elements with missing blobs are skipped with a stderr warning rather than aborting the whole load.
Hand-readable file with version = 1 file-format-version (separate from the runtime model version counter that came later).
Atomic writes deemed overkill for personal-use local-disk app.

Delete key:

Pressing Delete on a selected element removes it via a delete command. Bound to dedicated Delete key only (not Backspace — reserved for text-element editing in Part 3). Selection clears.

Undo / redo (sub-step 3 supplement):

New undo.lua module: global undo_stack + redo_stack, MAX_UNDO = 256, LIFO. New action clears redo stack.
Commands are tables with apply and revert methods. "Apply on push" pattern for add/delete (gesture creates cmd, calls apply, pushes). "Already applied" pattern for move/resize (gesture mutates in place during drag, cmd captures pre + post state at drag-end, pushes without calling apply).
Four canvas command types: make_add_command (insert/remove), make_delete_command (remove/re-insert at saved index), make_move_command (set x,y), make_resize_command (set x,y,w,h).
Commands target by pane_id (stable string) and elements by table identity (remove_by_identity helper). Robust against reordering.
Bound Ctrl+Z → undo, Ctrl+R → redo (user changed from Ctrl+Shift+Z / Ctrl+Y).
Handler lives at workspace level (handle_undo_keys) since undo stack is global, not pane-scoped.

Workspace bug: ensure_per_mode_state didn't merge defaults:

Discovered when split mode showed empty main slot for bare mode after a previous session's saved state had main_placeholder (which no longer existed). The validation in workspace_load_state stripped the invalid pane id, leaving the slot empty. ensure_per_mode_state then early-returned because per_mode[name] existed (just with the missing slot).
Fix: ensure_per_mode_state now merges defaults INTO existing state for any missing slots, rather than skipping. New panes added in code appear next session even with saved state; user's drag-swaps stay intact (their slots remain in saved state).

Sub-step 7a: model layer (model.lua):

New global models = {} registry keyed by stable string id. Each model: {id, kind, version, content}.
API: model_new(id, kind, content) (errors on duplicate id), model_get(id), model_bump(m) (increments version), model_destroy(id).
Procedural style, no event subscription. Views poll model.version per-frame and re-derive when it changes.
Canvas refactor: data moved from self.elements directly on the pane to self.model.content.elements. self.elements kept as a convenient alias (the table reference is stable since we only mutate in place).
canvas_model_load(id) returns existing model (idempotent) or creates from disk file.
canvas_model_id → disk path mapping: 'canvas:scratch' ↔ data/canvases/scratch.lua via canvas_path_for(id) helper. Generalizes to multi-canvas later (different IDs → different files).
Every mutation point bumps the model (commands, in-place drag updates). For drag mutations, bump happens every frame so other views see live updates.

Sub-step 7b: multi-view + split mode:

Two canvas panes (main_canvas and canvas_b) registered in main.lua, both using model_id='canvas:scratch'. Both canvas_model_load() calls return the same model instance.
New split template + mode + F4 keybind. Initially had asymmetric side_a (600) + main (fill) which made the test confusing because the two panes had different sizes. User pushed back.
Selection refactored from index-based (self.selected_idx) to element-reference-based (self.selected_el). Indices shift when another pane deletes earlier elements; refs don't.
Version polling added: at top of update, if self.last_seen_version ~= self.model.version then re-validate selection (clear if selected_el no longer in elements), abort drag if its target disappeared.
Defensive mouse_is_down(1) check in drag handler: if drag state is non-idle but mouse isn't held, missed a release event (e.g., mode switched mid-drag) — bail rather than snap element to cursor.
Workspace-level drop routing: new route_drops(rects) drains engine_get_drops() once at the workspace, looks up the pane under the cursor via slot_at, dispatches via new pane:on_drop(drop, rect) method. Without this, both canvas panes would call engine_get_drops() and whichever ran first would drain the queue for everyone.
pane:on_drop added to pane.lua for the new dispatch.

Stencil clear timing bug (between 7a and 7b):

User: "I can just drag it anywhere, I don't understand what I am supposed to test if I can just drag the image normally."
Initial diagnosis: stencil_mask in engine doesn't clear stencil before defining new mask region; sequential mask calls union instead of redefining. Pane B's element draws (rendered AFTER pane A's chrome) bleed into pane A's rect because the union stencil allowed both rects.
Fix: glClearStencil(0); glClear(GL_STENCIL_BUFFER_BIT); in COMMAND_STENCIL_MASK. Each mask now defines a fresh region.

Visual distinguishability between split-mode canvases:

Even after stencil fix, two panes with the same bg looked identical so user couldn't tell they were two panes. Added optional bg parameter to canvas pane (default theme.bg_base). Set canvas_b's bg to theme.bg_inset (darker variant from Catppuccin Macchiato palette) in main.lua. Subtle boundary now visible.

Coordinate model rethink — window-absolute vs canvas-local:

User: "shouldn't we want both panes to be exactly the same in terms of view? So if we have pane A with only the left portion of an image being drawn, and we have a copy of pane A displaying elsewhere, shouldn't we see that same left portion of the image instead of its right portion? The idea behind this is that I can post a game inside a blog post."
Recognized this as the right architectural critique. Current el.x, el.y were window-absolute → each pane just clipped its rect; same data produced different views in different panes.
Refactor: element coordinates are now canvas-local (relative to the pane's rect origin). Pane renders elements at (rect.x + el.x, rect.y + el.y) via a single outer layer_push(rect.x, rect.y, 0, 1, 1) translation that wraps the element/chrome rendering block. Input translates the other way: cx, cy = mx - rect.x, my - rect.y. All hit-testing, drop position, drag offset, resize anchor math uses canvas-local cx, cy + canvas-local el.x, el.y (same coordinate system).
Net result: two panes of the same size viewing the same canvas show identical content — the property required for embeds.
Existing saved canvas data was window-absolute, would shift visually under new semantics — user instructed to rm data/canvases/scratch.lua.
Updated split mode: equal-sized canvas_left (600) + canvas_right (600) edge slots with a middle fill slot hosting panel_a as filler. User explicitly suggested "separated by something irrelevant in the middle" to make the test obvious.

Stencil bleed (SDF padding bug) workaround:

After canvas-local refactor, user reported image bleeding 2-3 pixels past canvas_left's right edge into panel_a.
Investigation: the engine's SDF rect fragment shader doesn't discard fragments fully outside the rect — alpha just fades to 0. The quad geometry has 2 pixels of padding around the requested rect for AA. With colormask off (stencil mask mode), every fragment in the padded quad still reaches the stencil op and writes 1. Stencil ends up marked across the full padded quad → image draws past the actual rect boundary still pass the stencil test.
Quick workaround in canvas.lua: inset the stencil mask shape by 2 pixels (SDF_PAD = 2) so the padded quad lands exactly at the canvas rect boundary. Commented as a hack with proper fix being a shader-side discard.

Step 8 explanation:

User asked the difference between "two panes view same model" (what we have) and step 8 (embedded views).
Clarified: current setup has panes living in workspace SLOTS — template-defined positions, app-level layout. Step 8 adds a second host: panes can also live as CANVAS ELEMENTS — free-positioned in another canvas's content, persisted with that canvas, like an image.
Concrete use case: "embed game in blog post" requires the game-canvas to be an element of the blog-post-canvas, not just a parallel slot.
Step 8 generalizes the pane-host abstraction. The same pane class works in both hosts; what differs is who calls pane:update(rect) with what rect, and how input routes (recursive routing into the embedded view's rect).

Decision to pause:

After step 7b validation and step 8 explanation, user chose to pause and resume in next session: "Let's pause here". Session was long, step 8 deserves its own focused start, lots of architectural ground covered to settle on.

Documentation updates:

Updated app/plan.md ## Current Status section: replaced 2026-04-17 status with detailed Phase 1 Part 2 shipped/pending checklist, listed every engine + Lua addition, documented model layer + canvas-local coords + workspace drop routing as locked architectural decisions.
Updated app/docs/ui_architecture.md TL;DR to reflect that model–view separation and multi-view are shipped (step 7), canvas-local coords are shipped (7b), and embedded-element host is the next step (8). Added notes about workspace owning drop routing, selection-by-reference, and global undo.

Files added/modified this session:

Engine: Anchor2/engine/src/anchor.c (drop events, cursor API, focus-clickthrough hint, stencil clear, ~150 lines added)
Engine binary: rebuilt and copied to Anchor2/app/anchor.exe and Anchor2/arena/anchor.exe
New: Anchor2/app/content_store.lua, Anchor2/app/undo.lua, Anchor2/app/model.lua, Anchor2/app/panes/canvas.lua
Modified: Anchor2/app/main.lua, Anchor2/app/workspace.lua, Anchor2/app/pane.lua
Modified: Anchor2/app/plan.md, Anchor2/app/docs/ui_architecture.md

Let's continue on the Anchor App. Last session was named Anchor App Phase 1 Part 1, you can read about it in logs/, and also read relevant files in the Anchor2/app folder itself. Get oriented first and tell me what we decided to do next.

Bash (ls E:/a327ex/logs/ | grep -i "anchor.app")

ls: cannot access 'E:/a327ex/logs/': No such file or directory

Glob (/logs//AnchorApp*)

No files found

Glob (/Anchor2/app//*.md)

Anchor2\app\docs\visual_identity.md
Anchor2\app\design.md
Anchor2\app\plan.md
Anchor2\app\docs\ui_architecture.md

Glob (/logs//*.md)

a327ex-site\media\logs\2026-01-01-07-37\ANCHOR.md
a327ex-site\media\logs\2026-01-01-07-37\CLAUDE.md
a327ex-site\media\logs\2026-01-02-10-00\ANCHOR.md
a327ex-site\media\logs\2026-01-02-10-00\CLAUDE.md
a327ex-site\media\logs\2026-01-01-07-37\IMPLEMENTATION_PLAN.md
a327ex-site\media\logs\2026-01-02-10-00\IMPLEMENTATION_PLAN.md
anchor.blot.im\logs\2026-01-02_18-59.md
anchor.blot.im\logs\2026-01-03_12-30.md
anchor.blot.im\logs\2026-01-03_15-30.md
anchor.blot.im\logs\anchor-phase-1.md
anchor.blot.im\logs\anchor-phase-10-part-1.md
anchor.blot.im\logs\anchor-phase-10-part-10.md
anchor.blot.im\logs\anchor-phase-10-part-2.md
anchor.blot.im\logs\anchor-phase-10-part-3.md
anchor.blot.im\logs\anchor-phase-10-part-4.md
anchor.blot.im\logs\anchor-phase-10-part-5.md
anchor.blot.im\logs\anchor-phase-10-part-6.md
anchor.blot.im\logs\anchor-phase-10-part-7.md
anchor.blot.im\logs\anchor-phase-10-part-8.md
anchor.blot.im\logs\anchor-phase-10-part-9.md
anchor.blot.im\logs\anchor-phase-2.md
anchor.blot.im\logs\anchor-phase-3-part-1.md
anchor.blot.im\logs\anchor-phase-3-part-2.md
anchor.blot.im\logs\anchor-phase-3-part-3.md
anchor.blot.im\logs\anchor-phase-3-part-4.md
anchor.blot.im\logs\anchor-phase-4.md
anchor.blot.im\logs\anchor-phase-5.md
anchor.blot.im\logs\anchor-phase-6.md
anchor.blot.im\logs\anchor-phase-7.md
anchor.blot.im\logs\anchor-phase-8.md
... [71 more lines]

Bash (ls E:/a327ex/)

Anchor/
Anchor-YueScript/
Anchor-lua/
Anchor2/
BYTEPATH/
Danpenzero/
Null/
Orblike/
Psyonia/
RETICLE/
RTFX/
Ricochet/
SNKRX/
a327ex-site/
a327ex.com-blog/
anchor.blot.im/
cute_action.mp3
cute_action.wav
emoji-aimer/
emoji-ball-battles/
emoji-ball-battles-generated/
emoji-ball-bounce/
it-follows/
lane-battle/
ld54-remake/
meal_prep.md
music-theory/
neural-networms/
notes/
petri/
... [7 more lines]

Glob (anchor.blot.im/logs/nchorpp*)

anchor.blot.im\logs\anchor-app-design.md
anchor.blot.im\logs\anchor-app-ui-discussion.md
anchor.blot.im\logs\anchor-app-phase-1-part-1.md

Glob (a327ex-site//nchorpp*)

a327ex-site\media\notes\ui-design-workflow\Claude AnchorApp 1.html
a327ex-site\media\notes\ui-design-workflow\Claude AnchorApp 2.html
a327ex-site\media\notes\ui-design-workflow\Claude AnchorApp 3.html
a327ex-site\media\notes\ui-design-workflow\Claude AnchorApp 4.html
a327ex-site\media\notes\ui-design-workflow\Claude AnchorApp 6.html
a327ex-site\media\notes\ui-design-workflow\Claude AnchorApp 5.html
a327ex-site\logs\anchor-app-design.md
a327ex-site\logs\anchor-app-phase-1-part-1.md
a327ex-site\logs\anchor-app-ui-discussion.md

Read (E:\a327ex\anchor.blot.im\logs\anchor-app-phase-1-part-1.md)

File content (96159 tokens) exceeds maximum allowed tokens (25000). Use offset and limit parameters to read specific portions of the file, or search for specific content instead of reading the whole file.

Bash (wc -l E:/a327ex/anchor.blot.im/logs/anchor-app-phase-1-part-1.md)

4160 E:/a327ex/anchor.blot.im/logs/anchor-app-phase-1-part-1.md

Read (E:\a327ex\anchor.blot.im\logs\anchor-app-phase-1-part-1.md)

3900 2545    **1. Focus doesn't transfer on Ctrl+click** — the panel pane's focus-on-click is gated on `not ctrl_held()` precisely *because* I didn't want Ctrl-drag to also fire focus. But that's wrong: focus should follow the click regardless of modifiers, and B losing focus when A is grabbed is correct. Better fix: hoist focus-on-click out of panel.lua entirely and let the **workspace** drive it uniformly. Click on slot S → `pane_focus_id = workspace_state.slot_panes[S]`. That way every pane behaves the same and we never write per-pane focus code again.
3901    2546    
3902    2547    **2. Drag affordance** — when Ctrl is held, the hovered slot gets a faint outline so users can discover what's draggable. Distinct from (and fainter than) the active drag highlight (2px lavender ring).
3903    2548    
3904    2549    **3. Visual hierarchy** — three states with three intensities:
3905    2550    | State | Visual |
3906    2551    |---|---|
3907    2552    | Ctrl held + hover (idle) | faint 1px outline on hovered slot |
3908    2553    | Active drag, hovered slot ≠ source | 2px lavender ring on drop target + ghost |
3909    2554    | Focused pane | 1px lavender border (panel rendering) |
3910    2555    
3911    2556    Need to pick a color for the faint affordance. Let me check what alpha support the color/layer system has.
3912    2557    
3913    2558    &lt;details&gt;
3914    2559    &lt;summary&gt;&lt;code&gt;Bash (grep -n -E "function color\(|color = function|^color\s*=" E:/a327ex/Anchor2/fram...)&lt;/code&gt;&lt;/summary&gt;</code></pre>
3915    
3916    </details>
3917    
3918    Let me check the source JSONL to see if those messages are actually present, then investigate the conversion script.
3919    
3920    <details>
3921    <summary><code>Bash (python -c "
3922    import json
3923    path = r'C:\Users\adn\.claude\projects\E--a327ex\f2caad4...)</code></summary>
3924    
3925    <pre><code>(56, 'assistant', 2755, 'Got it. Here\'s where we left off:  ## Recap of "Anchor App UI Discussion"  The session was an architecture-heavy discuss')
3926    (436, 'assistant', 2770, 'All eight files parse. Step 4 done.  ## What you should see when you run  Visually identical to before: - **Topbar** � m')
3927    (440, 'user', 11, 'Looks good.')
3928    (442, 'assistant', 73, 'Step 5: drag-to-swap. Let me first check the input API for modifier keys.')
3929    (449, 'assistant', 1180, "Engine uses `'lctrl'`/`'rctrl'` for Ctrl. The user is on Windows so Ctrl is the natural drag modifier (would be Cmd on M")
... [230 more lines]

Read (E:\a327ex\Anchor2\app\plan.md)

1    # Anchor — The Omega App
2   
3   ## Vision
4   
5   The omega app is the next evolution of Anchor: a single application for all creative work, built entirely with the Anchor engine. It replaces the scattered collection of tools (Notepad, NeoVim, Claude Code, Explorer, DAW, browser) with one unified environment owned completely by the user.
6   
7   The core insight comes from 4 months of using Claude Code daily: AI is good enough that you stop reading code. Once you stop reading code, you lose ownership of the codebase. Once you lose ownership, you realize what you actually needed to own wasn't the code — it was the *environment*. The code is replaceable. The environment shapes everything.
8   
9   ### The Ownership Thesis
10  
11  Claude Code's terminal UX nudges you away from ownership. You see only the snippets the AI chose to focus on. There's no physicality, no sense of place in the codebase. The file is never yours. Tools like Cursor have an inherent advantage because the feeling of physicality and place turns out to be important.
12  
13  The solution: build your own space. Not just an editor — a complete workspace where every feature exists because it's needed, where AI integration works exactly right, where ownership is absolute because you built everything yourself.
14  
15  ### The Felt Sense of Place
16  
17  One framing that emerged was the app as a personal MMO — a 2D world where the "city" is the workspace. Different districts for different work, NPCs as AI agents, files as inventory items, quests as commitments. This isn't the practical implementation, but it surfaced something real: **the felt sense of place matters**. The reason code ownership was lost isn't just that code stopped being read — it's that there was never a *place* in it. The code existed nowhere. It was a stream of diffs.
18  
19  The practical version keeps the ideas with genuine functional benefit — spatial canvases, persistent AI agents, modes, filesystem-as-database — and drops the fantasy elements. Closer to a meticulously customized Emacs or a Bloomberg Terminal than to Stardew Valley. Dense, keyboard-first, information-rich, every pixel earning its place. But retaining warmth through considered visual design and the fact that it's a place built for oneself.
20  
21  ### Triple Use
22  
23  Everything built for this app has potentially triple use:
24  1. The development environment (daily work tool)
25  2. The website (a327ex.com rendered by the engine via WASM)
26  3. Artistic artifacts (games, interactive books, music)
27  
28  The engine already compiles to WebAssembly. The website becomes an Anchor app. Blog posts are rendered by the engine, not HTML. Interactive elements are trivial because they're already game objects. The text layout system built for the app becomes the text layout system for the website. Everything compounds. Nothing is throwaway.
29  
30  This also serves the seven stories project — books merged with games where interactive elements live inline with narrative. Displaying a website and displaying a game are the same thing: putting pixels on the screen in the exact way you want.
... [508 more lines]

Bash (ls E:/a327ex/Anchor2/app/ && echo "---" && ls E:/a327ex/Anchor2/app/docs/)

anchor/
anchor.exe*
assets/
design.md
docs/
main.lua
pane.lua
panes/
plan.md
rect.lua
run.bat
widgets.lua
workspace.lua
---
ChatGPT design 1.png
ChatGPT design 10.png
ChatGPT design 2.png
ChatGPT design 3.png
ChatGPT design 4.png
ChatGPT design 5.png
ChatGPT design 6.png
ChatGPT design 7.png
ChatGPT design 8.png
ChatGPT design 9.png
mockup.html
mockup_agent_ux_study.html
mockup_book_and_game.html
mockup_code_editor.html
mockup_music_piano_roll.html
mockup_v2_browse.html
... [8 more lines]

Read (E:\a327ex\Anchor2\app\main.lua)

1    --[[
2     Anchor app — Phase 1, end of step 4 (workspace + template loader).
3   
4     This file is the entry point: it sets up the engine, theme, fonts, the UI
5     layer, then delegates per-frame rendering to the workspace shell. The
6     workspace walks a template (slots), looks up which pane is in each slot
7     (mode binding), and calls each pane's :update(dt, input, rect).
8   
9     Update vs draw: all UI work — hit-testing, state machine, layer command
10    queueing — runs from `update(dt)`. `draw()` is two lines that flush the UI
11    layer to the screen. See `docs/ui_architecture.md` § 4 "Why one method, not
12    two" for the reasoning.
13  
14    Resolution model: see plan.md "Resolution Model". UI code is written in raw
15    logical pixels. dpr=1 today on a single 1920×1080 monitor; the engine handles
16    device-pixel sizing internally when dpr changes (HiDPI / WASM publishing).
17    Nothing in this file should assume dpr=1.
18  
19    Filter mode: every UI layer + font is smooth (SDF edges, grayscale atlas,
20    linear sampling). Rough mode is reserved for embedded pixel-art game views.
21  
22    Authoritative visual reference: docs/mockup_v2_ui_kit.html.
23  ]]
24  
25  require('anchor')({
26    width = 1920,
27    height = 1080,
28    title = 'Anchor',
29    scale = 1,
30    vsync = true,
... [181 more lines]

Read (E:\a327ex\Anchor2\app\design.md)

1    # Anchor App — Design Specification
2   
3   *The implementation-level companion to `docs/visual_identity.md`.*
4   *Version — v2.0, revision 2026-04-23.*
5   
6   ---
7   
8   ## Table of contents
9   
10  0. [Foreword](#0-foreword)
11  1. [Philosophy](#1-philosophy)
12  2. [Foundations](#2-foundations)
13     - 2.1 Target hardware & viewport
14     - 2.2 Grid & rhythm
15     - 2.3 Rendering assumptions (Anchor 2)
16     - 2.4 Filter modes
17  3. [Design tokens](#3-design-tokens)
18     - 3.1 Color
19     - 3.2 Typography
20     - 3.3 Spacing
21     - 3.4 Stroke, radius, elevation
22     - 3.5 Motion
23  4. [Surface primitives](#4-surface-primitives)
24     - 4.1 Top status bar
25     - 4.2 Bottom status bar
26     - 4.3 Side panels
27     - 4.4 Section headers
28     - 4.5 Dividers
29     - 4.6 Panel header row
30  5. [Interactive state model](#5-interactive-state-model)
... [90 more lines]

Read (E:\a327ex\Anchor2\app\docs\ui_architecture.md)

1    # Anchor App UI Discussion
2   
3   Captured 2026-04-28. Authoritative reference for the app's UI architecture.
4   If you are a future session picking this up, read this file *after* `plan.md`
5   and *before* writing any UI code — most of the decisions here are non-obvious
6   from the codebase alone and were settled by long discussion.
7   
8   The visual side of the UI is covered separately: see `docs/visual_identity.md`
9   and `docs/mockup_v2_ui_kit.html` (the authoritative visual reference). This
10  file is the *system architecture*: how the UI is structured in code, what the
11  units of composition are, how state flows between them.
12  
13  ---
14  
15  ## TL;DR
16  
17  - **Hybrid mode UI**: retained workspace shell (panes are long-lived stateful objects you can drag between slots) + immediate-mode widget functions inside panes (buttons, chips, rows — drawn each frame from state).
18  - **Two-tier layout**: a workspace template defines named **slots** (edge slots + one fill slot); each mode assigns specific **panes** to those slots. Slot names are positional and generic (`side_a`, `main`, `status_top`); pane names are stable identities (`code_editor`, `agent_oracle`).
19  - **RectCut** is the layout primitive inside panes. Small module (~50 lines), mutating-parent style, supplemented by helpers (contract, center, split_h/v).
20  - **Model–view separation**: a separate model layer holds files, documents, agent conversations. Panes are *views* of models. Multiple panes can view the same model; edits propagate via per-frame version polling.
21  - **Two host types** for panes: workspace slot host (full chrome) or canvas-element host (panes embedded as content inside documents). Same pane class either way.
22  - **Resolution model**: UI code in raw logical pixels; engine handles device-pixel sizing of smooth FBOs and font atlases via a `dpr` factor (1.0 today). See `plan.md` § Resolution Model.
23  - **Authoritative visual reference**: `docs/mockup_v2_ui_kit.html`. Older v1 mockups superseded.
24  
25  ---
26  
27  ## 1. Why this shape
28  
29  The UI sits in the awkward middle of the action-based vs rules-based gameplay
30  spectrum (per the author's essay on the topic). Different *scopes* of the UI
... [70 more lines]

78:- Used Ctrl as modifier on Windows (engine exposes `'lctrl'`/`'rctrl'`; no GUI/Cmd key on Windows; cross-platform mod-key resolution noted as TODO).
100:- Known footguns flagged: drag while mode-switch keypress could orphan source slot (cancel drag on mode switch is a TODO); rename a pane id in code → falls back to default for that slot; stale modes self-heal on next save.
102:**Discussion of next steps (no implementation):**
103:- User asked what's next; explained step 7 (model layer ~300 lines) is plumbing for the view/model split, alone has weak visible payoff. Three options presented honestly:
323:113 - `Anchor2/app/plan.md` — added Resolution Model section, updated "Locked since original draft" with v2 UI kit authoritative source + resolution-model lock + revised "what's next" pointing to UI kit primitives instead of canvas; added `ui_architecture.md` to the future-session reading order.
425:52:**What's next:**
453:52  **What's next:**
770:If anything looks wrong (gap pixels, off-by-ones, columns not summing to the body width), that's a Rect bug to chase. If it looks right, the next step is rip the test block out and refactor `draw_topbar()` / `draw_botbar()` to use Rect — but I'll wait for your test before doing that.
776:> Seems like it's good, what's next?
1304:Memory saved so this doesn't get rediscovered next session. Run the app again — left-click should fire on the buttons now and the `clicks:` counter in the header readout should increment.
1894:## What's next
2080:## What's next
2297:After 3 lands, **step 4** (workspace + template loader) is the natural next step. That's where the topbar/botbar stop being `paint_*` functions and become two `edge` slot panes registered in a template — a real test of the whole system. Want to push on?
2327:> What's next?
2599:Engine uses `'lctrl'`/`'rctrl'` for Ctrl. The user is on Windows so Ctrl is the natural drag modifier (would be Cmd on Mac via `'lgui'`/`'rgui'` once we ever cross-platform — adding a TODO).
2990:> Yep, everything is working correctly. What's next?
3183:> Everything seems to work. What's next? Don't do it, just tell me.
3185:The documented next step is **Step 7: Model layer** — but I'd flag that doing it alone has weak visible payoff, and there are alternatives worth considering before committing.
3526:- Used Ctrl as modifier on Windows (engine exposes `'lctrl'`/`'rctrl'`; no GUI/Cmd key on Windows; cross-platform mod-key resolution noted as TODO).
3548:- Known footguns flagged: drag while mode-switch keypress could orphan source slot (cancel drag on mode switch is a TODO); rename a pane id in code → falls back to default for that slot; stale modes self-heal on next save.
3550:**Discussion of next steps (no implementation):**
3551:- User asked what's next; explained step 7 (model layer ~300 lines) is plumbing for the view/model split, alone has weak visible payoff. Three options presented honestly:

Read (E:\a327ex\anchor.blot.im\logs\anchor-app-phase-1-part-1.md)

3170 
3171    ## Phase 1 closeout
3172    | | | |
3173    |---|---|---|
3174    | ✅ 1 | Rect | 98 |
3175    | ✅ 2 | Widgets + bar refactor | ~289 + 210 |
3176    | ✅ 3 | Pane abstraction | 109 |
3177    | ✅ 4 | Workspace + first real panes | 365 in workspace + ~150 in panes |
3178    | ✅ 5 | Drag-to-swap | (folded into 365 above) |
3179    | ✅ 6 | Mode switching + persistence | (folded above) + 210 main |
3180    
3181    Total ~1170 lines for the workspace-shell tier. After step 6 confirms, **steps 7–10 are deferred-or-later** per the architecture doc (model layer, embedded views, view clipboard, publishing). Step 7 (model layer with version counters for the view/model split) is the next architectural slice — that's where panes start being views of underlying models that can be edited from multiple panes simultaneously. Want to push on, or pause here for the foundation to settle?
3182    
3183    > Everything seems to work. What's next? Don't do it, just tell me.
3184    
3185    The documented next step is **Step 7: Model layer** — but I'd flag that doing it alone has weak visible payoff, and there are alternatives worth considering before committing.
3186    
3187    ## Step 7 as written (~300 lines)
3188    
3189    Per [docs/ui_architecture.md § 5](Anchor2/app/docs/ui_architecture.md): a separate data layer of **models** (file contents, document contents, agent conversations, directory listings, tag database). Each model has:
3190    - A stable ID (`file:<path>`, `document:<id>`, `conversation:<agent>:<id>`).
3191    - A version counter, bumped on every mutation.
3192    - Optional disk persistence.
3193    
3194    Panes hold a `model_id` (already do — the field exists in the pane class), poll the model's version each frame, and re-derive their display when it bumps. This is what lets two panes view the same file and stay in sync, and what makes the eventual "clone this view into a document" / "publish a snapshot" flows possible.
3195    
3196    **Honest concern:** step 7 alone is plumbing. The visible test would be artificial — say, two `model_echo` panes pointing at the same model, plus a button widget that bumps the version, both panes update. Cute, but it doesn't make the app feel more capable. Step 7's value lights up when steps 8 (embedded-view canvas elements) and 9 (view clipboard) ride on top.
3197    
3198    ## Three honest options
3199    
... [200 more lines]

Oriented. Here's where things stand.

What Phase 1 Part 1 actually shipped (steps 1–6, ~1170 lines in Anchor2/app/):

rect.lua — RectCut layout primitive
widgets.lua — immediate-mode widgets + topbar/botbar refactored onto them
pane.lua — pane abstraction (long-lived stateful UI objects with IDs/types)
workspace.lua + first real panes — template/slot system, mode binding, the topbar/botbar became real edge-slot panes
Drag-to-swap (Ctrl+drag a pane between slots, lavender ring affordance, focus-on-click hoisted to workspace)
Mode switching (F1=kit, F2=compose, F3=bare) + state persistence on exit

You can see the result in main.lua — kit mode has 5 panes (status_top/status_bot/side_a/side_b/main), and switching modes rebinds which panes occupy which slots.

What we did NOT decide — at the end of the session I laid out three options for what to do next, and you ended the session ("Let's end the session here then") without picking. So the decision is still open. The three options were:

A. Stay on the architectural path — steps 7+8+9 as a unit (~700+ lines honestly). Model layer (every file/doc/conversation is a model with version counter) → embedded-view canvas elements (panes inside documents) → view clipboard (Cmd+Shift+C captures live view state, paste anywhere). End state: edit a code pane, switch modes, paste it inline as a blog-post element, edits propagate. Validates the whole model–view bet docs/ui_architecture.md is built around. But weak visible payoff until all three land.

B. Skip ahead to one concrete pane type — file browser. Lists files in a directory, keyboard nav, click to "open" (printf for now). Slots into side_a. Forces real questions about keyboard focus and "what does a pane do". Smallest thing that makes the app feel like a workspace instead of a layout demo.

C. Polish the foundation (~80 lines). Extract ui_panel_chrome (bg+border+focus ring, currently duplicated), cancel active drag on mode-switch, per-pane min-size hints. Boring but every future pane gets cleaner.

My read at the time leaned B unless you specifically wanted to validate the model–view split soon. That read still holds for me — a file browser surfaces concrete decisions (focus, keyboard nav, what "open" means) that A defers and C doesn't address.

Which one do you want to push on?

Let's do B, create one pane time that is the free-flowing canvas one. The main functionality we should add to it is the ability to drag images into it from external sources. This image should be saved somewhere and then displayed, and then once we do steps 7+8+9 we can also test if pane copying works and how we'll handle references of content (the images) and so on. Seems good?

Yes, that's a great pick — better than the file browser, actually. A canvas pane with image drop forces real answers to questions we'd otherwise defer:

Where does content live on disk? (foreshadows Phase 3 filesystem)
How is content referenced from a document? (path vs content-hash vs stable ID — exactly the question step 7's model layer has to answer)
What's the document serialization format? (a canvas with one image element is the smallest non-trivial doc)
How does the engine receive OS-level drops? (engine plumbing we'll need everywhere)

And it produces the visible payoff B promised — drop a screenshot, see it on the canvas, move it around. Concrete and testable.

Before I start I want to check a couple of things and ask a few decisions. Let me first verify the engine already has SDL drop-file events exposed (without that we have a Track B detour before any of this works).

Grep (drop|DROPFILE|SDL_EVENT_DROP|drag.*drop)

1902:        // Fixed size queue - don't grow, just drop the command
1907:                fprintf(stderr, "Error: Command queue full (%d commands). Dropping draw calls.\n",

Grep (drop|drag)

No files found

Zero drop-file support in the engine. SDL emits SDL_EVENT_DROP_FILE events but they're not wired up. That's a small Track B detour — ~30–60 lines of C plus a Lua accessor — but it has to land before any of this works.

Let me also check what the framework has for image loading:

Grep (image|texture|^function image|function texture)

E:\a327ex\Anchor2\framework\anchor\layer.lua:235:function layer_shader_set_texture(lyr, shader, name, texture_id, unit)
E:\a327ex\Anchor2\framework\anchor\layer.lua:236:  eng.shader_set_texture(lyr_handle(lyr), shader, name, texture_id, unit or 1)
E:\a327ex\Anchor2\framework\anchor\image.lua:5:    images.player = image_load('player', 'assets/player.png')
E:\a327ex\Anchor2\framework\anchor\image.lua:13:function image:new(handle)
E:\a327ex\Anchor2\framework\anchor\image.lua:15:  self.width = texture_get_width(handle)
E:\a327ex\Anchor2\framework\anchor\image.lua:16:  self.height = texture_get_height(handle)
E:\a327ex\Anchor2\framework\anchor\image.lua:20:function image_load(name, path)
E:\a327ex\Anchor2\framework\anchor\image.lua:21:  local handle = texture_load(path)
E:\a327ex\Anchor2\framework\anchor\memory.lua:114:  {'gl_tex_bytes',   'gl_texture_bytes','bytes'},

Bash (ls E:/a327ex/Anchor2/framework/anchor/ && echo "---" && ls E:/a327ex/Anchor2/app...)

animation.lua
array.lua
camera.lua
class.lua
collider.lua
color.lua
font.lua
helpers.lua
image.lua
init.lua
input.lua
layer.lua
math.lua
memory.lua
object.lua
physics.lua
shake.lua
spring.lua
spritesheet.lua
timer.lua
---
animation.lua
array.lua
camera.lua
class.lua
collider.lua
color.lua
font.lua
helpers.lua
image.lua
... [10 more lines]

Image loading exists (image_load(name, path) → wraps texture_load). So the data path is fine — we just need OS-level drop-file events, then image_load handles the rest.

Before I start, a few decisions to make. Let me load the question tool.

ToolSearch

[
  {
    "type": "tool_reference",
    "tool_name": "AskUserQuestion"
  }
]

AskUserQuestion

User has answered your questions: "Where should dropped images be stored on disk?"="Content-hash seems good, but a327ex-site has my website on my VPS now. This means I have a server, and I want the entire engine to eventually work on my server, so I can use it anywhere (eventually). I'm saying this because we might have to make certain decisions now that will make it easier for us in the future to do that.", "Should canvas state (image positions) persist across app restarts?"="Yes — define minimal doc format now (Recommended)", "How much canvas interaction should the first slice include?"="Drop + display + drag-to-move (Recommended)". You can now continue with the user's answers in mind.

Good catch on the server. Content-hash storage is actually the most server-friendly choice — let me lay out what "design for server now" means concretely so we're not just hand-waving:

Design that survives going to server

Identifier shape: opaque blob IDs, never paths.

Documents reference content as blob:<sha256>.<ext> — never data/blobs/abc.png. The string blob:abc123....png is the universal handle. A tiny resolver translates it to a renderable resource:

Local (today): blob:abc.png → Anchor2/app/data/blobs/abc.png → image_load
Server (later): blob:abc.png → https://a327ex.com/blobs/abc.png → HTTP fetch (Track B's HTTP client) → cache locally → image_load
Hybrid (eventual): try local first, fall back to HTTP, cache the result

The document format never changes. The resolver is the only thing that grows a remote path.

Why content-hash specifically wins for server:

Hashes are globally unique. Same image dropped on desktop and on the server produce the same hash → same identity. Original-filename storage breaks this (everyone has a screenshot.png).
Sync becomes a set difference. "Server has these hashes, I have these hashes" → upload the diff. No reconciliation, no rename detection, no "is this the same file?" guessing.
HTTP caching is free. Hash-named files are immutable forever, so Cache-Control: immutable works perfectly. Browsers and CDNs love this.
Documents are portable. A canvas exported with blob:abc.png references can be rendered on any machine that can resolve those blobs — desktop, server, or browser via WASM.

Two-function content store API today:

content_store_put(source_path) → blob_id   -- hash, copy to blobs/, return id
content_store_resolve(blob_id) → image     -- local resolver today; HTTP fallback later

When the server day comes, resolve grows a remote path; nothing else changes.

Storage on disk: Anchor2/app/data/blobs/<hash>.<ext> flat for now. Sharding (<first2>/<rest>) is a one-line directory restructure when blob count justifies it.

Document format: Anchor2/app/data/canvases/scratch.lua returning a Lua table: lua return { version = 1, elements = { {type='image', blob_id='blob:abc123....png', x=120, y=80, w=640, h=480}, ... }, } Lua-native (matches workspace_save_state's style), easy to serialize/deserialize. When the server serves canvases over HTTP, we add a JSON transcode at the boundary — the in-memory representation stays the same.

Implementation plan (one slice at a time)

Three sub-steps; you test between each:

1. Engine drop-file events (~50 lines C in Anchor2/engine/src/anchor.c + Lua accessor). - Capture SDL_EVENT_DROP_FILE in the SDL event loop, queue paths. - Expose engine_get_dropped_files() returning a list (and clearing the queue), per-frame poll. - Build engine. Smoke test: drop a file on the window, prints "[drop] C:/path/to/file.png".

2. Content store + image element (~80 lines Lua). - content_store_put (sha256 via existing engine hash, or roll a tiny pure-Lua sha for now), content_store_resolve. - New panes/canvas.lua pane type — replaces main_placeholder in kit mode's main slot. - Drop file → content_store_put → image element appears at drop position, native size capped to slot rect. - No persistence yet — just drop and display.

3. Selection + drag-to-move + persistence (~70 lines Lua). - Click-on-image → select (1px lavender ring per the kit). Click empty → deselect. - Drag selected image to move. Constrain to slot bounds. - Save canvas to data/canvases/scratch.lua on app exit. Load on startup.

After 3 lands, dropping the same screenshot twice produces one file on disk and two elements; closing/reopening the app preserves everything; and steps 7+8+9 will be able to test "two canvas panes referencing the same blob, edits propagate" without rework.

Does this match what you had in mind? If yes I'll start with sub-step 1 (engine drop-file events).

Yup.

Starting sub-step 1: engine drop-file events. Let me find the SDL event loop in the engine.

Grep (SDL_EVENT|SDL_PollEvent|case SDL)

2701:        case SDL_SCANCODE_SPACE: return "space";
2702:        case SDL_SCANCODE_RETURN: return "enter";
2703:        case SDL_SCANCODE_ESCAPE: return "escape";
2704:        case SDL_SCANCODE_BACKSPACE: return "backspace";
2705:        case SDL_SCANCODE_TAB: return "tab";
2706:        case SDL_SCANCODE_LEFT: return "left";
2707:        case SDL_SCANCODE_RIGHT: return "right";
2708:        case SDL_SCANCODE_UP: return "up";
2709:        case SDL_SCANCODE_DOWN: return "down";
2710:        case SDL_SCANCODE_LSHIFT: return "lshift";
2711:        case SDL_SCANCODE_RSHIFT: return "rshift";
2712:        case SDL_SCANCODE_LCTRL: return "lctrl";
2713:        case SDL_SCANCODE_RCTRL: return "rctrl";
2714:        case SDL_SCANCODE_LALT: return "lalt";
2715:        case SDL_SCANCODE_RALT: return "ralt";
2716:        case SDL_SCANCODE_F1: return "f1";
2717:        case SDL_SCANCODE_F2: return "f2";
2718:        case SDL_SCANCODE_F3: return "f3";
2719:        case SDL_SCANCODE_F4: return "f4";
2720:        case SDL_SCANCODE_F5: return "f5";
2721:        case SDL_SCANCODE_F6: return "f6";
2722:        case SDL_SCANCODE_F7: return "f7";
2723:        case SDL_SCANCODE_F8: return "f8";
2724:        case SDL_SCANCODE_F9: return "f9";
2725:        case SDL_SCANCODE_F10: return "f10";
2726:        case SDL_SCANCODE_F11: return "f11";
2727:        case SDL_SCANCODE_F12: return "f12";
2728:        case SDL_SCANCODE_INSERT: return "insert";
2729:        case SDL_SCANCODE_DELETE: return "delete";
2730:        case SDL_SCANCODE_HOME: return "home";
... [27 more lines]

Grep (SDL_QUIT|SDL_KEYDOWN|SDL_MOUSEBUTTON|SDL_DROP|SDL_WINDOWEVENT)

10005:        if (event.type == SDL_QUIT) {
10009:        if (event.type == SDL_KEYDOWN && !event.key.repeat) {
10055:        if (event.type == SDL_MOUSEBUTTONDOWN) {
10069:        if (event.type == SDL_MOUSEBUTTONUP) {
10087:        if (event.type == SDL_WINDOWEVENT) {
10088:            if (event.window.event == SDL_WINDOWEVENT_FOCUS_GAINED) {
10560:                if (event.type == SDL_QUIT) {
10563:                if (event.type == SDL_KEYDOWN && !event.key.repeat) {

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

10000        #endif
10001   
10002       // Process events every frame (not tied to fixed timestep)
10003       SDL_Event event;
10004       while (SDL_PollEvent(&event)) {
10005           if (event.type == SDL_QUIT) {
10006               running = false;
10007           }
10008           // Track keyboard state
10009           if (event.type == SDL_KEYDOWN && !event.key.repeat) {
10010               last_input_type = INPUT_TYPE_KEYBOARD;
10011               #ifdef __EMSCRIPTEN__
10012               audio_try_unlock();
10013               #endif
10014               SDL_Scancode sc = event.key.keysym.scancode;
10015               if (sc < SDL_NUM_SCANCODES) {
10016                   keys_current[sc] = true;
10017               }
10018               // Capture mode: capture the key
10019               if (capture_mode && captured_control[0] == '\0') {
10020                   const char* key_name = scancode_to_key_name(sc);
10021                   if (key_name) {
10022                       snprintf(captured_control, sizeof(captured_control), "key:%s", key_name);
10023                   }
10024               }
10025               // Built-in key handling (skip if in capture mode)
10026               if (!capture_mode) {
10027                   if (event.key.keysym.sym == SDLK_ESCAPE) {
10028                       running = false;
10029                   }
... [90 more lines]

Grep (lua_pushcfunction|lua_register|setfield."engine_|lua_setglobal."engine_)

9064:    lua_register(L, "layer_create", l_layer_create);
9065:    lua_register(L, "layer_rectangle", l_layer_rectangle);
9066:    lua_register(L, "layer_rectangle_line", l_layer_rectangle_line);
9067:    lua_register(L, "layer_rectangle_gradient_h", l_layer_rectangle_gradient_h);
9068:    lua_register(L, "layer_rectangle_gradient_v", l_layer_rectangle_gradient_v);
9069:    lua_register(L, "layer_circle", l_layer_circle);
9070:    lua_register(L, "layer_circle_line", l_layer_circle_line);
9071:    lua_register(L, "layer_line", l_layer_line);
9072:    lua_register(L, "layer_capsule", l_layer_capsule);
9073:    lua_register(L, "layer_capsule_line", l_layer_capsule_line);
9074:    lua_register(L, "layer_triangle", l_layer_triangle);
9075:    lua_register(L, "layer_triangle_line", l_layer_triangle_line);
9076:    lua_register(L, "layer_polygon", l_layer_polygon);
9077:    lua_register(L, "layer_polygon_line", l_layer_polygon_line);
9078:    lua_register(L, "layer_rounded_rectangle", l_layer_rounded_rectangle);
9079:    lua_register(L, "layer_rounded_rectangle_line", l_layer_rounded_rectangle_line);
9080:    lua_register(L, "layer_push", l_layer_push);
9081:    lua_register(L, "layer_pop", l_layer_pop);
9082:    lua_register(L, "layer_draw_texture", l_layer_draw_texture);
9083:    lua_register(L, "layer_set_blend_mode", l_layer_set_blend_mode);
9084:    lua_register(L, "layer_stencil_mask", l_layer_stencil_mask);
9085:    lua_register(L, "layer_stencil_test", l_layer_stencil_test);
9086:    lua_register(L, "layer_stencil_test_inverse", l_layer_stencil_test_inverse);
9087:    lua_register(L, "layer_stencil_off", l_layer_stencil_off);
9088:    lua_register(L, "texture_load", l_texture_load);
9089:    lua_register(L, "texture_create", l_texture_create);
9090:    lua_register(L, "texture_unload", l_texture_unload);
9091:    lua_register(L, "texture_get_width", l_texture_get_width);
9092:    lua_register(L, "texture_get_height", l_texture_get_height);
9094:    lua_register(L, "spritesheet_load", l_spritesheet_load);
... [12 more lines]

Grep (l_engine_|engine_get_args|engine_quit)

111:static bool running = true;  // Main loop flag (file scope so engine_quit can access it)
8243:static int l_engine_get_frame(lua_State* L) {
8248:static int l_engine_get_step(lua_State* L) {
8253:static int l_engine_get_time(lua_State* L) {
8258:static int l_engine_get_dt(lua_State* L) {
8263:static int l_engine_get_unscaled_dt(lua_State* L) {
8268:static int l_engine_get_time_scale(lua_State* L) {
8273:static int l_engine_set_time_scale(lua_State* L) {
8278:static int l_engine_get_width(lua_State* L) {
8283:static int l_engine_get_height(lua_State* L) {
8288:static int l_engine_get_window_size(lua_State* L) {
8296:static int l_engine_get_scale(lua_State* L) {
8307:static int l_engine_is_fullscreen(lua_State* L) {
8313:static int l_engine_get_platform(lua_State* L) {
8322:static int l_engine_get_fps(lua_State* L) {
8327:static int l_engine_get_draw_calls(lua_State* L) {
8342:static int l_engine_mem_stats(lua_State* L) {
8424:static int l_engine_set_game_size(lua_State* L) {
8433:static int l_engine_set_title(lua_State* L) {
8444:static int l_engine_set_scale(lua_State* L) {
8452:static int l_engine_set_vsync(lua_State* L) {
8461:static int l_engine_set_fullscreen(lua_State* L) {
8466:static int l_engine_set_resizable(lua_State* L) {
8479:static int l_engine_set_render_uncapped(lua_State* L) {
8487:static int l_engine_set_display(lua_State* L) {
8496:static int l_engine_set_headless(lua_State* L) {
8504:static int l_engine_get_headless(lua_State* L) {
8509:static int l_engine_get_render_mode(lua_State* L) {
8514:static int l_engine_render_setup(lua_State* L) {
8552:static int l_engine_render_save_frame(lua_State* L) {
... [2 more lines]

Grep (l_engine_get_args|engine_get_args)

8731:static int l_engine_get_args(lua_State* L) {
9319:    lua_register(L, "engine_get_args", l_engine_get_args);

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

8731 static int l_engine_get_args(lua_State* L) {
8732        lua_newtable(L);
8733        for (int i = 0; i < cli_arg_count; i++) {
8734            lua_pushstring(L, cli_args[i].value);
8735            lua_setfield(L, -2, cli_args[i].key);
8736        }
8737        return 1;
8738    }
8739    
8740    static int l_engine_quit(lua_State* L) {
8741        (void)L;
8742        running = false;
8743        return 0;
8744    }
8745    
8746    // engine_init: Creates window and initializes graphics
8747    // Must be called from Lua (via framework) after configuration is set
8748    static int l_engine_init(lua_State* L) {
8749        if (engine_initialized) {
8750            return luaL_error(L, "engine_init can only be called once");
8751        }
8752    
8753        if (headless_mode) {
8754            // Headless: skip all graphics initialization
8755            printf("Headless mode: skipping window and graphics initialization\n");
8756            engine_initialized = true;
8757            printf("Engine initialized (headless): %dx%d\n", game_width, game_height);
8758            return 0;
8759        }
8760    
... [10 more lines]

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

10540                        error_state = true;
10541                   }
10542               } else {
10543                   lua_pop(L, 1);
10544               }
10545               step++;
10546               game_time += PHYSICS_RATE;
10547               // Post-update input state (needed for edge detection even if no real input)
10548               input_post_update();
10549           }
10550           lua_pop(L, 1);  // traceback
10551       } else if (render_mode) {
10552           // Render mode: deterministic loop — 2 physics steps per render frame, no real-time timing
10553           printf("Render loop starting...\n");
10554           lua_pushcfunction(L, traceback);
10555           int err_handler = lua_gettop(L);
10556           while (running && !error_state) {
10557               // Drain SDL events (so window stays responsive / closable)
10558               SDL_Event event;
10559               while (SDL_PollEvent(&event)) {
10560                   if (event.type == SDL_QUIT) {
10561                       running = false;
10562                   }
10563                   if (event.type == SDL_KEYDOWN && !event.key.repeat) {
10564                       if (event.key.keysym.sym == SDLK_ESCAPE) {
10565                           running = false;
10566                       }
10567                   }
10568               }
10569   
... [30 more lines]

80:static char window_title[256] = "Anchor";
97:static GLuint capture_fbo = 0;
98:static GLuint capture_texture = 0;
101:static char capture_output_dir[512] = "";
102:static FILE* record_pipe = NULL;  // Live recording: ffmpeg pipe for raw frame data
109:static struct { char key[MAX_CLI_KEY]; char value[MAX_CLI_VALUE]; } cli_args[MAX_CLI_ARGS];
159:static GLuint create_shader_program(const char* vert_src, const char* frag_src);
521:static PhysicsTag physics_tags[MAX_PHYSICS_TAGS];
531:static ShapeUserData shape_user_data_pool[MAX_SHAPE_USER_DATA];
545:static PhysicsTag* physics_tag_get(int index) {
551:static PhysicsTag* physics_tag_get_by_name(const char* name) {
621:static PhysicsContactBeginEvent contact_begin_events[MAX_PHYSICS_EVENTS];
624:static PhysicsContactEndEvent contact_end_events[MAX_PHYSICS_EVENTS];
627:static PhysicsHitEvent hit_events[MAX_PHYSICS_EVENTS];
630:static PhysicsSensorBeginEvent sensor_begin_events[MAX_PHYSICS_EVENTS];
633:static PhysicsSensorEndEvent sensor_end_events[MAX_PHYSICS_EVENTS];
647:static PCG32 global_rng = {0x853c49e6748fea9bULL, 0xda3e39cb94b95bdbULL, 0};
831:static Texture* texture_load(const char* path) {
884:static Texture* texture_create_from_rgba(int width, int height, const unsigned char* data) {
931:static Spritesheet* spritesheet_load(const char* path, int frame_width, int frame_height, int padding) {
1000:static FT_Library ft_library = NULL;
1003:static Font* font_registry[MAX_FONTS];
1045:static Font* font_load(const char* name, const char* path, float size, int font_filter) {
1254:static Font* font_get(const char* name) {
1303:static Sound* sound_load(const char* path) {

[Showing results with pagination = limit: 25]

Grep (mouse_buttons_current|keys_current[|MAX_MOUSE_BUTTONS)

2462:static bool keys_current[SDL_NUM_SCANCODES] = {0};
2466:#define MAX_MOUSE_BUTTONS 5
2467:static bool mouse_buttons_current[MAX_MOUSE_BUTTONS] = {0};
2468:static bool mouse_buttons_previous[MAX_MOUSE_BUTTONS] = {0};
2776:    memcpy(mouse_buttons_previous, mouse_buttons_current, sizeof(mouse_buttons_previous));
2992:        return ctrl->code >= 1 && ctrl->code <= MAX_MOUSE_BUTTONS;
3056:            return keys_current[ctrl->code];
3058:            if (ctrl->code >= 1 && ctrl->code <= MAX_MOUSE_BUTTONS) {
3059:                return mouse_buttons_current[ctrl->code - 1];
3087:            return keys_current[ctrl->code] && !keys_previous[ctrl->code];
3089:            if (ctrl->code >= 1 && ctrl->code <= MAX_MOUSE_BUTTONS) {
3091:                return mouse_buttons_current[idx] && !mouse_buttons_previous[idx];
3110:            return !keys_current[ctrl->code] && keys_previous[ctrl->code];
3112:            if (ctrl->code >= 1 && ctrl->code <= MAX_MOUSE_BUTTONS) {
3114:                return !mouse_buttons_current[idx] && mouse_buttons_previous[idx];
3605:    for (int i = 1; i <= MAX_MOUSE_BUTTONS; i++) {
7923:        lua_pushboolean(L, keys_current[scancode]);
7934:        lua_pushboolean(L, keys_current[scancode] && !keys_previous[scancode]);
7945:        lua_pushboolean(L, !keys_current[scancode] && keys_previous[scancode]);
7987:    if (button < 1 || button > MAX_MOUSE_BUTTONS) {

[Showing results with pagination = limit: 20]

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

2455 
2456    // ============================================================================
2457    // INPUT SYSTEM
2458    // Keyboard, mouse, gamepad state; action bindings; chords, sequences, holds
2459    // ============================================================================
2460    
2461    // Input state - Keyboard
2462    static bool keys_current[SDL_NUM_SCANCODES] = {0};
2463    static bool keys_previous[SDL_NUM_SCANCODES] = {0};
2464    
2465    // Input state - Mouse
2466    #define MAX_MOUSE_BUTTONS 5
2467    static bool mouse_buttons_current[MAX_MOUSE_BUTTONS] = {0};
2468    static bool mouse_buttons_previous[MAX_MOUSE_BUTTONS] = {0};
2469    static int mouse_x = 0, mouse_y = 0;           // Window coordinates
2470    static int mouse_dx = 0, mouse_dy = 0;         // Delta this frame
2471    static int mouse_wheel_x = 0, mouse_wheel_y = 0; // Wheel delta this frame
2472    
2473    // Input state - Global Hotkeys (Windows only)
2474    #ifdef _WIN32
2475    #define MAX_GLOBAL_HOTKEYS 16
2476    static struct {
2477        int id;
2478        bool fired;       // Set when WM_HOTKEY received, cleared in input_post_update
2479        bool registered;
2480    } global_hotkeys[MAX_GLOBAL_HOTKEYS];
2481    static int global_hotkey_count = 0;
2482    #endif
2483    
2484    // Input state - Gamepad
... [5 more lines]

Grep (SDL_CreateWindow|SDL_EventState)

8781:    window = SDL_CreateWindow(
8788:        return luaL_error(L, "SDL_CreateWindow failed: %s", SDL_GetError());

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

8780 
8781        window = SDL_CreateWindow(
8782            window_title,
8783            wpos, wpos,
8784            (int)(game_width * initial_scale), (int)(game_height * initial_scale),
8785            window_flags
8786        );
8787        if (!window) {
8788            return luaL_error(L, "SDL_CreateWindow failed: %s", SDL_GetError());
8789        }
8790    
8791        gl_context = SDL_GL_CreateContext(window);
8792        if (!gl_context) {
8793            return luaL_error(L, "SDL_GL_CreateContext failed: %s", SDL_GetError());
8794        }
8795    
8796        SDL_GL_SetSwapInterval((vsync_enabled && !render_mode) ? 1 : 0);
8797    
8798        #ifndef __EMSCRIPTEN__
8799        // Load OpenGL functions (desktop only - Emscripten provides them)
8800        int version = gladLoadGL((GLADloadfunc)SDL_GL_GetProcAddress);
8801        if (version == 0) {
8802            return luaL_error(L, "gladLoadGL failed");
8803        }
8804        printf("OpenGL %d.%d loaded\n", GLAD_VERSION_MAJOR(version), GLAD_VERSION_MINOR(version));

OK, ready to patch the engine. Four small additions; here's what they look like before I write:

1. State declarations (after line 2471, in the input-state block): c // Input state - Drag-and-drop file queue (bounded, drained per-frame by Lua) \#define MAX_DROPPED_FILES 32 \#define MAX_DROP_PATH_LEN 1024 static char dropped_files[MAX_DROPPED_FILES][MAX_DROP_PATH_LEN]; static int dropped_file_count = 0;

2. SDL event handler (in the main SDL_PollEvent loop, near line 10092 next to the window-event block): c // Track dropped files (OS drag-and-drop). SDL2 allocates event.drop.file; // we copy into a fixed buffer and free SDL's allocation immediately. if (event.type == SDL_DROPFILE) { if (dropped_file_count < MAX_DROPPED_FILES) { snprintf(dropped_files[dropped_file_count], MAX_DROP_PATH_LEN, "%s", event.drop.file); dropped_file_count++; } else { fprintf(stderr, "Warning: dropped file queue full (%d). Dropping path: %s\n", MAX_DROPPED_FILES, event.drop.file); } SDL_free(event.drop.file); }

3. Lua function (right after l_engine_quit, near line 8744): c // engine_get_dropped_files: returns paths dropped on the window since last call. // Drains the queue on read — caller is responsible for processing them. static int l_engine_get_dropped_files(lua_State* L) { lua_newtable(L); for (int i = 0; i < dropped_file_count; i++) { lua_pushstring(L, dropped_files[i]); lua_rawseti(L, -2, i + 1); } dropped_file_count = 0; return 1; }

4. Registration (near line 9319): c lua_register(L, "engine_get_dropped_files", l_engine_get_dropped_files);

Notes: SDL2 enables drop events by default so no explicit SDL_EventState needed. Bounded queue (32 paths, 1024 chars each) — same allocation discipline as the rest of the engine, no per-event malloc. SDL allocates event.drop.file for us and we must SDL_free it. "Drain on read" semantics: framework polls per frame, gets the list, processes it; next frame the queue is empty.

Writing the patches now.

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Now build the engine.

Bash (cd E:/a327ex/Anchor2/engine && ./build.bat 2>&1 | tail -30)

src/anchor.c(3237): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(3243): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(3353): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(3362): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(3456): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(3458): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(4695): warning C4996: 'strdup': The POSIX name for this item is deprecated. Instead, use the ISO C and C++ conformant name: _strdup. See online help for details.
src/anchor.c(5775): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(6660): warning C4244: 'initializing': conversion from 'lua_Number' to 'float', possible loss of data
src/anchor.c(6661): warning C4244: 'initializing': conversion from 'lua_Number' to 'float', possible loss of data
src/anchor.c(8434): warning C4244: '=': conversion from 'lua_Integer' to 'int', possible loss of data
src/anchor.c(8435): warning C4244: '=': conversion from 'lua_Integer' to 'int', possible loss of data
src/anchor.c(8441): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(8522): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9820): warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9824): warning C4996: 'strcat': This function or variable may be unsafe. Consider using strcat_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9829): warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9833): warning C4996: 'strcat': This function or variable may be unsafe. Consider using strcat_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9839): warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9843): warning C4996: 'strcat': This function or variable may be unsafe. Consider using strcat_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9849): warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(9853): warning C4996: 'strcat': This function or variable may be unsafe. Consider using strcat_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(10387): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(10389): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(10392): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
src/anchor.c(10395): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
gl.c
Generating Code...
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
Build successful: build/anchor.exe

Build succeeded — only pre-existing warnings, no new ones. Now I need to make sure the new engine binary lands at Anchor2/app/anchor.exe:

Bash (ls E:/a327ex/Anchor2/engine/build/anchor.exe E:/a327ex/Anchor2/app/anchor.exe E:...)

-rwxr-xr-x 1 adn 197121 4177408 Apr 17 10:27 E:/a327ex/Anchor2/app/anchor.exe
-rwxr-xr-x 1 adn 197121 4177408 Apr 17 10:31 E:/a327ex/Anchor2/arena/anchor.exe
-rwxr-xr-x 1 adn 197121 4180480 May 10 14:11 E:/a327ex/Anchor2/engine/build/anchor.exe
---
@echo off
setlocal

cd /d "%~dp0"

:: Find and run vcvarsall.bat for Visual Studio
if exist "C:\Program Files\Microsoft Visual Studio\18\Community\VC\Auxiliary\Build\vcvarsall.bat" (
    call "C:\Program Files\Microsoft Visual Studio\18\Community\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
) else if exist "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvarsall.bat" (
    call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
) else if exist "C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Auxiliary\Build\vcvarsall.bat" (
    call "C:\Program Files\Microsoft Visual Studio\2022\Professional\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
) else if exist "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" (
    call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul 2>&1
) else (
    echo ERROR: Could not find Visual Studio
    exit /b 1
)

if not exist build mkdir build

:: Build Lua library if it doesn't exist
if not exist lib\lua.lib (
    echo Building Lua library...
    if not exist build\lua_obj mkdir build\lua_obj
    cl.exe /nologo /O2 /W3 /c /I"include/lua" ^
... [79 more lines]

Bash (cat E:/a327ex/Anchor2/app/run.bat)

@echo off
REM Run the Anchor app. CWD must be repo root; first arg is the game folder name.

cd /d "%~dp0.."
"%~dp0anchor.exe" app

Bash (cp E:/a327ex/Anchor2/engine/build/anchor.exe E:/a327ex/Anchor2/app/anchor.exe &&...)

-rwxr-xr-x 1 adn 197121 4180480 May 10 14:11 E:/a327ex/Anchor2/app/anchor.exe
-rwxr-xr-x 1 adn 197121 4180480 May 10 14:11 E:/a327ex/Anchor2/arena/anchor.exe

To verify the engine plumbing works, I'll add a tiny temporary printf to app/main.lua's update — drop a file on the window, see the path printed to stdout. Then in sub-step 2 I'll replace this with the real canvas pane.

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Sub-step 1 is ready to test.

What you should see: Run cd E:/a327ex/Anchor2 && ./app/anchor.exe app (or app/run.bat). The window comes up identical to before (kit mode with the five panes). Drag any file from Explorer onto the window and drop it. Stdout should print [drop] C:\path\to\whatever.png. Drop multiple files at once — each gets a separate line. Drop a file, do nothing, then drop another — both lines appear at their respective drop times. Nothing visual changes inside the app yet.

What's actually wired:

Engine: SDL_DROPFILE events captured into a bounded 32-path queue, drained per call
Lua: engine_get_dropped_files() returns the list and clears the queue
App update(): drains the queue, prints each path

If anything's off (no print on drop, garbled paths with multibyte chars, app crash) that's an engine-side bug to chase. If it prints, sub-step 1 is done and I move on to the content store + canvas pane.

Paths are printing. Can you add support from dragging resources from the browser/Discord and so on, and not just explorer?

Good — sub-step 1 works for Explorer. Cross-source drag is a thicker subject. Let me lay out the reality before patching.

What SDL2 actually sees on Windows

When you drag from different apps, the OS exposes drops in different clipboard formats:

Source	Format	What SDL2 sees
Explorer	`CF_HDROP` (file path)	`SDL_DROPFILE` with the path ✓ already works
Chrome image	URL string + sometimes temp file	`SDL_DROPTEXT` with URL; sometimes also `SDL_DROPFILE`
Firefox image	Usually writes temp file first	`SDL_DROPFILE` (often works like Explorer)
Discord image	Cached to temp on drag start	Usually `SDL_DROPFILE`, sometimes nothing
Outlook attachment, virtual files	`CFSTR_FILEDESCRIPTOR` + `CFSTR_FILECONTENTS`	Nothing — SDL2 doesn't handle this format

So there are two layers of work:

Layer 1 — SDL_DROPTEXT (~15 lines, do now). Cheap. Captures URL/text payloads alongside file paths. After this, dragging a Chrome image at minimum gives us its URL string. Many drags from browsers/Discord will also produce SDL_DROPFILE because those apps write a temp file before the drop completes — those Just Work as files.

Layer 2 — actually fetching URLs (Track B HTTP client, hours of work). Pending engine addition from plan.md. Without it, URL drops come in as strings but we can't download them. With it, URL drop → HTTP fetch → content_store_put → blob → image element. This is a real detour I'd want to be explicit about before doing.

Layer 3 — virtual files (CFSTR_FILEDESCRIPTOR, more hours of Win32 OLE work). SDL2 doesn't handle this; we'd need to hook IDropTarget directly. Not recommending this now — it's only a few sources (Outlook, some chat apps) and a real platform-specific rabbit hole.

What I'd suggest

Do Layer 1 now. Then you test from Chrome / Firefox / Discord and we see what each app actually emits. Three possible outcomes:

Most drags come through as SDL_DROPFILE (browsers wrote temp files): we're already done, no HTTP client needed for the canvas pane MVP.
Critical drags come through as SDL_DROPTEXT with URLs: we know HTTP client is unavoidable and add it as part of Track B before sub-step 2.
Mixed: prioritize the case that hurts most.

Let me also unify the engine API while I'm at it — rename engine_get_dropped_files() → engine_get_drops() returning a list of {kind='file'|'text', value='...'} tables, since we now have two kinds.

Here's the updated patches before I write them:

State block (replaces the dropped_files block): ```c // Input state - Drag-and-drop queue (bounded, drained per-frame by Lua). // Holds both DROPFILE and DROPTEXT events in arrival order. #define MAX_DROPS 32 #define MAX_DROP_LEN 1024 typedef enum { DROP_KIND_FILE = 0, DROP_KIND_TEXT = 1 } DropKind; static struct { DropKind kind; char value[MAX_DROP_LEN]; } drops[MAX_DROPS]; static int drop_count = 0;

static void enqueue_drop(DropKind kind, const char* value) { if (drop_count < MAX_DROPS) { drops[drop_count].kind = kind; snprintf(drops[drop_count].value, MAX_DROP_LEN, "%s", value); drop_count++; } else { fprintf(stderr, "Warning: drop queue full (%d). Dropping %s: %s\n", MAX_DROPS, kind == DROP_KIND_FILE ? "file" : "text", value); } } ```

Event handler (replaces the DROPFILE-only block): c // Track OS drag-and-drop. SDL2 allocates event.drop.file (used for both // DROPFILE paths and DROPTEXT payloads); we copy and free immediately. if (event.type == SDL_DROPFILE) { enqueue_drop(DROP_KIND_FILE, event.drop.file); SDL_free(event.drop.file); } if (event.type == SDL_DROPTEXT) { enqueue_drop(DROP_KIND_TEXT, event.drop.file); SDL_free(event.drop.file); }

Lua function (replaces l_engine_get_dropped_files): c // engine_get_drops: returns list of {kind='file'|'text', value='...'} tables. // Drains the queue on read. static int l_engine_get_drops(lua_State* L) { lua_newtable(L); for (int i = 0; i < drop_count; i++) { lua_newtable(L); lua_pushstring(L, drops[i].kind == DROP_KIND_FILE ? "file" : "text"); lua_setfield(L, -2, "kind"); lua_pushstring(L, drops[i].value); lua_setfield(L, -2, "value"); lua_rawseti(L, -3, i + 1); } drop_count = 0; return 1; }

Writing now.

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Now update the temp printf in main.lua and rebuild:

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/engine && ./build.bat 2>&1 | tail -5 && cp build/anchor.exe...)

src/anchor.c(10417): warning C4996: 'strncpy': This function or variable may be unsafe. Consider using strncpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
gl.c
Generating Code...
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
Build successful: build/anchor.exe
Copied to app/ and arena/

Sub-step 1.5 ready to test.

What you should see: Same window as before. Drag from a few different places and watch stdout:

Explorer — same as before: [drop:file] C:\path\to\foo.png
Chrome image — likely either [drop:file] C:\Users\...\AppData\Local\Temp\... (Chrome wrote a temp file) or [drop:text] https://... (URL only) — sometimes both
Firefox image — usually [drop:file] with a temp path
Discord image — try dragging an image preview out of a message; usually [drop:file] with a temp path
Text selection from a browser/Discord — [drop:text] selected text content

The data we need from this round of testing:

Does anything print at all from each source?
For each source, what kind and what does the value look like?
Are temp-file paths actually readable when we try to open them later? (Some apps delete the temp file immediately after the drop completes — Discord can be guilty of this.)

If most image sources come through as file, we're already done with engine plumbing and I move on to sub-step 2 (content store + canvas pane). If critical sources only come through as text URLs, we've discovered we need the HTTP client first — that's a bigger conversation.

Drag from a few different places and report back what you see. No rush; the more sources you test the better we'll know what's possible.

Hm, currently it seems like I'm not able to drag resources from these apps and drop them in. The cursor shows a stop sign despite the link being visible and being dragged.

The stop sign means SDL's OLE drop target is rejecting those drags before the drop even begins. Let me check what SDL version is bundled and how it handles drop format registration.

Bash (ls E:/a327ex/Anchor2/engine/include/SDL2/ | head -20 && echo "---" && grep -r "S...)

begin_code.h
close_code.h
SDL.h
SDL_assert.h
SDL_atomic.h
SDL_audio.h
SDL_bits.h
SDL_blendmode.h
SDL_clipboard.h
SDL_config.h
SDL_config_android.h
SDL_config_emscripten.h
SDL_config_iphoneos.h
SDL_config_macosx.h
SDL_config_minimal.h
SDL_config_ngage.h
SDL_config_os2.h
SDL_config_pandora.h
SDL_config_windows.h
SDL_config_wingdk.h
---
\#define SDL_MAJOR_VERSION   2
\#define SDL_MINOR_VERSION   30
\#define SDL_PATCHLEVEL      10
    (x)->major = SDL_MAJOR_VERSION;                 \
    (x)->minor = SDL_MINOR_VERSION;                 \

Let me check what SDL source we have available and what drop formats it actually accepts.

Bash (find E:/a327ex/Anchor2/engine/ -name "SDL_windowsevents*" -o -name "SDL_dropeven...)

---
box2d.lib
freetype.lib
lua.lib
SDL2main.lib
SDL2-static.lib

This is a deeper issue than runtime config. Here's what I dug up:

What's actually happening

When you drag from Chrome / Firefox / Discord, the OS calls SDL's IDropTarget::DragEnter to ask "do you accept this?" SDL only checks for three formats: CF_HDROP (file paths), CF_UNICODETEXT, and CF_TEXT. If none match, SDL returns DROPEFFECT_NONE → the OS shows the stop sign.

The problem: at DragEnter time, modern browsers and chat apps don't offer those formats. They offer custom ones:

Chrome image drag: Chromium Internal Source URL, HTML Format, UniformResourceLocator (CFSTR_INETURL), and a virtual-file format. CF_UNICODETEXT is sometimes added later but not always at DragEnter.
Discord image drag: FileGroupDescriptorW + FileContents (a virtual file streamed from RAM). No file path on disk; SDL doesn't speak this format.
Firefox image drag: text/x-moz-url, application/x-moz-file-promise. Often also writes a temp file, which is why Firefox sometimes works.

So SDL 2.30 is rejecting the drop before any of our code runs. The SDL_EventState knobs don't help — they control event delivery, not which formats IDropTarget accepts.

Three honest options

A. Live with it. Only Explorer and apps-that-write-temp-files-first work. Workaround: save image to disk, drag from Explorer. Zero engine work, but it's a friction we'll feel forever.

B. Custom Win32 drop target (~200–300 lines of C, half a day). Call RevokeDragDrop on SDL's window to unhook SDL's handler, register our own IDropTarget that accepts:

CF_HDROP (files — same as today)
CF_UNICODETEXT (text/URLs — same as SDL would do)
CFSTR_INETURLW (Chrome/IE-style URL drags)
CFSTR_FILEDESCRIPTORW + CFSTR_FILECONTENTS (virtual files — Discord, Outlook, etc.)
CF_HTML as fallback (extract src= from img tag)

For virtual files, we'd extract the bytes via IDataObject::GetData → IStream → write to a temp path → emit as kind='file'. Discord drops would Just Work. Win32-only — Mac/Linux/Web would need separate implementations later, but those are non-issues for current daily use.

C. Patch SDL2 source and rebuild. SDL is open source; the relevant fix is ~50 lines in SDL_windowsevents.c. But the engine currently links lib/SDL2-static.lib precompiled — so we'd need to add SDL source-building to build.bat (the way Lua and Box2D already are). ~1–2 hours of build setup, then ~50 lines of patch. Same end result as B, but updating SDL upstream becomes painful (we'd carry our patch). Less control over format set than B.

My recommendation

B, but only if you actually want this now. It's half a day of focused Win32 work — not crushing but not the canvas-pane work itself, and it's the kind of yak-shave that can balloon. The honest tradeoff: B unblocks the natural workflow ("see image, drag, done") for every source you use; A means saving-to-disk first forever.

A reasonable middle path: stay on A for now, finish the canvas pane MVP with Explorer-only drops, then come back for B once the canvas is real and the friction is concrete. That way you build the actual feature first and can decide if cross-app drops are worth half a day after using the canvas a bit.

Or: if cross-app drops are the point of this exercise (and the canvas MVP is just the testbed), do B first.

Which way do you want to go?

Sure, let's leave this for later.

Moving to sub-step 2: content store + canvas pane.

Let me check a few prerequisites before implementing — what hashing the engine exposes, the existing image API, the placeholder pane structure I'll mirror.

Bash (ls E:/a327ex/Anchor2/app/panes/ && echo "---" && ls E:/a327ex/Anchor2/app/anchor...)

main.lua
panel.lua
status_bot.lua
status_top.lua
---
image.lua

Grep (^static int l.*hash|^static int l.sha|hash.Lua|HASH)

4725:static int l_set_draw_shader(lua_State* L);
4726:static int l_get_draw_shader(lua_State* L);
5453:static int l_shader_load_file(lua_State* L) {
5472:static int l_shader_load_string(lua_State* L) {
5490:static int l_shader_destroy(lua_State* L) {
5504:static int l_shader_set_float_immediate(lua_State* L) {
5514:static int l_shader_set_vec2_immediate(lua_State* L) {
5525:static int l_shader_set_vec4_immediate(lua_State* L) {
5538:static int l_shader_set_int_immediate(lua_State* L) {
5549:static int l_layer_shader_set_float(lua_State* L) {

[Showing results with pagination = limit: 10]

Read (E:\a327ex\Anchor2\app\anchor\image.lua)

1    --[[
2     image — thin wrapper for GPU texture handles.
3   
4     Usage:
5       images.player = image_load('player', 'assets/player.png')
6       layer_image(game_layer, images.player, 100, 100)
7   
8     An image is a plain table with .handle, .width, .height.
9   ]]
10  
11  image = class()
12  
13  function image:new(handle)
14    self.handle = handle
15    self.width = texture_get_width(handle)
16    self.height = texture_get_height(handle)
17  end
18  
19  -- Load a texture from a file, wrap it, and add to the global `images` table.
20  function image_load(name, path)
21    local handle = texture_load(path)
22    local img = image(handle)
23    if images then images[name] = img end
24    return img
25  end
26

Read (E:\a327ex\Anchor2\app\panes\panel.lua)

1    --[[
2     panel — generic bordered panel pane.
3   
4     Bg fill + 1px border (lavender if focused, subtle otherwise) + panel
5     header strip + centered hint text. Used as a stand-in for content
6     panes (file browser, agent, code editor, …) until those types are
7     written. Click anywhere in the pane to focus it; Ctrl+drag to move it
8     to another slot.
9   ]]
10  
11  pane_register_type('panel', {
12    init = function(self, opts)
13      self.title = opts.title or 'Panel'
14      self.hint  = opts.hint  or 'Ctrl+drag to swap with another slot.'
15    end,
16    update = function(self, dt, input, rect)
17      -- Focus is set by the workspace on click, uniformly across all panes
18      -- (see workspace.lua → update_focus_on_click). Pane types don't need
19      -- their own focus-on-click logic.
20  
21      -- Bg fill.
22      layer_rectangle(ui_layer, rect.x, rect.y, rect.w, rect.h, theme.bg_panel())
23  
24      -- 1px border, lavender when focused.
25      local border = pane_is_focused(self) and theme.lavender or theme.border_subtle
26      layer_rectangle(ui_layer, rect.x,             rect.y,             rect.w, 1,      border())
27      layer_rectangle(ui_layer, rect.x,             rect.y + rect.h - 1, rect.w, 1,      border())
28      layer_rectangle(ui_layer, rect.x,             rect.y,             1,      rect.h, border())
29      layer_rectangle(ui_layer, rect.x + rect.w - 1, rect.y,             1,      rect.h, border())
30  
... [14 more lines]

Grep (layer_image|layer_draw_texture|l_layer_image|l_layer_draw_texture)

E:\a327ex\Anchor2\app\anchor\image.lua:6:    layer_image(game_layer, images.player, 100, 100)
E:\a327ex\Anchor2\app\anchor\layer.lua:58:  draw_texture = layer_draw_texture,
E:\a327ex\Anchor2\app\anchor\layer.lua:169:function layer_image(lyr, img, x, y, color, flash)
E:\a327ex\Anchor2\framework\anchor\image.lua:6:    layer_image(game_layer, images.player, 100, 100)
E:\a327ex\Anchor2\framework\anchor\layer.lua:58:  draw_texture = layer_draw_texture,
E:\a327ex\Anchor2\framework\anchor\layer.lua:169:function layer_image(lyr, img, x, y, color, flash)
E:\a327ex\Anchor2\docs\ENGINE_API.md:196:### layer_draw_texture
E:\a327ex\Anchor2\docs\ENGINE_API.md:198:`layer_draw_texture(layer, texture, x, y, color?, flash?)`
E:\a327ex\Anchor2\docs\ENGINE_API.md:204:layer_draw_texture(layer, tex, player.x, player.y)
E:\a327ex\Anchor2\docs\ENGINE_API.md:205:layer_draw_texture(layer, tex, x, y, rgba(255, 100, 100), rgba(255, 255, 255, 128))  -- red tint + white flash
E:\a327ex\Anchor2\docs\ENGINE_API.md:243:layer_draw_texture(layer, tex, 150, 150)  -- only visible inside circle
E:\a327ex\Anchor2\docs\ENGINE_API_QUICK.md:26:layer_draw_texture(layer, texture, x, y, color?, flash?)
E:\a327ex\Anchor2\docs\FRAMEWORK_API_QUICK.md:250:layer_image(lyr, image, x, y, color?, flash?)
E:\a327ex\Anchor2\docs\FRAMEWORK_API.md:578:Draw with `layer_image(layer, image, x, y, color?, flash?)`.
E:\a327ex\Anchor2\docs\FRAMEWORK_API.md:726:layer_image(lyr, image, x, y, color?, flash?)

[Showing results with pagination = limit: 15]

Grep (l_layer_draw_texture|static int l_layer_draw_texture)

5403:static int l_layer_draw_texture(lua_State* L) {
5404-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5405-    Texture* tex = (Texture*)lua_touserdata(L, 2);
5406-    float x = (float)luaL_checknumber(L, 3);
5407-    float y = (float)luaL_checknumber(L, 4);
5408-    uint32_t color = (uint32_t)luaL_optinteger(L, 5, 0xFFFFFFFF);  // Default white (no tint)
5409-    uint32_t flash = (uint32_t)luaL_optinteger(L, 6, 0x00000000);  // Default black (no flash)
5410-    layer_add_image(layer, tex, x, y, color, flash);
5411-    return 0;
5412-}
5413-
5414-static int l_layer_set_blend_mode(lua_State* L) {
5415-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5416-    const char* mode = luaL_checkstring(L, 2);
5417-    if (strcmp(mode, "alpha") == 0) {
5418-        layer_set_blend_mode(layer, BLEND_ALPHA);
5419-    } else if (strcmp(mode, "additive") == 0) {
5420-        layer_set_blend_mode(layer, BLEND_ADDITIVE);
5421-    } else {
5422-        return luaL_error(L, "Invalid blend mode: %s (use 'alpha' or 'additive')", mode);
5423-    }
5424-    return 0;
5425-}
5426-
5427-// Stencil Lua bindings
5428-static int l_layer_stencil_mask(lua_State* L) {
5429-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5430-    layer_stencil_mask(layer);
5431-    return 0;
5432-}
... [43 more lines]

Grep (l_layer_push|l_layer_draw_spritesheet_frame)

5014:static int l_layer_push(lua_State* L) {
5015-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5016-    float x = (float)luaL_optnumber(L, 2, 0.0);
5017-    float y = (float)luaL_optnumber(L, 3, 0.0);
5018-    float r = (float)luaL_optnumber(L, 4, 0.0);
5019-    float sx = (float)luaL_optnumber(L, 5, 1.0);
5020-    float sy = (float)luaL_optnumber(L, 6, 1.0);
5021-    if (!layer_push(layer, x, y, r, sx, sy)) {
5022-        return luaL_error(L, "Transform stack overflow (max depth: %d)", MAX_TRANSFORM_DEPTH);
5023-    }
5024-    return 0;
5025-}
5026-
5027-static int l_layer_pop(lua_State* L) {
5028-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5029-    layer_pop(layer);
5030-    return 0;
5031-}
5032-
5033-static int l_texture_load(lua_State* L) {
5034-    const char* path = luaL_checkstring(L, 1);
5035-    Texture* tex = texture_load(path);
5036-    if (!tex) {
5037-        return luaL_error(L, "Failed to load texture: %s", path);
5038-    }
5039-    // Register for cleanup on shutdown
--
5133:static int l_layer_draw_spritesheet_frame(lua_State* L) {
5134-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5135-    Spritesheet* sheet = (Spritesheet*)lua_touserdata(L, 2);
... [32 more lines]

Read (E:\a327ex\Anchor2\app\anchor\layer.lua)

150  end
151 
152 function layer_rounded_rectangle(lyr, x, y, w, h, radius, color)
153   eng.rounded_rectangle(lyr_handle(lyr), x, y, w, h, radius, color)
154 end
155 
156 function layer_rounded_rectangle_line(lyr, x, y, w, h, radius, color, line_width)
157   eng.rounded_rectangle_line(lyr_handle(lyr), x, y, w, h, radius, color, line_width or 1)
158 end
159 
160 function layer_rectangle_gradient_h(lyr, x, y, w, h, color1, color2)
161   eng.rectangle_gradient_h(lyr_handle(lyr), x, y, w, h, color1, color2)
162 end
163 
164 function layer_rectangle_gradient_v(lyr, x, y, w, h, color1, color2)
165   eng.rectangle_gradient_v(lyr_handle(lyr), x, y, w, h, color1, color2)
166 end
167 
168 --- Image object (has .handle) or pass-through same as engine.
169 function layer_image(lyr, img, x, y, color, flash)
170   eng.draw_texture(lyr_handle(lyr), img.handle, x, y, color or 0xFFFFFFFF, flash or 0)
171 end
172 
173 --- Raw texture userdata / handle at x, y.
174 function layer_texture(lyr, tex, x, y, color)
175   eng.draw_texture(lyr_handle(lyr), tex, x, y, color or 0xFFFFFFFF, 0)
176 end
177 
178 function layer_spritesheet(lyr, sheet, frame, x, y, color, flash)
179   eng.draw_spritesheet_frame(lyr_handle(lyr), sheet.handle, frame, x, y, color or 0xFFFFFFFF, flash or 0)
... [10 more lines]

Grep (layer_add_image|void layer_add_image|^static void layer_add_image)

2041:static void layer_add_image(Layer* layer, Texture* tex, float x, float y, uint32_t color, uint32_t flash_color) {
2042-    DrawCommand* cmd = layer_add_command(layer);
2043-    if (!cmd) return;
2044-    cmd->type = COMMAND_SPRITE;
2045-    cmd->color = color;
2046-    cmd->flash_color = flash_color;
2047-    cmd->texture_id = tex->id;
2048-    cmd->params[0] = x;
2049-    cmd->params[1] = y;
2050-    cmd->params[2] = (float)tex->width;
2051-    cmd->params[3] = (float)tex->height;
2052-}
2053-
2054-// Pack two UV coordinates (0.0-1.0) into a float via bit reinterpretation (16 bits each)
2055-static float pack_uv_pair(float u, float v) {
2056-    uint16_t ui = (uint16_t)(u * 65535.0f);
2057-    uint16_t vi = (uint16_t)(v * 65535.0f);
2058-    uint32_t packed = ((uint32_t)ui) | ((uint32_t)vi << 16);
2059-    float result;
2060-    memcpy(&result, &packed, sizeof(float));
2061-    return result;
--
5410:    layer_add_image(layer, tex, x, y, color, flash);
5411-    return 0;
5412-}
5413-
5414-static int l_layer_set_blend_mode(lua_State* L) {
5415-    Layer* layer = (Layer*)lua_touserdata(L, 1);
5416-    const char* mode = luaL_checkstring(L, 2);
5417-    if (strcmp(mode, "alpha") == 0) {
... [2 more lines]

Grep (COMMAND_SPRITE)

378:    COMMAND_SPRITE,
379-    COMMAND_GLYPH,              // Font glyph with custom UVs (uses flash_color for packed UVs)
380:    COMMAND_SPRITESHEET_FRAME,  // Spritesheet frame with custom UVs and flash support
381-    COMMAND_LINE,               // Line segment / capsule
382-    COMMAND_TRIANGLE,           // Triangle (3 vertices)
383-    COMMAND_POLYGON,            // Polygon (up to 8 vertices)
384-    COMMAND_ROUNDED_RECTANGLE,  // Rounded rectangle
385-    COMMAND_RECTANGLE_GRADIENT_H, // Horizontal gradient rectangle (left to right)
386-    COMMAND_RECTANGLE_GRADIENT_V, // Vertical gradient rectangle (top to bottom)
387-    COMMAND_APPLY_SHADER,       // Post-process layer through a shader
388-    COMMAND_SET_UNIFORM_FLOAT,  // Set float uniform on shader
--
413:    uint8_t type;           // COMMAND_RECTANGLE, COMMAND_CIRCLE, COMMAND_SPRITE, COMMAND_APPLY_SHADER, COMMAND_SET_UNIFORM_*
414-    uint8_t blend_mode;     // BLEND_ALPHA, BLEND_ADDITIVE, BLEND_MULTIPLY
415-    uint8_t _pad[2];        // Padding to align next field to 4 bytes

[Showing results with pagination = limit: 15]

Grep (case COMMAND_SPRITE:)

4631:            case COMMAND_SPRITE:
4632-                process_sprite(cmd);
4633-                break;
4634-            case COMMAND_GLYPH:
4635-                process_glyph(cmd);
4636-                break;
4637-            case COMMAND_SPRITESHEET_FRAME:
4638-                process_spritesheet_frame(cmd);
4639-                break;
4640-            case COMMAND_STENCIL_MASK:
4641-                // Flush pending draws before changing stencil state
4642-                batch_flush();
4643-                // Enable stencil, write 1 to stencil buffer, don't draw to color
4644-                glEnable(GL_STENCIL_TEST);
4645-                glStencilFunc(GL_ALWAYS, 1, 0xFF);
4646-                glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);

Grep (^static void process_sprite)

4316:static void process_sprite(const DrawCommand* cmd) {
4317-    float x = cmd->params[0];
4318-    float y = cmd->params[1];
4319-    float w = cmd->params[2];
4320-    float h = cmd->params[3];
4321-
4322-    // Flush batch if texture changes
4323-    if (current_batch_texture != cmd->texture_id && batch_vertex_count > 0) {
4324-        batch_flush();
4325-    }
4326-    current_batch_texture = cmd->texture_id;
4327-
4328-    // Image is centered at (x, y), so compute corners
4329-    float half_w = w * 0.5f;
4330-    float half_h = h * 0.5f;
4331-
4332-    // Local corners (centered at x, y)
4333-    float lx0 = x - half_w, ly0 = y - half_h;
4334-    float lx1 = x + half_w, ly1 = y - half_h;
4335-    float lx2 = x + half_w, ly2 = y + half_h;
4336-    float lx3 = x - half_w, ly3 = y + half_h;
4337-
4338-    // Transform to world coordinates
4339-    float wx0, wy0, wx1, wy1, wx2, wy2, wx3, wy3;
4340-    transform_point(cmd->transform, lx0, ly0, &wx0, &wy0);
4341-    transform_point(cmd->transform, lx1, ly1, &wx1, &wy1);
--
4405:static void process_spritesheet_frame(const DrawCommand* cmd) {
4406-    float x = cmd->params[0];
4407-    float y = cmd->params[1];
... [23 more lines]

Grep (l_texture_load|static Texture* texture_load)

831:static Texture* texture_load(const char* path) {
832-    int width, height, channels;
833-    stbi_set_flip_vertically_on_load(0);  // Don't flip - we handle Y in our coordinate system
834-
835-    // Load file data from zip or disk
836-    size_t file_size;
837-    unsigned char* file_data = (unsigned char*)zip_read_file(path, &file_size);
838-    if (!file_data) {
839-        fprintf(stderr, "Failed to load texture: %s\n", path);
840-        return NULL;
841-    }
842-
843-    // Decode image from memory (needed for width/height even in headless)
844-    unsigned char* data = stbi_load_from_memory(file_data, (int)file_size, &width, &height, &channels, 4);
845-    free(file_data);
846-    if (!data) {
847-        fprintf(stderr, "Failed to decode texture: %s\n", path);
848-        return NULL;
849-    }
850-
851-    Texture* tex = (Texture*)malloc(sizeof(Texture));
852-    if (!tex) {
853-        stbi_image_free(data);
854-        return NULL;
855-    }
856-
--
5033:static int l_texture_load(lua_State* L) {
5034-    const char* path = luaL_checkstring(L, 1);
5035-    Texture* tex = texture_load(path);
... [22 more lines]

Grep (^[a-z].*zip_read_file|^char* zip_read_file|^void* zip_read_file)

278:static void* zip_read_file(const char* path, size_t* out_size) {
279-    // Try zip first if initialized
280-    if (zip_initialized) {
281-        // Try original path first
282-        void* data = mz_zip_reader_extract_file_to_heap(&zip_archive, path, out_size, 0);
283-        if (data) return data;
284-
285-        // PowerShell's Compress-Archive uses backslashes on Windows
286-        // Try with opposite separator if original path failed
287-        char alt_path[512];
288-        size_t len = strlen(path);
289-        if (len < sizeof(alt_path)) {
290-            strcpy(alt_path, path);
291-            for (char* p = alt_path; *p; p++) {
292-                if (*p == '/') *p = '\\';
293-                else if (*p == '\\') *p = '/';
294-            }
295-            data = mz_zip_reader_extract_file_to_heap(&zip_archive, alt_path, out_size, 0);
296-            if (data) return data;
297-        }
298-    }
--
340:static void* zip_read_file(const char* path, size_t* out_size) {
341-    FILE* f = fopen(path, "rb");
342-    if (!f) return NULL;
343-
344-    fseek(f, 0, SEEK_END);
345-    long size = ftell(f);
346-    fseek(f, 0, SEEK_SET);
347-
... [13 more lines]

Grep (^function sync_engine_globals|sync_engine_globals|mouse_x =|engine_get_mouse)

E:\a327ex\Anchor2\app\anchor\init.lua:20:      sync_engine_globals()          -- refresh time/frame/etc. mirrors
E:\a327ex\Anchor2\app\anchor\init.lua:84:  sync_engine_globals()
E:\a327ex\Anchor2\app\anchor\init.lua:97:function sync_engine_globals()
E:\a327ex\Anchor2\app\anchor\init.lua:146:  -- Set up dynamic global state (initial values; refreshed by sync_engine_globals)

Read (E:\a327ex\Anchor2\app\anchor\init.lua)

90     Note on dt: the `dt` parameter passed to your `update(dt)` function is
91    the UNSCALED fixed physics timestep (PHYSICS_RATE). If you want scaled
92    dt (e.g. during hitstop / slow-mo), compute `dt * time_scale` locally,
93    or call `engine_get_dt()` which returns the scaled version. We
94    deliberately do NOT set a global `dt` here to avoid shadowing the
95    function parameter inside update.
96  ]]
97  function sync_engine_globals()
98    frame_num = engine_get_frame()
99    step_num = engine_get_step()
100   time = engine_get_time()
101   unscaled_dt = engine_get_unscaled_dt()
102   window_width, window_height = engine_get_window_size()
103   scale = engine_get_scale()
104   fullscreen = engine_is_fullscreen()
105   fps = engine_get_fps()
106   draw_calls = engine_get_draw_calls()
107 end
108 
109 --[[
110   set_time_scale(scale)
111   Sets the engine-level time scale. Affects dt but not unscaled_dt.
112   Use unscaled_dt for things that should ignore slow-mo (UI, etc.).
113 ]]
114 function set_time_scale(s)
115   time_scale = s
116   engine_set_time_scale(s)
117 end
118 
119 -- The framework initialization function returned by require('anchor').
... [30 more lines]

Grep (engine_get_mouse|mouse_position|get_mouse)

E:\a327ex\Anchor2\app\anchor\camera.lua:209:  local mx, my = mouse_position()

Grep (^function mouse_)

No matches found

Grep (^function mouse|mouse_position)

E:\a327ex\Anchor2\app\anchor\camera.lua:209:  local mx, my = mouse_position()

Grep (mouse_position|mouse_pos|get_mouse)

E:\a327ex\Anchor2\app\anchor\camera.lua:209:  local mx, my = mouse_position()

Read (E:\a327ex\Anchor2\app\anchor\input.lua)

1    --[[
2     input — thin wrapper layer over the engine's built-in action binding system.
3   
4     The C engine provides input_bind/is_down/is_pressed/is_released/etc.
5     This module provides function wrappers that forward to those. Function
6     wrappers (instead of direct aliases) are used so that the engine C
7     functions are resolved at *call* time, not at module *load* time.
8     (The engine registers its functions during engine_init(), which runs
9     AFTER this module is loaded.)
10  
11    Usage:
12      bind('left', 'key:a')
13      bind('left', 'key:left')
14      bind('shoot', 'mouse:1')
15  
16      if input_down('left') then ... end
17      if input_pressed('shoot') then ... end
18  
19    Bind string format (parsed by the engine):
20      'key:<name>'    -- keyboard key (e.g., 'key:a', 'key:space', 'key:left')
21      'mouse:<num>'   -- mouse button (e.g., 'mouse:1' for left, 'mouse:2' for right)
22  ]]
23  
24  -- Registration
25  function bind(action, control) input_bind(action, control) end
26  function unbind(action, control) input_unbind(action, control) end
27  function unbind_all(action) input_unbind_all(action) end
28  function bind_chord(name, actions) input_bind_chord(name, actions) end
29  function bind_sequence(name, sequence) input_bind_sequence(name, sequence) end
30  function bind_hold(name, duration, source) input_bind_hold(name, duration, source) end
... [21 more lines]

Grep (l_mouse_position|"mouse_position"|mouse_get_position|mouse_x|mouse_y)

2469:static int mouse_x = 0, mouse_y = 0;           // Window coordinates
7974:static int l_mouse_position(lua_State* L) {
7976:    mouse_to_game_coords(mouse_x, mouse_y, &gx, &gy);
9292:    lua_register(L, "mouse_position", l_mouse_position);
10092:            mouse_x = event.motion.x;
10093:            mouse_y = event.motion.y;

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

7970     return 1;
7971    }
7972    
7973    // Mouse Lua bindings
7974    static int l_mouse_position(lua_State* L) {
7975        float gx, gy;
7976        mouse_to_game_coords(mouse_x, mouse_y, &gx, &gy);
7977        lua_pushnumber(L, gx);
7978        lua_pushnumber(L, gy);
7979        return 2;
7980    }
7981    
7982    static int l_mouse_delta(lua_State* L) {
7983        // Delta is in window pixels, scale to game pixels
7984        int window_w, window_h;

Grep (mouse_position|mouse_x|mouse_pos)

E:\a327ex\Anchor2\app\workspace.lua:143:  local mx, my = mouse_position()
E:\a327ex\Anchor2\app\workspace.lua:154:  local mx, my = mouse_position()
E:\a327ex\Anchor2\app\workspace.lua:211:  local mx, my = mouse_position()
E:\a327ex\Anchor2\app\workspace.lua:244:  local mx, my = mouse_position()
E:\a327ex\Anchor2\app\widgets.lua:65:  local mx, my = mouse_position()
E:\a327ex\Anchor2\app\anchor\camera.lua:209:  local mx, my = mouse_position()
E:\a327ex\Anchor2\app\docs\mockup_v2_code.html:916:          <div class="ln-row"><span class="ln">32</span><span class="gut"></span><span class="src"><span class="ind"></span><span class="k">local</span> <span class="v">mx</span>, <span class="v">my</span> <span class="o">=</span> <span class="f">mouse_position</span>()</span></div>
E:\a327ex\Anchor2\app\docs\ui_architecture.md:261:- Hit-tests the cursor against its rect using `mouse_position()`.

Read (E:\a327ex\Anchor2\app\workspace.lua)

135  end
136 
137 -- Focus-on-click: workspace-level, uniform across all panes. Click on a slot
138 -- → that slot's pane gets focus. Click outside any slot → focus clears.
139 -- Independent of Ctrl held: a Ctrl+click that starts a drag also focuses
140 -- the source pane, which gives the drag a useful visual anchor.
141 local function update_focus_on_click(rects)
142   if not mouse_is_pressed(1) then return end
143   local mx, my = mouse_position()
144   local slot = slot_at(rects, mx, my)
145   if slot then
146     pane_focus_id = workspace_state.slot_panes[slot]
147   else
148     pane_focus_id = nil
149   end
150 end
151 
152 -- Drag input handling. Mutates workspace_drag and (on drop) workspace_state.slot_panes.
153 local function handle_drag_input(rects)
154   local mx, my = mouse_position()
155 
156   if workspace_drag.state == 'idle' then
157     if mouse_is_pressed(1) and ctrl_held() then
158       local slot = slot_at(rects, mx, my)
159       if slot then
160         local r = rects[slot]
161         workspace_drag.state           = 'dragging'
162         workspace_drag.source_slot     = slot
163         workspace_drag.source_pane_id  = workspace_state.slot_panes[slot]
164         workspace_drag.cursor_offset_x = mx - r.x
... [20 more lines]

Read (E:\a327ex\Anchor2\app\workspace.lua)

220  end
221 
222 -- 2px lavender ring inside the drop-target slot rect (only when over a slot
223 -- different from the source).
224 local function paint_drop_highlight(rects)
225   if workspace_drag.state ~= 'dragging' then return end
226   local dst = workspace_drag.drop_slot
227   if not dst or dst == workspace_drag.source_slot then return end
228   local r = rects[dst]
229   if not r then return end
230   local c = theme.lavender
231   layer_rectangle(ui_layer, r.x,             r.y,             r.w, 2,    c())
232   layer_rectangle(ui_layer, r.x,             r.y + r.h - 2,   r.w, 2,    c())
233   layer_rectangle(ui_layer, r.x,             r.y,             2,   r.h,  c())
234   layer_rectangle(ui_layer, r.x + r.w - 2,   r.y,             2,   r.h,  c())
235 end
236 
237 -- 1px lavender outline of the source pane's size, anchored at the cursor
238 -- with the captured offset (the pane appears to be "held" at the same
239 -- relative cursor position where it was picked up).
240 local function paint_drag_ghost(rects)
241   if workspace_drag.state ~= 'dragging' then return end
242   local src_r = rects[workspace_drag.source_slot]
243   if not src_r then return end
244   local mx, my = mouse_position()
245   local gx = mx - workspace_drag.cursor_offset_x
246   local gy = my - workspace_drag.cursor_offset_y
247   local c = theme.lavender
248   layer_rectangle(ui_layer, gx,                  gy,                src_r.w, 1,        c())
249   layer_rectangle(ui_layer, gx,                  gy + src_r.h - 1,  src_r.w, 1,        c())
... [50 more lines]

Grep (STATE_FILE)

54:local STATE_FILE = '.workspace_state.lua'
293:-- Write the current workspace state to STATE_FILE. Called on every mutation
297:  local f, err = io.open(STATE_FILE, 'w')
318:-- Load STATE_FILE if present, validate against currently-registered modes /
328:  local f = io.open(STATE_FILE, 'r')

[Showing results with pagination = limit: 5]

I have everything I need. Writing three files now.

Write (E:\a327ex\Anchor2\app\content_store.lua)

File created successfully at: E:\a327ex\Anchor2\app\content_store.lua (file state is current in your context — no need to Read it back)

Write (E:\a327ex\Anchor2\app\panes\canvas.lua)

File created successfully at: E:\a327ex\Anchor2\app\panes\canvas.lua (file state is current in your context — no need to Read it back)

Now wire into main.lua:

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now remove the temporary drop-print loop — the canvas pane consumes drops itself:

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Read (E:\a327ex\Anchor2\app\workspace.lua)

315    f:close()
316 end
317 
318 -- Load STATE_FILE if present, validate against currently-registered modes /
319 -- panes / templates, populate workspace_state.per_mode with the survivors,
320 -- and switch to the saved active_mode if it's still valid. Returns the
321 -- name of the mode that ended up active, or nil if nothing could be loaded.
322 --
323 -- Validation drops silently: stale mode names, slot names not in the
324 -- current template, pane ids not in the registry. This means renaming a
325 -- pane in code falls back to the registered default for that slot, rather
326 -- than crashing on launch.
327 function workspace_load_state()
328   local f = io.open(STATE_FILE, 'r')
329   if not f then return nil end
330   local content = f:read('*all')
331   f:close()
332   local chunk, err = load(content, STATE_FILE, 't')
333   if not chunk then
334     io.stderr:write(('workspace_load_state: parse error: %s\n'):format(tostring(err)))
335     return nil
336   end
337   local ok, loaded = pcall(chunk)
338   if not ok or type(loaded) ~= 'table' then return nil end
339 
340   if type(loaded.per_mode) == 'table' then
341     for mode_name, slots in pairs(loaded.per_mode) do
342       local mode = workspace_modes[mode_name]
343       if mode and type(slots) == 'table' then
344         local tpl = workspace_templates[mode.template]
... [22 more lines]

Grep (^function rect_)

19:function rect_new(x, y, w, h)
24:function rect_cut_left(r, n)
30:function rect_cut_right(r, n)
34:function rect_cut_top(r, n)
40:function rect_cut_bot(r, n)
46:function rect_get_left(r, n)  return {x = r.x,            y = r.y,            w = n,   h = r.h} end
47:function rect_get_right(r, n) return {x = r.x + r.w - n,  y = r.y,            w = n,   h = r.h} end
48:function rect_get_top(r, n)   return {x = r.x,            y = r.y,            w = r.w, h = n}   end
49:function rect_get_bot(r, n)   return {x = r.x,            y = r.y + r.h - n,  w = r.w, h = n}   end
52:function rect_add_left(r, n)  return {x = r.x - n,    y = r.y,        w = n,   h = r.h} end
53:function rect_add_right(r, n) return {x = r.x + r.w,  y = r.y,        w = n,   h = r.h} end
54:function rect_add_top(r, n)   return {x = r.x,        y = r.y - n,    w = r.w, h = n}   end
55:function rect_add_bot(r, n)   return {x = r.x,        y = r.y + r.h,  w = r.w, h = n}   end
59:function rect_contract(r, t, ri, b, l)
63:function rect_expand(r, t, ri, b, l)
69:function rect_center(r, w, h)
75:function rect_split_h(r, n)
87:function rect_split_v(r, n)

Grep (slot_at|function rect_contains|point_in_rect)

121:local function point_in_rect(px, py, r)
122-  return px >= r.x and px < r.x + r.w and py >= r.y and py < r.y + r.h
123-end
124-
125--- Hit-test all slot rects against (mx, my). Returns slot name or nil.
126:local function slot_at(rects, mx, my)
127-  for name, r in pairs(rects) do
128:    if point_in_rect(mx, my, r) then return name end
129-  end
130-  return nil
131-end
132-
133-local function ctrl_held()
134-  return key_is_down('lctrl') or key_is_down('rctrl')
135-end
136-
--
144:  local slot = slot_at(rects, mx, my)
145-  if slot then
146-    pane_focus_id = workspace_state.slot_panes[slot]

[Showing results with pagination = limit: 20]

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Syntax-check the new Lua files before testing:

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK content_store.lua
OK panes/canvas.lua
OK main.lua

Quick headless sanity check to verify init doesn't crash:

Bash (cd E:/a327ex/Anchor2 && ./app/anchor.exe app --headless --verify 2>&1 | tail -20)

Anchor Engine starting...
Headless mode enabled
Game folder: app
Loading: main.lua
Headless mode: skipping window and graphics initialization
Engine initialized (headless): 1920x1080
Loaded font: sans_brand (12.0px, smooth) atlas=512x512
Loaded font: sans_label (10.0px, smooth) atlas=512x512
Loaded font: sans_body (14.0px, smooth) atlas=512x512
Loaded font: sans_uihead (16.0px, smooth) atlas=512x512
Loaded font: serif_body (14.0px, smooth) atlas=512x512
Loaded font: mono_tiny (10.0px, smooth) atlas=512x512
Loaded font: mono_small (11.0px, smooth) atlas=512x512
Loaded font: mono_body (13.0px, smooth) atlas=512x512
Created layer: ui (smooth)
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Bash (ls -la E:/a327ex/Anchor2/app/data/blobs/ 2>&1)

Exit code 2
ls: cannot access 'E:/a327ex/Anchor2/app/data/blobs/': No such file or directory

Bash (cd E:/a327ex/Anchor2 && cmd /c "if not exist \"app\data\blobs\" mkdir \"app\d...)

Exit code 2
Microsoft Windows [Version 10.0.26200.8246]
(c) Microsoft Corporation. All rights reserved.

E:\a327ex\Anchor2>ls: cannot access 'E:/a327ex/Anchor2/app/data/': No such file or directory

Bash (cd E:/a327ex/Anchor2 && cmd /c "if not exist \"app\data\blobs\" mkdir \"app\d...)

Exit code 2
Microsoft Windows [Version 10.0.26200.8246]
(c) Microsoft Corporation. All rights reserved.

E:\a327ex\Anchor2>ls: cannot access 'E:/a327ex/Anchor2/app/data/blobs/': No such file or directory

Bash (cd E:/a327ex/Anchor2 && cmd /c "mkdir app\data\blobs" 2>&1; ls -la E:/a327ex/A...)

Microsoft Windows [Version 10.0.26200.8246]
(c) Microsoft Corporation. All rights reserved.

E:\a327ex\Anchor2>

Bash (mkdir -p E:/a327ex/Anchor2/app/data/blobs && ls -la E:/a327ex/Anchor2/app/data/)

total 4
drwxr-xr-x 1 adn 197121 0 May 10 15:00 .
drwxr-xr-x 1 adn 197121 0 May 10 15:00 ..
drwxr-xr-x 1 adn 197121 0 May 10 15:00 blobs

Bash (rm -rf E:/a327ex/Anchor2/app/data && cd E:/a327ex/Anchor2 && cmd //c "mkdir app...)

blobs

The os.execute call wasn't working — cmd quoting through os.execute's shell wrapper is fragile. Let me simplify:

Bash (rm -rf E:/a327ex/Anchor2/app/data)

(Bash completed with no output)

Edit (E:\a327ex\Anchor2\app\content_store.lua)

The file E:\a327ex\Anchor2\app\content_store.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2 && ./app/anchor.exe app --headless --verify 2>&1 | tail -5 ...)

Exit code 2
Loaded font: mono_body (13.0px, smooth) atlas=512x512
Created layer: ui (smooth)
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...
ls: cannot access 'E:/a327ex/Anchor2/app/data/blobs/': No such file or directory

Let me add diagnostics to figure out what's failing:

Edit (E:\a327ex\Anchor2\app\content_store.lua)

The file E:\a327ex\Anchor2\app\content_store.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2 && ./app/anchor.exe app --headless --verify 2>&1 | grep -E ...)

[content_store] cwd test: package.config sep=\
[content_store] mkdir result: ok=nil kind=exit code=1
[content_store] probe open: file (0000024AF0365A90)

Bash (ls -la E:/a327ex/Anchor2/app/data/blobs/ 2>&1)

Exit code 2
ls: cannot access 'E:/a327ex/Anchor2/app/data/blobs/': No such file or directory

Bash (cd E:/a327ex/Anchor2 && /e/a327ex/Anchor/reference/love-compare/tools/lua54.exe ...)

result:  nil

Grep (l_io_|io_open_lua|loadlib|register_io|io.open)

No matches found

Grep (luaL_openlibs|liolib|\\"io\\"|io_lib)

10469:    luaL_openlibs(L);

Grep (SetCurrentDirectory|chdir|_chdir|game_folder|game_path)

26:#include <direct.h>  // _chdir
31:#include <unistd.h>  // chdir
10394:        const char* game_folder = NULL;
10420:            } else if (!game_folder && !zip_initialized) {
10421:                game_folder = argv[i];
10424:        if (game_folder) {
10426:            _chdir(game_folder);
10428:            chdir(game_folder);
10430:            printf("Game folder: %s\n", game_folder);

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

10390        }
10391   
10392       // Parse CLI arguments: first positional arg is game folder, --key=value are stored
10393       {
10394           const char* game_folder = NULL;
10395           for (int i = 1; i < argc; i++) {
10396               if (strcmp(argv[i], "--headless") == 0) {
10397                   headless_mode = true;
10398                   printf("Headless mode enabled\n");
10399               } else if (strcmp(argv[i], "--render") == 0) {
10400                   render_mode = true;
10401                   printf("Render mode enabled\n");
10402               } else if (strncmp(argv[i], "--", 2) == 0 && cli_arg_count < MAX_CLI_ARGS) {
10403                   // Parse --key=value or --key value
10404                   const char* arg = argv[i] + 2;  // skip "--"
10405                   const char* eq = strchr(arg, '=');
10406                   if (eq) {
10407                       int key_len = (int)(eq - arg);
10408                       if (key_len >= MAX_CLI_KEY) key_len = MAX_CLI_KEY - 1;
10409                       strncpy(cli_args[cli_arg_count].key, arg, key_len);
10410                       cli_args[cli_arg_count].key[key_len] = '\0';
10411                       strncpy(cli_args[cli_arg_count].value, eq + 1, MAX_CLI_VALUE - 1);
10412                       cli_args[cli_arg_count].value[MAX_CLI_VALUE - 1] = '\0';
10413                   } else {
10414                       strncpy(cli_args[cli_arg_count].key, arg, MAX_CLI_KEY - 1);
10415                       cli_args[cli_arg_count].key[MAX_CLI_KEY - 1] = '\0';
10416                       // Use "true" as default value for flags without =
10417                       strncpy(cli_args[cli_arg_count].value, "true", MAX_CLI_VALUE - 1);
10418                   }
10419                   cli_arg_count++;
... [20 more lines]

Bash (ls -la E:/a327ex/Anchor2/app/.workspace_state.lua 2>&1; ls -la E:/a327ex/Anchor2...)

Exit code 2
-rw-r--r-- 1 adn 197121 571 May 10 15:02 E:/a327ex/Anchor2/app/.workspace_state.lua
ls: cannot access 'E:/a327ex/Anchor2/.workspace_state.lua': No such file or directory

Bash (ls -la E:/a327ex/Anchor2/app/app/ 2>&1; find E:/a327ex/Anchor2/app -name ".probe...)

total 4
drwxr-xr-x 1 adn 197121 0 May 10 15:00 .
drwxr-xr-x 1 adn 197121 0 May 10 15:01 ..
drwxr-xr-x 1 adn 197121 0 May 10 15:00 data
E:/a327ex/Anchor2/app/app/data/blobs/.probe

Got it. The engine _chdir(game_folder)s into app/ on launch — confirmed by .workspace_state.lua living in app/. So my paths need to be relative to app/, not include the app/ prefix. Let me clean up the test artifacts and fix the code.

Bash (rm -rf E:/a327ex/Anchor2/app/app && ls E:/a327ex/Anchor2/app/ | head)

anchor
anchor.exe
assets
content_store.lua
design.md
docs
main.lua
pane.lua
panes
plan.md

Edit (E:\a327ex\Anchor2\app\content_store.lua)

The file E:\a327ex\Anchor2\app\content_store.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\content_store.lua)

The file E:\a327ex\Anchor2\app\content_store.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\content_store.lua)

The file E:\a327ex\Anchor2\app\content_store.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2 && ./app/anchor.exe app --headless --verify 2>&1 | tail -3 ...)

Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...
total 0
drwxr-xr-x 1 adn 197121 0 May 10 15:04 .
drwxr-xr-x 1 adn 197121 0 May 10 15:04 ..

Bash (cat E:/a327ex/Anchor2/app/.workspace_state.lua 2>&1)

-- Auto-generated by workspace.lua. Safe to delete to reset layouts.
return {
  active_mode = "bare",
  per_mode = {
    ["bare"] = {
      ["status_bot"] = "global_status_bot",
      ["status_top"] = "global_status_top",
    },
    ["compose"] = {
      ["status_bot"] = "global_status_bot",
      ["status_top"] = "global_status_top",
      ["main"] = "panel_a",
    },
    ["kit"] = {
      ["status_bot"] = "global_status_bot",
      ["status_top"] = "global_status_top",
      ["side_b"] = "panel_a",
      ["side_a"] = "panel_b",
    },
  },
}

Sub-step 2 is ready to test.

What you should see:

Run ./app/run.bat (or cd E:/a327ex/Anchor2 && ./app/anchor.exe app). Window comes up — and since your saved state put you in bare mode, the body is now one big canvas (with the top/bottom status bars). Drag any image from Explorer onto the canvas:

File gets hashed (FNV-1a 64) and copied into Anchor2/app/data/blobs/<16hex>.<ext>
An image element appears centered at the drop position, scaled down so the largest dimension is ≤ 600px
Stdout prints [canvas] added image blob:abc….png (1920x1080 → 600x337)
Drop the same image again → no second file on disk (dedup), but a new element shows up

Things worth poking at:

Drop multiple images in a row → they stack on top of each other at each drop position (no z-order yet, last drop wins overlap)
Drop a .txt or .pdf → [canvas] drop rejected: unsupported file type: txt to stdout, no element added
Switch modes (F1=kit, F2=compose, F3=bare) → canvas elements persist (same pane instance across modes); but in kit mode the canvas is sandwiched between the two side panels, so you'll only see the middle slice
Drop a file outside the canvas rect (e.g., onto the side panel in kit mode) → [canvas] drop outside canvas rect (file): ... to stdout, ignored
Browse Anchor2/app/data/blobs/ directly — should see one .png/.jpg/etc. per unique image you've dropped

What's NOT yet there (sub-step 3 next):

Click an image to select it
Drag-to-move
Persistence: close and reopen → elements are gone (the blobs are still on disk, but the (blob_id, x, y, w, h) list isn't saved yet)
Resize / delete / z-order

If the canvas renders, drops work, and dedup works, sub-step 2 is done.

If it's broken (no images appearing, crash on drop, weird positioning, images render at wrong size), report back and I'll chase. If it's good, I move on to sub-step 3.

I see no image being added currently. Before, the path displayed on the console, now it doesn't.

Read (E:\a327ex\Anchor2\app\workspace.lua)

1    --[[
2     workspace — the shell that hosts panes in slots defined by a template.
3   
4     Two registries + one piece of state:
5       workspace_templates  template name → ordered list of slot definitions
6       workspace_modes      mode name     → {template=<name>, panes={slot=pane_id, ...}}
7       workspace_state      active mode + cached resolved template + slot→pane map
8   
9     Templates are ordered arrays of slot defs. The order matters: edge slots
10    cut from the workspace rect one at a time in declaration order, then a
11    fill slot (if present) takes whatever's left. Each slot def is one of:
12  
13      {name='status_top', edge='top',    size=24}
14      {name='status_bot', edge='bottom', size=22}
15      {name='side_a',     edge='left',   size=320}
16      {name='side_b',     edge='right',  size=360}
17      {name='main',       fill=true}
18  
19    Modes bind specific pane ids to slot names. Two modes can share a
20    template — pane assignment is decoupled from layout.
21  
22    Per-frame work (called from main.lua's update(dt)):
23      1. workspace_compute_slot_rects() walks the template, returns
24         {slot_name → rect}.
25      2. For each (slot, pane_id) in the active mode's binding, look up the
26         pane in `panes` (from pane.lua) and call pane:update(dt, input,
27         slot_rect).
28  
29    Step 4 implements only this. Drag-to-swap (step 5), mode switching with
30    persistence (step 6), and splitter resize / free-form override
... [100 more lines]

Found it. The workspace state from sub-step 1 had main_placeholder in some slots, which got stripped during validation (since that pane no longer exists). For your bare mode specifically, the saved state has only status_top/status_bot — main is missing entirely, so the canvas pane never gets :update() called. That's why no drops show up: the canvas pane isn't even running.

There are two bugs converging:

Workspace doesn't fill in missing slots from registered defaults. When code adds new panes to a mode, they should appear automatically even with saved state. Currently they don't.
Once a slot is missing from saved state, it stays missing forever. The validation in workspace_load_state strips invalid pane refs but never re-fills with defaults.

Right architectural fix: change ensure_per_mode_state to merge defaults into existing state instead of skipping when state exists. Any slot not in saved state gets its registered default. User's drag-swaps stay intact (those slots ARE in saved state); new slots/panes get filled in.

Edit (E:\a327ex\Anchor2\app\workspace.lua)

The file E:\a327ex\Anchor2\app\workspace.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Clean. Re-test:

What you should see: Run ./app/run.bat. Since you were last in bare mode, the body is one big canvas region (status bar top + bottom, canvas in the middle). Drag any image from Explorer onto the canvas:

Stdout prints [canvas] added image blob:abc….png (WxH → wxh)
The image appears centered at the cursor position, scaled to fit ≤ 600px

If you switch to kit mode (F1), the canvas is now sandwiched between the two side panels — any images you've already dropped persist (same canvas pane instance), but you'll only see the middle slice. Drops onto the side panels print [canvas] drop outside canvas rect (file): ... and don't get added.

If you want to re-test with a clean slate, delete Anchor2/app/.workspace_state.lua first — that resets all modes to their registered defaults.

The underlying bug (slots stay missing forever once dropped from saved state) is fixed properly, not papered over. Any future code change that adds new panes to existing modes will Just Work for users with saved state.

Once I added an image the program crashed entirely, no Lua error even.

Hard crash with no Lua error means we're hitting C-side UB. Let me look at what could blow up in the render path.

Grep (layer_push.*bool|MAX_TRANSFORM_DEPTH)

366-
367-// Transform stack depth
368:#define MAX_TRANSFORM_DEPTH 32
369-
370-// Command queue capacity (fixed size, allocated once)
371-// 16384 commands × ~64 bytes = ~1MB per layer
372-#define MAX_COMMAND_CAPACITY 65536
373-
374-// Command types
375-enum {
376-    COMMAND_RECTANGLE = 0,
377-    COMMAND_CIRCLE,
378-    COMMAND_SPRITE,
379-    COMMAND_GLYPH,              // Font glyph with custom UVs (uses flash_color for packed UVs)
380-    COMMAND_SPRITESHEET_FRAME,  // Spritesheet frame with custom UVs and flash support
381-    COMMAND_LINE,               // Line segment / capsule
382-    COMMAND_TRIANGLE,           // Triangle (3 vertices)
383-    COMMAND_POLYGON,            // Polygon (up to 8 vertices)
384-    COMMAND_ROUNDED_RECTANGLE,  // Rounded rectangle
385-    COMMAND_RECTANGLE_GRADIENT_H, // Horizontal gradient rectangle (left to right)
386-    COMMAND_RECTANGLE_GRADIENT_V, // Vertical gradient rectangle (top to bottom)
387-    COMMAND_APPLY_SHADER,       // Post-process layer through a shader
388-    COMMAND_SET_UNIFORM_FLOAT,  // Set float uniform on shader
389-    COMMAND_SET_UNIFORM_VEC2,   // Set vec2 uniform on shader
390-    COMMAND_SET_UNIFORM_VEC4,   // Set vec4 uniform on shader
391-    COMMAND_SET_UNIFORM_INT,    // Set int uniform on shader
392-    COMMAND_SET_UNIFORM_TEXTURE, // Bind a texture to a sampler uniform
393-    COMMAND_STENCIL_MASK,       // Start writing to stencil buffer (don't draw to color)
--
473-    \ Each mat3: [m00 m01 m02 m10 m11 m12 m20 m21 m22]
... [12 more lines]

Grep (^bool layer_push|^static bool layer_push|^void layer_pop|^static void layer_pop)

2073:static bool layer_push(Layer* layer, float x, float y, float r, float sx, float sy);
2074:static void layer_pop(Layer* layer);
2075-
2076-// Record a glyph command (top-left positioned, with custom UVs from font atlas)
2077-// x, y is top-left corner of glyph; w, h is glyph size; UVs are atlas coordinates
2078-static void layer_add_glyph(Layer* layer, GLuint atlas_texture, float x, float y, float w, float h,
2079-                            float u0, float v0, float u1, float v1, uint32_t color) {
2080-    DrawCommand* cmd = layer_add_command(layer);
2081-    if (!cmd) return;
2082-    cmd->type = COMMAND_GLYPH;
2083-    cmd->color = color;
2084-    cmd->texture_id = atlas_texture;
2085-    cmd->params[0] = x;
2086-    cmd->params[1] = y;
2087-    cmd->params[2] = w;
2088-    cmd->params[3] = h;
2089-    cmd->params[4] = pack_uv_pair(u0, v0);  // 16-bit precision per component
2090-    cmd->params[5] = pack_uv_pair(u1, v1);
2091-}
2092-
2093-// Record a spritesheet frame command (centered at x, y, with custom UVs and flash support)
2094-static void layer_add_spritesheet_frame(Layer* layer, GLuint texture_id, float x, float y, float w, float h,
2095-                                        float u0, float v0, float u1, float v1,
2096-                                        uint32_t color, uint32_t flash_color) {
2097-    DrawCommand* cmd = layer_add_command(layer);
2098-    if (!cmd) return;
2099-    cmd->type = COMMAND_SPRITESHEET_FRAME;
--
2252:static bool layer_push(Layer* layer, float x, float y, float r, float sx, float sy) {
2253-    if (layer->transform_depth >= MAX_TRANSFORM_DEPTH - 1) {
... [51 more lines]

Grep (texture_load|TEXTURE_FILTER|tex.*filter|GL_LINEAR|GL_NEAREST)

831:static Texture* texture_load(const char* path) {
870:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
871:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
899:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
900:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
932:    Texture* tex = texture_load(path);
1044:// Also determines the atlas texture sampling filter (GL_NEAREST vs GL_LINEAR).
1208:        GLint tex_filter = (font_filter == FILTER_ROUGH) ? GL_NEAREST : GL_LINEAR;
1213:        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, tex_filter);
1214:        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, tex_filter);
1770:    GLint tex_filter = (layer_filter == FILTER_SMOOTH) ? GL_LINEAR : GL_NEAREST;
1781:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, tex_filter);
1782:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, tex_filter);
1848:    // Create effect texture (filter matches layer mode)
1849:    GLint tex_filter = (layer->filter_mode == FILTER_SMOOTH) ? GL_LINEAR : GL_NEAREST;
1853:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, tex_filter);
1854:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, tex_filter);
5033:static int l_texture_load(lua_State* L) {
5035:    Texture* tex = texture_load(path);
5064:    // Register for cleanup on shutdown (matches l_texture_load behavior).
8552:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
8553:    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
8664:        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
8665:        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
9130:    lua_register(L, "texture_load", l_texture_load);
9577:    "        // In smooth mode use the raw UV so the texture's linear filter (set at load\n"

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

855      }
856 
857     tex->width = width;
858     tex->height = height;
859 
860     if (headless_mode) {
861         // Headless: keep dimensions but skip GL texture upload
862         tex->id = 0;
863         stbi_image_free(data);
864         return tex;
865     }
866 
867     glGenTextures(1, &tex->id);
868     glBindTexture(GL_TEXTURE_2D, tex->id);
869     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
870     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
871     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
872     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
873     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
874     glBindTexture(GL_TEXTURE_2D, 0);
875     mem_gl_texture_count++;
876     mem_gl_texture_bytes += (size_t)width * (size_t)height * 4;
877 
878     stbi_image_free(data);
879     printf("Loaded texture: %s (%dx%d)\n", path, width, height);
880     return tex;
881 }
882 
883 // Create a texture from raw RGBA pixel data (4 bytes per pixel)
884 static Texture* texture_create_from_rgba(int width, int height, const unsigned char* data) {
... [5 more lines]

Read (E:\a327ex\Anchor2\app\anchor\class.lua)

1    --[[
2     class — minimal class helper for Anchor 2.
3   
4     Usage:
5       seeker = class()
6       function seeker:new(x, y)
7         self.x = x
8         self.y = y
9       end
10      function seeker:update(dt) ... end
11  
12      local s = seeker(10, 20)   -- calls seeker.new(instance, 10, 20)
13      s:update(dt)
14  
15    Notes:
16      - No inheritance. If you want a variant, copy the class and modify.
17      - Constructor is :new. If a class has no :new, calling the class still
18        returns an empty instance (useful for data-only classes).
19      - This is ~15 lines on purpose. Don't add features.
20  ]]
21  
22  function class()
23    local c = {}
24    c.__index = c
25    setmetatable(c, {
26      __call = function(cls, ...)
27        local instance = setmetatable({}, cls)
28        if cls.new then cls.new(instance, ...) end
29        return instance
30      end
... [4 more lines]

Grep (l_texture_get_width|^static int l_texture_get_width)

5088:static int l_texture_get_width(lua_State* L) {
5089-    Texture* tex = (Texture*)lua_touserdata(L, 1);
5090-    lua_pushinteger(L, tex->width);
5091-    return 1;
5092-}
5093-
5094-static int l_texture_get_height(lua_State* L) {
5095-    Texture* tex = (Texture*)lua_touserdata(L, 1);
5096-    lua_pushinteger(L, tex->height);
5097-    return 1;
5098-}
--
9133:    lua_register(L, "texture_get_width", l_texture_get_width);
9134-    lua_register(L, "texture_get_height", l_texture_get_height);
9135-    // --- Spritesheet ---
9136-    lua_register(L, "spritesheet_load", l_spritesheet_load);
9137-    lua_register(L, "spritesheet_get_frame_width", l_spritesheet_get_frame_width);
9138-    lua_register(L, "spritesheet_get_frame_height", l_spritesheet_get_frame_height);
9139-    lua_register(L, "spritesheet_get_total_frames", l_spritesheet_get_total_frames);
9140-    lua_register(L, "layer_draw_spritesheet_frame", l_layer_draw_spritesheet_frame);
9141-    // --- Font ---
9142-    lua_register(L, "font_load", l_font_load);
9143-    lua_register(L, "font_unload", l_font_unload);

I need to find exactly where the crash happens. Let me add aggressive diagnostic prints around each step — file IO, texture_load, image creation, and render — so the next test pinpoints the failing line:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Actually those render prints will flood — the update runs every frame. Let me make them fire just once per element by adding a flag:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Run it and drop one image. The console will print a trace of every step; whichever line is the LAST one printed before the crash is the one that crashed. Send me that output (and report whether the image actually appears for a moment before the crash, or whether the crash happens before any rendering).

If you don't have a console window visible (running as app/run.bat), launch from a terminal instead so you can see stdout:

cd E:/a327ex/Anchor2 && ./app/anchor.exe app

That way the trace prints stay on screen even if the executable dies. Drop one image, then paste me everything from [canvas] drop file: through to whatever the last line is before the crash.

You need to output things to a log because pasting an image kills everything immediately, including the console.

[Request interrupted by user]

Actually let me run it on the terminal.

Good plan — running from terminal directly is cleaner than debugging through a log file. The io.flush() after each print ensures the line hits stdout before the next operation, so whatever's the last line printed should be the crashing one.

Drop one image and paste me the trace. I'll wait.

Segmentation fault

Is all it said after default startup messages.

Found it. There's a stack bug in my engine code. When I refactored engine_get_drops() to return {kind=, value=} tables instead of bare strings, I got the Lua C API stack index wrong:

lua_rawseti(L, -3, i + 1);  // BUG: should be -2

Stack layout when this runs is [outer, inner] — only two entries. From the top, -1 is the inner table, -2 is the outer table. -3 is below the function's stack base — undefined behavior. In some configs Lua asserts; in this release build with assertions stripped, it casts garbage memory to a Table* pointer and writes through it. Either lucky-doesn't-crash (sub-step 1.5 testing) or instant segfault (now).

This is exactly the kind of bug a Lua API check build flag (LUA_USE_APICHECK) would catch, but Anchor's release build strips them.

Why it crashed now and not in sub-step 1.5: pure memory-layout luck. The garbage Table* happens to be a more-fatal pointer this time around. Heisenbug.

Fix is one character:

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/engine && ./build.bat 2>&1 | tail -3 && cp build/anchor.exe...)

Generating Code...
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
Build successful: build/anchor.exe
Engine rebuilt and copied

Engine rebuilt with the stack fix. Try dropping again — should not crash this time. The diagnostic prints I added are still in canvas.lua and will trace through each step. If it works, you'll see all the [canvas] drop file: / put done: / resolve done: / etc. lines, then the image should appear on the canvas.

If it still crashes (different crash this time would point to a separate bug — the file IO, texture load, or render path), the trace prints should show the last successful step before death.

[canvas] drop file: E:\media\anchor_6c4WBWvE7S.png [canvas] put done: id=blob:005230f61ece6ceb.png err=nil Loaded texture: data/blobs/005230f61ece6ceb.png (717x477) [canvas] resolve done: img=table: 00000249DC95A110 [canvas] img.width=717 img.height=477 img.handle=userdata: 00000249DA017570 [canvas] element added: pos=(147,458) size=(600,399) [canvas] render elem 1: handle=userdata: 00000249DA017570 pos=(147,458) size=(600,399) img.size=(717,477) [canvas] scale=(0.8368,0.8365), pushing transform [canvas] pushed; drawing texture Segmentation fault

Crash is between the trace lines pushed; drawing texture and drew; popping — so layer_draw_texture is what's crashing. Let me check what I'm actually passing — I think I'm calling the raw engine function with a wrapped layer object instead of going through the framework's wrapper:

Grep (^function layer_push|^function layer_draw_texture|^function layer_pop|lyr_handle|^local function lyr_handle)

31:  as a raw handle (see lyr_handle).
83:local function lyr_handle(lyr)
109:  eng.rectangle(lyr_handle(lyr), x, y, w, h, color)
113:  eng.circle(lyr_handle(lyr), x, y, radius, color)
117:  eng.rectangle_line(lyr_handle(lyr), x, y, w, h, color, line_width or 1)
121:  eng.circle_line(lyr_handle(lyr), x, y, radius, color, line_width or 1)
125:  eng.line(lyr_handle(lyr), x1, y1, x2, y2, width, color)
129:  eng.capsule(lyr_handle(lyr), x1, y1, x2, y2, radius, color)
133:  eng.capsule_line(lyr_handle(lyr), x1, y1, x2, y2, radius, color, line_width or 1)
137:  eng.triangle(lyr_handle(lyr), x1, y1, x2, y2, x3, y3, color)
141:  eng.triangle_line(lyr_handle(lyr), x1, y1, x2, y2, x3, y3, color, line_width or 1)
145:  eng.polygon(lyr_handle(lyr), vertices, color)
149:  eng.polygon_line(lyr_handle(lyr), vertices, color, line_width or 1)
153:  eng.rounded_rectangle(lyr_handle(lyr), x, y, w, h, radius, color)
157:  eng.rounded_rectangle_line(lyr_handle(lyr), x, y, w, h, radius, color, line_width or 1)
161:  eng.rectangle_gradient_h(lyr_handle(lyr), x, y, w, h, color1, color2)
165:  eng.rectangle_gradient_v(lyr_handle(lyr), x, y, w, h, color1, color2)
170:  eng.draw_texture(lyr_handle(lyr), img.handle, x, y, color or 0xFFFFFFFF, flash or 0)
175:  eng.draw_texture(lyr_handle(lyr), tex, x, y, color or 0xFFFFFFFF, 0)
179:  eng.draw_spritesheet_frame(lyr_handle(lyr), sheet.handle, frame, x, y, color or 0xFFFFFFFF, flash or 0)
184:    lyr_handle(lyr),
195:  eng.draw_text(lyr_handle(lyr), text, font_name, x, y, color)
198:function layer_push(lyr, x, y, r, sx, sy)
199:  eng.push(lyr_handle(lyr), x, y, r, sx, sy)
202:function layer_pop(lyr)
203:  eng.pop(lyr_handle(lyr))
207:  eng.set_blend_mode(lyr_handle(lyr), mode)
212:  eng.draw(lyr_handle(lyr), x or 0, y or 0)
216:  eng.apply_shader(lyr_handle(lyr), shader)
220:  eng.shader_set_float(lyr_handle(lyr), shader, name, value)
... [13 more lines]

Read (E:\a327ex\Anchor2\app\anchor\layer.lua)

1    --[[
2     Layer module — procedural API over the engine layer handle.
3   
4     Layers are FBOs that accumulate draw commands during the frame. Commands are
5     deferred and processed via layer_render() with GL batching. Composite to the
6     screen with layer_draw().
7   
8     Usage:
9       game_layer = layer_new('game')
10      layer_rectangle(game_layer, 100, 100, 50, 30, color)
11      layer_render(game_layer)
12      layer_draw(game_layer)
13  
14    State table shape (from layer_new): { name, handle, parallax_x, parallax_y }
15    All layer_* functions below take that table as the first argument `lyr`.
16  
17    ---------------------------------------------------------------------------
18    ENGINE NAME CONFLICTS (Lua globals registered by anchor.c)
19  
20    The C engine binds the same symbol names to raw engine implementations whose
21    first argument is a C layer pointer (lightuserdata), e.g. layer_rectangle(ptr, ...).
22  
23    This file captures those implementations in `eng` at load time, then REPLACES
24    the globals with wrappers whose first argument is a layer state table from
25    layer_new() (field .handle holds the pointer). Wrappers also accept a raw
26    handle for occasional interop.
27  
28    After require('anchor.layer'), direct engine-style calls like
29    layer_rectangle(userdata_ptr, x, y, w, h, c) no longer use the C binding
30    unless you passed a lightuserdata: the wrapper treats a non-table first arg
... [80 more lines]

Found the actual bug. There IS a framework wrapper for layer_push and layer_pop (in anchor/layer.lua), but no wrapper for layer_draw_texture — the global by that name is the raw C engine function, which expects a raw Layer* lightuserdata as arg 1. I was passing it ui_layer, which is the Lua table {name, handle, filter, ...} returned by layer_new. C's lua_touserdata returns NULL for tables → engine deref of NULL → segfault.

The framework provides two wrappers that handle this correctly: layer_image(lyr, img, x, y) (takes an image object) and layer_texture(lyr, tex, x, y) (takes a raw texture handle). Both shadow nothing — layer_draw_texture is just the unshadowed engine binding.

Why layer_push / layer_pop worked: those do have wrappers in layer.lua that accept the table and extract .handle.

This is exactly the kind of name-collision footgun the file's own header warns about (line 18: "ENGINE NAME CONFLICTS"). I missed it.

Fix: use layer_image instead. Same render outcome, correct first-arg handling.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Also remove the now-unneeded drop-side trace prints — we know that whole path works:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Clean. Try the drop again — should now render the image at the cursor position instead of crashing.

For the record on these two engine-binding gotchas (worth remembering for future panes):

layer_* functions split into two camps: those with framework wrappers in app/anchor/layer.lua (push, pop, rectangle, render, draw, image, texture, …) and those without (draw_texture, draw_spritesheet_frame, draw_text). Wrapped ones accept the table from layer_new; unwrapped ones expect raw lightuserdata. Easy to mix up because they share names with the engine globals.
Always go through wrappers when one exists — pass ui_layer (table), let the framework extract .handle. The unwrapped engine globals are an implementation detail you shouldn't depend on from app code.

The header in layer.lua actually warns about this; I should have read it more carefully before writing the canvas.

Perfect, images are loading now. They're not showing up in their original resolution though, I don't think. Not sure if that's intentional or not, but just letting you know.

That's my bug — I capped the size to 600px in the largest dimension as a defensive measure, but said "native size on drop, capped to fit the slot" in the spec. Those aren't the same thing. For a 717x477 screenshot dropped into a 1920x1034 slot, native is the right default; the 600px cap was overzealous.

Replacing the arbitrary cap with the slot-aware version: only scale down if the image is larger than the canvas rect, otherwise show at native size, aspect ratio preserved.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

1    --[[
2     canvas — free-flowing element canvas pane.
3   
4     Sub-step 2: drop image files onto the pane → saved to content store →
5     image element appears centered at the drop position, native size capped
6     to MAX_INITIAL_SIZE in the largest dimension. No selection/move yet.
7   
8     Element shape (in self.elements):
9       {type='image', blob_id='blob:<hex>.<ext>', image=<image>, x=, y=, w=, h=}
10  
11    blob_id is the persisted reference. `image` is the live texture handle
12    (re-resolved at load time in sub-step 3). x/y are top-left in window
13    coordinates (logical pixels).
14  
15    Drop routing note: drains engine_get_drops() directly. Fine while this
16    is the only drop-accepting pane; when a second one appears, drops
17    should route via the workspace based on cursor position.
18  ]]
19  
20  pane_register_type('canvas', {

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK

Try again — your 717x477 screenshot should now show at full native size since it fits comfortably inside the 1920x1034 canvas slot. Only oversized images (e.g., a 4K screenshot in this slot) get scaled down to fit, aspect ratio preserved.

If it looks right, sub-step 2 is done and I move on to sub-step 3 (selection + drag-to-move + persistence). One thing worth thinking about for sub-step 3 in case it changes the design:

Question for sub-step 3: if an image is larger than the canvas slot at drop time and gets shrunk to fit, that's a one-time decision. Do you want:

The shrink to be permanent — el.w / el.h are saved as the fitted size; future re-loads use the saved size; resizing handles (when added) operate on this size.
The shrink to be ephemeral — store el.w = nil / use native, render at fitted size on the fly. Resizing the canvas (e.g., switching modes) re-fits. User-initiated resize converts ephemeral → explicit size.

Option 1 is simpler. Option 2 preserves "I dropped a 4K image, when I move to a bigger window it should expand again" intuition. Honestly probably option 1 is fine — if the user wants the original-size, they can reset via a future "fit to native" command.

Just letting you think about it. Don't need to answer now — we can revisit when sub-step 3 starts.

What's substep 3 again? Only describe it to me.

Sub-step 3: Selection + drag-to-move + persistence

Three pieces, ~70–100 lines of Lua, no engine changes expected.

Selection. Click an image element → it becomes selected. Visual is a 1px lavender ring around the element bounds (same color as the focused-pane border, matches the UI kit's selection chrome). Click on empty canvas → deselect. Click on a different image → selection switches. Only one element selected at a time (multi-select can come later). State lives on the pane: self.selected_idx = N or nil.

Hit testing iterates elements in reverse order — the last-added element is drawn last (on top), so it should also be the first one a click selects. Standard rect-contains check.

Drag-to-move. Click+hold on the selected image → drag begins. Track the cursor offset from the image's top-left at drag start, then each frame while held: el.x = mouse_x - offset_x; el.y = mouse_y - offset_y. Release ends the drag.

The catch: the workspace already uses Ctrl+drag for moving panes between slots. The disambiguation is the modifier — plain drag = move image, Ctrl+drag = move pane. The workspace's drag handler runs first and only fires when Ctrl is held, so we just need to make sure we don't fire our drag when Ctrl is down. Easy enough.

Persistence. Save the canvas to app/data/canvases/scratch.lua as a Lua return-table:

return {
  version = 1,
  elements = {
    {type='image', blob_id='blob:<hex>.png', x=120, y=80, w=640, h=480},
    ...
  },
}

Note we save only blob_id + x/y/w/h — not the live image field (that's a userdata, can't be serialized). On load: read the file, walk elements, call content_store_resolve(blob_id) for each to re-attach the live image. Save triggers: on drop, on drag-end, on app exit. (Saving every frame during a drag would thrash the file uselessly.)

This is also where the document format starts. version = 1 lets us migrate later. Multiple canvases + canvas IDs come in step 7+8+9; for now there's one canvas, hardcoded path.

Two open design questions

You haven't answered these and they affect sub-step 3, so I'll lay them out:

1. The cap-to-fit shrink: permanent or ephemeral? When an oversize image is dropped and gets scaled down to fit the slot — should el.w/el.h save the fitted size, or save native and re-fit on every render?

Permanent (simpler): saved size is whatever fits at drop time. Resizing handles (when added) work on this. If you switch to a smaller slot later the image keeps its size and gets clipped/scrolls.
Ephemeral (more flexible): save native, re-fit each frame to current slot. Resizing the slot rescales the image. User-initiated resize converts ephemeral → explicit. More UX-correct, ~10 extra lines.

I'd default to permanent unless you have a strong opinion. Simpler now, easy to add ephemeral later via a "fit to native" command.

2. Constrain to slot, or free positioning with stencil clipping? You drag an image past the canvas edge — what happens?

Constrain: clamp el.x/el.y to slot bounds. Image can't leave the canvas. Simplest, but limits the mental model — every other canvas tool (Figma, Excalidraw, Miro) lets elements live wherever you put them.
Free positioning + stencil clipping: image keeps real coordinates, but rendering uses layer_stencil_mask to clip anything outside the canvas rect. Means the off-canvas part is invisible (won't render over side panels). When we add pan/scroll later, off-canvas elements become accessible naturally.

I'd default to free positioning with stencil clipping. It's the right mental model and the stencil setup is ~6 lines of wrapper around the element loop. Constraining now means undoing it later.

Pick a side on each (or "use your defaults") and I'll start sub-step 3.

Save native size. 2. Free positioning + stencil clipping.

[Request interrupted by user]

2 also solves 1, we don't need to actually resize the image, the user can do that automatically. Once the image spawns, it's full size, if it goes beyond the slot, the user can diminish it themselves. We can add keys later to automatically decrease an image's size in case the user can't click on the edges to decrease it with the mouse.

Got it — clipping subsumes shrinking. Cleaner. Spawn at native, let the canvas's stencil clip do the visual work, and resizing is the user's call (future keybinds for "make it smaller" cover the case where the image spawned bigger than the slot and you can't grab a corner).

These two changes go together — removing the shrink without adding the clip would let oversized images bleed into the side panels. Both at once is the right unit. The selection / drag-to-move / persistence pieces of sub-step 3 are bigger — I'll save those for a separate chunk after you confirm clipping works.

Let me first check how the stencil API actually behaves so I structure the calls right.

Grep (case COMMAND_STENCIL_MASK|case COMMAND_STENCIL_TEST|stencil_mask|^static int l_layer_stencil)

2112:static void layer_stencil_mask(Layer* layer) {
2113-    DrawCommand* cmd = layer_add_command(layer);
2114-    if (!cmd) return;
2115-    cmd->type = COMMAND_STENCIL_MASK;
2116-}
2117-
2118-// Queue stencil test command - subsequent draws only appear where stencil is set
2119-static void layer_stencil_test(Layer* layer) {
2120-    DrawCommand* cmd = layer_add_command(layer);
2121-    if (!cmd) return;
2122-    cmd->type = COMMAND_STENCIL_TEST;
2123-}
2124-
--
4640:            case COMMAND_STENCIL_MASK:
4641-                // Flush pending draws before changing stencil state
4642-                batch_flush();
4643-                // Enable stencil, write 1 to stencil buffer, don't draw to color
4644-                glEnable(GL_STENCIL_TEST);
4645-                glStencilFunc(GL_ALWAYS, 1, 0xFF);
4646-                glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
4647-                glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
4648-                break;
4649:            case COMMAND_STENCIL_TEST:
4650-                // Flush pending draws before changing stencil state
4651-                batch_flush();
4652-                // Only draw where stencil == 1
4653-                glStencilFunc(GL_EQUAL, 1, 0xFF);
4654-                glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
4655-                glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
... [7 more lines]

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

1    --[[
2     canvas — free-flowing element canvas pane.
3   
4     Sub-step 2: drop image files onto the pane → saved to content store →
5     image element appears centered at the drop position at native size.
6     If the image is larger than the canvas rect, it's scaled down (aspect
7     ratio preserved) to fit; otherwise no scaling. Never scaled up. No
8     selection/move yet.
9   
10    Element shape (in self.elements):
11      {type='image', blob_id='blob:<hex>.<ext>', image=<image>, x=, y=, w=, h=}
12  
13    blob_id is the persisted reference. `image` is the live texture handle
14    (re-resolved at load time in sub-step 3). x/y are top-left in window
15    coordinates (logical pixels).
16  
17    Drop routing note: drains engine_get_drops() directly. Fine while this
18    is the only drop-accepting pane; when a second one appears, drops
19    should route via the workspace based on cursor position.
20  ]]
21  
22  pane_register_type('canvas', {
23    init = function(self, opts)
24      self.elements = {}
25    end,
26  
27    update = function(self, dt, input, rect)
28      -- Process drops. Only consume drops when the cursor is inside the
29      -- canvas rect — drops elsewhere on the window get logged and ignored.
30      local mx, my = mouse_position()
... [63 more lines]

Now the edit — remove the shrink, add stencil clipping, update the header:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Test:

What you should see now:

Drop your 717x477 screenshot → renders at exactly 717x477 (centered at cursor) instead of 599x399. Console prints [canvas] added image ... (717x477 at native).
Drop a 4K image (or anything bigger than the slot) → it spawns at native size, clipped by the canvas rect. The visible portion is whatever overlaps the slot. Position the cursor toward the canvas center on drop and you'll see the middle of the image; toward an edge and you'll see that corner with the rest cut off.
In kit mode (F1), drop something at the boundary between the canvas and a side panel → the image's overflow is clipped at the canvas edge instead of drawing on top of the side panel.

One thing I'm slightly uncertain about: the engine's stencil buffer isn't explicitly cleared between frames. If anything else on this frame happened to write to the stencil before we got here, our test could pick up stray bits. Right now nothing else uses stencil so it should be fine, but if you see weird visual artifacts (wrong areas getting clipped, or images visible where they shouldn't be), that's the suspect — we'd need to add an explicit clear at the start of our mask. Mention it if you see anything strange.

Once you confirm clipping looks right, the next chunk is the real meat of sub-step 3: selection + drag-to-move + persistence.

Clipping looks right.

Starting sub-step 3 in three chunks:

3a (now): Selection — click to select topmost, click empty to deselect, lavender ring on the selected element.
3b: Drag-to-move on the selected element.
3c: Persistence — save/load canvas to data/canvases/scratch.lua.

For 3a:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

1    --[[
2     canvas — free-flowing element canvas pane.
3   
4     Sub-step 2: drop image files onto the pane → saved to content store →
5     image element appears centered at the drop position at NATIVE pixel
6     size. Oversize images overflow the slot intentionally; the stencil
7     clip below hides anything outside the canvas rect, so overflow doesn't
8     bleed into neighboring panes. Resizing/repositioning is the user's
9     call (sub-step 3 will add selection + drag-to-move; future keybinds
10    will handle "make smaller" for cases where the image spawns too big
11    to grab a corner of).
12  
13    Element shape (in self.elements):
14      {type='image', blob_id='blob:<hex>.<ext>', image=<image>, x=, y=, w=, h=}
15  
16    blob_id is the persisted reference. `image` is the live texture handle
17    (re-resolved at load time in sub-step 3). x/y are top-left in window
18    coordinates (logical pixels). w/h start at native image size and stay
19    there until the user resizes.
20  
21    Drop routing note: drains engine_get_drops() directly. Fine while this
22    is the only drop-accepting pane; when a second one appears, drops
23    should route via the workspace based on cursor position.
24  ]]
25  
26  -- Returns the index of the topmost element containing (px, py), or nil.
27  -- Topmost = last in self.elements (drawn last, so visually on top).
28  local function hit_test(elements, px, py)
29    for i = #elements, 1, -1 do
30      local el = elements[i]
... [103 more lines]

Now add the selection ring after the elements loop, inside the stencil block:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

3a is ready.

What you should see:

Drop a few images. Click on one → 1px lavender ring traces its bounds. Click on another → ring moves to that one.
Click on empty canvas → ring disappears (deselect).
If two images overlap, clicking on the overlap selects the topmost (= the most recently dropped, which draws on top).
Ctrl+click on the canvas: workspace's pane-swap drag fires; canvas selection logic skips it. So the ring shouldn't change just from holding Ctrl during a click.
An image positioned partially off-canvas: the ring is also clipped at the canvas edge (since it's inside the stencil block). Correct behavior.
Switch modes (F1/F2/F3): selection state is on the pane, so it persists. Switch back to a mode where the canvas is in main and the ring is still on whatever was selected.

What it can't do yet — clicking on a selected element does nothing beyond keeping it selected. Drag-to-move is 3b.

Confirm the ring shows where you expect, then I'll do drag-to-move.

Everything seems good.

3b: drag-to-move.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

3b ready.

What you should see:

Click an image → selected (lavender ring), AND drag starts automatically. Move the cursor → image follows.
Release mouse → drag ends; image stays where you released.
Click empty canvas → deselect, no drag.
Click on a different image → switches selection AND starts dragging the new one.
Two overlapping images: clicking on the overlap drags the topmost.
Dragging an image partially off-canvas: free positioning, stencil clips the off-canvas portion. Element's real coordinates go off the slot rect, but visually only the in-canvas part shows. (Confirms the stencil correctness from 3a.)
Ctrl+drag still moves panes between slots — canvas drag doesn't fire when Ctrl is held.

One known limitation (not a bug, just inherent to SDL): if you drag the cursor outside the window during a drag, the mouse position freezes at the last in-window position — the image gets stuck at the window edge until you bring the cursor back. Same limitation the workspace's pane-drag has. Fixable later with SDL_CaptureMouse if it bites.

If drag feels right, I move on to 3c (persistence).

Everything seems to work. Before persistence, can we add scaling with the mouse? Dragging one of the corners scales the image appropriately. Should also have little squares on each of the corners. And top/bottom/left/right edges should also be draggable to decrease the image along those directions (maintaining aspect ratio).

Sure. Let me think through the design before applying.

Visual design:

4 small lavender squares centered on each corner of the selected element (8×8 px).
Edges are draggable but no visible squares — hit zones only. (I can add midpoint edge squares later if discoverability becomes an issue; standard tools like Figma show 8 handles total, but you said corners only, so going with that.)

Hit-test priority on click (when an element is already selected):

Corner handles (12×12 hit zone, slightly larger than the 8×8 visible square for grabbability)
Edge bands (6 px thick along each edge, between the corner zones)
Body — falls through to the existing select/move logic

Resize math, all aspect-preserving:

Corner drag — opposite corner stays fixed (the "anchor"). New scale = max(desired_w / orig_w, desired_h / orig_h) so the cursor leads the resize on whichever axis you drag faster; the orthogonal dimension catches up. New w = orig_w × scale, new h = orig_h × scale. el.x / el.y recomputed to keep the anchor corner pinned.
Edge drag — opposite edge stays fixed; the orthogonal axis stays centered on its pre-drag center. So dragging the right edge: left edge pins, vertical center pins (top moves up + bottom moves down by half the height delta each). Scale = desired_w / orig_w (or desired_h / orig_h for vertical edges).

Edges allow both shrink and grow, despite your wording emphasizing decrease — that's the symmetric, more useful behavior. Easy to constrain to decrease-only later if you want.

Other:

Minimum size: 16 px. Below that, the corner squares stop being grabbable.
orig_w / orig_h are captured at click-start, not the live element dims. Each fresh click starts a fresh resize with current dims as the new "orig". Drag-then-release-then-drag-again works the way you'd expect.
All resize-state lives in self.drag alongside the existing move-state. State machine: 'idle' | 'moving' | 'resizing' (the old 'dragging' becomes 'moving').

Applying now.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now add the corner squares to the rendering block:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Update the docstring to reflect the new capabilities:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Resize handles ready to test.

What you should see:

Drop an image → click it → selected (lavender ring + 4 corner squares appear).
Drag a corner square → aspect-preserving resize. Drag bottom-right outward → grow; drag inward toward top-left → shrink. Top-left corner pin stays fixed (drag bottom-right). The other three corners work analogously — opposite corner stays put.
Drag an edge (a 6px band between the corner squares; not visually marked) → aspect-preserving scale anchored on the opposite edge midpoint. Drag the right edge rightward → grows; leftward → shrinks. Top/bottom of the image move symmetrically (stays vertically centered relative to its pre-drag center). Equivalent for the other 3 edges.
Resize speed: corner drag uses max(dw, dh) scale, so whichever axis you move the cursor faster on leads. The cursor doesn't stay exactly on the dragged corner — there's a small visual lag in the orthogonal direction. (The trade-off of strict aspect preservation; matches Photoshop's Shift+drag behavior.)
Minimum size: 16 px. Drag past the anchor and the element clamps at 16×(aspect ratio).
Click element body → still selects + starts moving (existing 3a/3b behavior, untouched).
Ctrl+drag → still swaps panes between slots.

Things to look out for:

If a corner square sits over the canvas edge, it gets stencil-clipped and is hard to grab. Move the element inward first or we add a "shrink" keybind later.
Edge bands have no visible marker — let me know if discoverability is annoying and I'll add midpoint squares (would make 8 visible handles total, standard convention).

If resize feels right, the next chunk is 3c (persistence: save/load on disk).

Make the squares be inside the image itself, never outside. Also draw the edge markers. And change the cursor to the usual dragging cursor instead of normal one when the mouse is over a portion that will resize the image.

Three things to do. Two are pure Lua (move squares inside + add edge midpoint squares); the cursor change needs an engine addition since there's no cursor API yet. Let me start with the engine change.

Grep (SDL_SetCursor|SDL_CreateSystemCursor|l_engine_set_title)

8456:static int l_engine_set_title(lua_State* L) {
9344:    lua_register(L, "engine_set_title", l_engine_set_title);

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

8456 static int l_engine_set_title(lua_State* L) {
8457        const char* title = luaL_checkstring(L, 1);
8458        strncpy(window_title, title, sizeof(window_title) - 1);
8459        window_title[sizeof(window_title) - 1] = '\0';
8460        // If window already exists, update title immediately
8461        if (window) {
8462            SDL_SetWindowTitle(window, window_title);
8463        }
8464        return 0;
8465    }
8466    
8467    static int l_engine_set_scale(lua_State* L) {
8468        if (engine_initialized) {
8469            return luaL_error(L, "engine_set_scale must be called before engine_init");
8470        }
8471        initial_scale = (float)luaL_checknumber(L, 1);
8472        return 0;
8473    }
8474    
8475    static int l_engine_set_vsync(lua_State* L) {
8476        vsync_enabled = lua_toboolean(L, 1);
8477        // If window already exists, apply immediately
8478        if (window) {
8479            SDL_GL_SetSwapInterval(vsync_enabled ? 1 : 0);
8480        }

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/engine && ./build.bat 2>&1 | tail -3 && cp build/anchor.exe...)

Generating Code...
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
Build successful: build/anchor.exe
Engine rebuilt

Engine has cursor support now. Updating canvas.lua: move handles inside, add edge midpoint squares, add cursor logic.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the rendering — replace the corner-square drawing with the inside-the-image version + edge midpoint squares:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the cursor logic — set the cursor each frame based on hover/drag state:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Ready to test.

What you should see:

Select an image → 8 lavender squares appear: 4 at the corners + 4 at the edge midpoints, all inside the image. The squares are anchored to their respective edge/corner, growing inward.
Hover over a corner square → cursor switches to the diagonal resize arrow (↖↘ for TL/BR, ↗↙ for TR/BL). Hover over an edge handle → horizontal or vertical resize arrow. Hover anywhere else in the canvas → normal arrow.
During an active resize, the cursor stays on the resize arrow even if you move outside the handle (until you release).
Resize behavior is identical to before — corners aspect-preserve via opposite corner pin, edges aspect-preserve via opposite edge + orthogonal center pin.

A few details:

Minimum size is now 24×24 (was 16×16) so the corner squares have room without overlapping diagonally. Existing elements smaller than 24 in your canvas keep their current size; only fresh resizes clamp at 24.
Edge midpoint squares only appear when the element is at least 24 in the relevant dimension (s*3 = 24 — corner + midpoint + corner with no gap). At exactly 24 they tile flush against the corners; for larger elements there's a visible gap. If the image is too narrow but tall enough, you'll see midpoints on left/right but not top/bottom (and vice versa).
Resize chrome lives inside the stencil clip, like the rest of the selection chrome. The handles are inside the image so they're never fully clipped at the canvas edge — at worst they're at the canvas border alongside the image, still grabbable.

If you find the squares are too small (8 px) to comfortably grab, let me know and I'll bump HANDLE_SIZE. Same for EDGE_HIT if the edge bands feel finicky.

If everything looks right and cursors switch as expected, I'll move on to 3c (persistence).

Perfect, tell me what you'll do in the next step first.

Sub-step 3c: Persistence

Save canvas state to disk so it survives app restarts. Round trip: drop image → close app → reopen → image is exactly where you left it, same size, same blob.

File layout: app/data/canvases/scratch.lua — single hardcoded canvas for now. Multi-canvas support (with stable IDs) is part of step 7+8+9 — too early to bake in.

File format: Lua return-table, same style as .workspace_state.lua. Hand-readable, hand-editable for emergencies:

-- Auto-generated by canvas.lua. Safe to delete to reset.
return {
  version = 1,
  elements = {
    {type="image", blob_id="blob:005230f61ece6ceb.png", x=120, y=80, w=717, h=477},
    {type="image", blob_id="blob:a3fe...png", x=900, y=400, w=320, h=240},
  },
}

What's persisted per element: type, blob_id, x, y, w, h. What's NOT: the live image (texture userdata — can't serialize), selected_idx, drag state (both ephemeral).

Load flow (in pane init):

Try to read data/canvases/scratch.lua. File missing → fresh empty canvas (no error).
Parse error → log to stderr, fresh canvas (don't crash).
For each saved element: call content_store_resolve(blob_id) to re-attach the live image, then push into self.elements. If the blob can't be resolved (file got deleted out from under us) → skip the element with a warning, don't crash.

Save triggers:

After every successful drop (new element added)
When a drag/resize ends (mouse_is_released while drag state was non-idle)
NOT every frame during a drag — would thrash disk for no reason

No explicit "on app exit" save needed — since every mutation saves immediately, the file is always current. If the app crashes mid-drag, the element snaps back to its last-saved position on next launch, which is the right behavior.

Code shape: three local functions in canvas.lua (no new file — at ~3 functions it's not worth a separate module):

ensure_canvas_dir() — mkdir data/canvases, idempotent, same pattern as content_store_init
save_canvas(elements) — serializer, called on mutation
load_canvas() — deserializer, returns the elements array, called from init

Plus a CANVAS_FILE constant at the top.

Edge cases handled:

First-ever run (file doesn't exist): fresh canvas
Corrupt file (manually edited badly): logged, fresh canvas
Blob missing for a saved element: that element skipped with warning, rest of canvas loads
Multi-mode switching: same pane instance, same self.elements, save state shared across modes (correct — there's one canvas regardless of which mode you view it from)
App crash mid-drag: element keeps its pre-drag position on next launch (since drag doesn't save until release)

What sub-step 3c does NOT address (left for later):

Multiple canvases (one per "document"). Today there's one hardcoded scratch.
Element deletion (Backspace/Delete key). Would need a save trigger too.
Undo/redo. Phase 1 generic concern.
Atomic writes (write to .tmp + rename). For a personal-use app on local disk this is overkill; if we lose one save to a crash, we lose one drop's worth of work.

Estimated ~60–70 lines of Lua, no engine changes, no rebuilding.

If that matches what you'd expect, I'll implement it.

Go ahead.

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

1    --[[
2     canvas — free-flowing element canvas pane.
3   
4     Drops: image files dropped on the canvas are saved to the content
5     store and added as elements at the cursor position, native pixel
6     size. Oversize images overflow the slot intentionally; the stencil
7     clip below hides anything outside the canvas rect, so overflow
8     doesn't bleed into neighboring panes.
9   
10    Element shape (in self.elements):
11      {type='image', blob_id='blob:<hex>.<ext>', image=<image>, x=, y=, w=, h=}
12  
13    blob_id is the persisted reference. `image` is the live texture handle
14    (re-resolved at load time once persistence ships). x/y are top-left
15    in window coordinates (logical pixels). w/h are the rendered size,
16    starting at native image dims and changing as the user resizes.
17  
18    Selection / move / resize:
19      - Click an element body → select + start move.
20      - Drag → moves selected element under cursor (free positioning;
21        stencil handles off-canvas visuals).
22      - Click an empty area → deselect.
23      - Selected element shows a 1px lavender ring + 4 corner squares.
24      - Drag a corner square → aspect-preserving scale, opposite corner
25        pinned. Cursor leads on whichever axis is dragged faster.
26      - Drag an edge band (between corner zones) → aspect-preserving
27        scale, opposite edge pinned, orthogonal axis center-pinned.
28      - Ctrl+click is reserved for the workspace's pane-swap drag and
29        bypasses canvas selection logic entirely.
30  
... [350 more lines]

Now adding persistence. Three local helpers at the top, load_canvas call in init, save_canvas after drop and on drag-end.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Wire up the save/load triggers — load in init, save after drop and on drag-end:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Update the docstring to reflect that persistence is now in place:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

3c ready to test.

What you should see:

Round trip works. Drop a few images, move them around, resize one. Close the app. Reopen → everything's exactly where you left it. Position, size, dedup all preserved.
File on disk. After dropping anything, Anchor2/app/data/canvases/scratch.lua exists. Open it in a text editor and you'll see something like: lua -- Auto-generated by canvas.lua. Safe to delete to reset. return { version = 1, elements = { {type="image", blob_id="blob:005230f61ece6ceb.png", x=147, y=458, w=717, h=477}, }, } Hand-editable. Delete the file to reset to an empty canvas.
Save frequency: writes after every drop, every drag-end, every resize-end. Each save is one ~100-byte write so it's nothing on local disk. NOT writing every frame during the drag — the file stays stable while you're actively manipulating.
Crash recovery:
- Drop image, no further mutations → next launch: image at drop position. ✓
- Drop, move halfway, app crashes before release → next launch: image at drop position (pre-move). ✓ (the drag wasn't yet saved)
- Drop, move, release, app crashes → next launch: image at moved position. ✓
Missing blob handling. If you manually delete a blob file from data/blobs/ while the canvas still references it, on next launch you'll see load_canvas: skipping blob:... (resolve failed) on stderr and that element won't appear. The other elements load normally.

A small thing: the first run after this change will fail to find data/canvases/scratch.lua (doesn't exist yet) → empty canvas. Drop a few images to populate. From there it persists. If you had elements in memory from the previous session before I added persistence, those are lost — there was no save during that session.

If round-tripping works, sub-step 3 is complete and we've finished the original Phase 1 Part 2 scope you described. Worth pausing here to think about what's next (more polish on the canvas? Move to step 7 model layer? Something else entirely?).

Everything seems to work. Let's pause here and go over everything logically. What are the next steps, and then high level overview of the phases.

State of play

We're at a natural pause. The image canvas works end-to-end: drop → save → display → select → move → resize → persist → reload. That checks the "make the app feel like a workspace" goal from sub-step B of the original choice.

But let me be honest about where this sits in the larger plan, because the framing might've drifted.

Phase 1 isn't done. Looking back at plan.md's Phase 1 spec, the milestone is "open the app, create a document, place and arrange text blocks freely, type with formatting, save, close, reopen to same state. Command palette works. Undo works. Hot reload works." We've built:

Phase 1 item	Status
UI system (panes, slots, hit testing, focus, basic widgets)	✅
Canvas + element system (positioned, selectable, moveable, resizable)	✅ (for images)
Persistence	✅ (workspace state + canvas state)
Text layout (word wrap, multi-size, inline formatting)	❌
Text editing (cursor, insertion, arrows, selection, clipboard)	❌
Action system + keybindings (registry, key chord → action)	⚠️ (ad-hoc only — F1/F2/F3 mode keys, no registry)
Command palette	❌
Undo	❌
Hot reload	❌

So we've validated one piece of Phase 1 (the spatial canvas works for images), but text-editing-as-element is the actual primary content type for the "blog post / note" use case, and undo/actions/palette/hot-reload are all still future.

Three honest paths forward

Path A: Polish the canvas a bit more, then pivot to text elements.

Small canvas additions you'd notice missing: Delete key for the selected element, keyboard-driven resize (you mentioned wanting this), z-order (bring forward / send back), maybe SIZEALL cursor on hover-over-body. ~1 short session.

Then text element is the next big Phase 1 chunk. A text element is another element type alongside image — same selection / move / resize plumbing — but its content is wrappable text. Needs:

Text layout (word wrap to element width, line breaking)
Cursor positioning + insertion / deletion / arrow nav
Selection (shift+arrows, click-drag)
Inline formatting (bold/italic/code via Ctrl+B/I/E or similar)
Multi-size headings

This is the biggest single piece of Phase 1 and probably 4-6 sessions. After this, the original milestone is reachable.

Path B: Step 7+8+9 — model layer + embedded views + view clipboard.

The architectural bet. Make canvases, documents, conversations etc. all into models with version counters; make panes views of those models. Two canvas panes can reference the same blob/element and stay in sync. Eventually documents can embed panes inline. View clipboard captures a live pane's state and pastes it as a doc element.

Estimated ~550 lines total across 7+8+9. Doing 7 alone is weak payoff; 7+8 starts to be visible; 7+8+9 is the full bet.

Honest tradeoff with text elements: if we add text elements before step 7, they get retrofitted into the model layer later (text doc = model). If we do step 7 first, text elements are built directly on top of models. The latter avoids rework but defers the "blog post" milestone.

Path C: Cross-app drops via custom Win32 drop target.

You asked for this earlier and we deferred. ~200-300 lines C, half a day. Unblocks "drag image from Chrome/Discord directly into the app" without the workaround of saving-to-disk-first. Doesn't advance any Phase but removes daily friction. Doesn't depend on or block anything.

My read:

A is the most natural if you want to keep momentum on the "blog post tool" goal. Text editing is where the daily-use unlock is.
B is the right move if you're worried about rework when adding text on top of a pre-architecture canvas. The model layer is sneaky important.
C is opportunistic — you can interrupt for it anytime, it doesn't have ordering pressure.

I'd lean A→B: small canvas polish, then text elements built on the existing pattern. The "rework when adding step 7 later" concern is real but text elements are mostly self-contained — the actual integration with models is ~maybe a day of refactor when the time comes. Spending architecture-budget on step 7 now, before you have multiple element types and multiple panes-of-the-same-thing, has the same "premature plumbing" smell I flagged at the start of this session.

But you might disagree. The path I outlined at the start of this session (sub-step B with a canvas pane) was meant to surface exactly this kind of decision, so we're at the choice point now.

High-level phase overview (from `plan.md`)

Phase	Theme	What it unlocks
Track B (parallel)	Engine C additions	HTTP client, dir listing, file watching, async — biggest pending item is HTTP, which gates AI agents and server sync and URL-based drops
1: Foundation ← we are here	Walking skeleton: UI, canvas, text, actions, undo, persistence, hot reload	Open / arrange / type / save / reopen works
2: Daily driver	Vim modal input, named modes, file ops, more element types, AI Oracle	App replaces Notepad for actual writing
3: Filesystem + tagging	No folders, tag-based browser, SQLite metadata, AI Librarian	Explorer no longer needed for work files
4: Code editor	Lua/GLSL syntax, AI Architect (inline diff preview, drift detection)	Basic IDE for app development itself
5: Publishing + server	VPS + Caddy + WASM build, a327ex.com served by engine, doc sync	Triple-use claim validated
6: Writing view	Distraction-free mode, AI Editor with voice-learning, inline suggestions	Prose quality via AI collaboration
7: Reference + knowledge	Web clipper, link graph, AI Cartographer suggests connections	Personal knowledge base
8: Music views	Sheet music / Strudel-like code patterns, AI Composer	Chiptune game music composable in-app
9: Game development views	Game launcher, profiler, balance dashboard, AI Architect for games	Games developed from within the app
10: Background + integration	Cron jobs, inbox for agent-initiated messages, RSS, git ops	App runs overnight tasks; outside world accessible

Dependencies worth holding in mind:

Phases 3 + 4 can run in parallel after Phase 2 (filesystem and code editor don't block each other).
Phases 6–9 can run in any order after Phase 5 (publishing), since they're all view types.
Track B's HTTP client is the biggest multiplier — it gates the AI agents that show up starting Phase 2, the server sync that defines Phase 5, and the URL-drop feature.
The implicit Phase 0 work (step 7+8+9 model layer) isn't called out in the phase list but pierces through the architecture from Phase 1 onward. Doing it earlier means less rework; doing it later means more visible progress first. Real trade-off, no right answer.

The next phase decision (after Phase 1 wraps) is also where the AI agents start landing in earnest. Right now the app is a tool. After Phase 2 it starts being a tool with a persona (Oracle) in it.

This is probably a natural place to end the session if you want to come back fresh with a decision in mind. Let me know how you want to proceed.

Let's do delete, undo, then do B. We'll leave text editing for part 3 of phase 1 in the next session.

Good plan. Concrete order, with testing pauses between each so we don't pile up bugs:

Delete (this turn, ~5 lines)
Undo / redo — global stack, with canvas commands for add/delete/move/resize (~120 lines, new undo.lua module + canvas integration + Ctrl+Z/Y bindings)
Path B, broken into sub-steps:
- 7a: model type basics (id, version, kind). Make canvases into models.
- 7b: pane references model by ID. View/model split for canvas. Two canvas panes can show the same canvas, edits propagate.
- 8: element-host abstraction + embedded_view element type. Pane can be rendered inside a canvas element.
- 9: view clipboard (Cmd+Shift+C/V).

Each Path B sub-step is its own test cycle. Realistically Path B is 3-4 more sessions, not one — there's no shortcut. We'll see how far we get.

Starting with delete now.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Delete is in.

Test: drop a few images, select one, press Delete → element disappears, selection clears, canvas state saves (close/reopen confirms it's gone). Press Delete with nothing selected → no-op.

If that works, I'll start undo next — that's the bigger chunk and worth a clean slate to think through carefully.

Works.

Now undo. Let me start by checking how panes are registered and indexed — I need the pane id for command targeting.

Read (E:\a327ex\Anchor2\app\pane.lua)

1    --[[
2     pane — class + type registry for workspace panes.
3   
4     A pane is a long-lived stateful UI object: file browser, agent panel,
5     code editor, status bar, etc. Each pane has:
6       - id        stable string identity, used in templates / persistence
7       - type      string, looked up in pane_types for behavior
8       - state     per-instance state table (scroll, cursor, fold-state, etc.)
9       - model_id  optional reference to a model (for view/model split)
10  
11    Pane types vs subclassing
12    -------------------------
13    Anchor 2's class() has no inheritance ("if you want a variant, copy and
14    modify"), so we don't subclass pane for each type. Instead:
15  
16      - There is ONE pane class with shared lifecycle plumbing.
17      - Each pane TYPE is a plain table of callbacks registered in
18        pane_types via pane_register_type(name, def).
19      - pane:update / :serialize / :destroy dispatch to the type's
20        callbacks if present.
21  
22    This keeps the stateful object (genuinely OOP) separate from the
23    per-type behavior (procedural data), matching the framework convention.
24  
25    Why panes don't use make_entity
26    -------------------------------
27    Panes manage their own registry (panes, keyed by pane.id) and have an
28    explicit destroy step. They don't need the entity system's collision
29    events, deferred kill queue, or numeric ids. If a specific pane type
30    needs entity integration later, its init callback can call
... [80 more lines]

self.id is stable and panes[id] is the lookup. Now creating undo module + wiring + converting canvas mutations.

Write (E:\a327ex\Anchor2\app\undo.lua)

File created successfully at: E:\a327ex\Anchor2\app\undo.lua (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Add the global Ctrl+Z/Y handler in workspace.lua:

Read (E:\a327ex\Anchor2\app\workspace.lua)

196      workspace_drag.drop_slot      = nil
197     if swapped then workspace_save_state() end
198   end
199 end
200 
201 -- Mode switch input: any registered keybind pressed → switch mode.
202 local function handle_mode_switch_input()
203   for key, mode_name in pairs(mode_keybinds) do
204     if key_is_pressed(key) and workspace_state.active_mode ~= mode_name then
205       workspace_set_mode(mode_name)
206       return  -- one switch per frame is plenty
207     end
208   end
209 end
210 
211 -- Faint 1px ring on the slot under the cursor while Ctrl is held + idle.
212 -- Tells users "this can be Ctrl+dragged" without a tutorial. Disappears the
213 -- moment the drag actually begins (the active drop highlight + ghost take
214 -- over from there).
215 local function paint_drag_affordance(rects)
216   if workspace_drag.state ~= 'idle' then return end
217   if not ctrl_held() then return end
218   local mx, my = mouse_position()
219   local slot = slot_at(rects, mx, my)
220   if not slot then return end
221   local r = rects[slot]
222   local c = theme.lavender_faint
223   layer_rectangle(ui_layer, r.x,             r.y,             r.w, 1,    c())
224   layer_rectangle(ui_layer, r.x,             r.y + r.h - 1,   r.w, 1,    c())
225   layer_rectangle(ui_layer, r.x,             r.y,             1,   r.h,  c())
... [5 more lines]

Edit (E:\a327ex\Anchor2\app\workspace.lua)

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Edit (E:\a327ex\Anchor2\app\workspace.lua)

The file E:\a327ex\Anchor2\app\workspace.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now convert canvas mutations into commands. Adding command constructors at the top of canvas.lua:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now wire commands into the canvas update — replace direct mutations with cmd:apply() + undo_push(cmd), and capture pre-state at drag start:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Convert drag-release to push an undo command (move or resize), and convert drop to use make_add_command:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && for f in undo.lua panes/canvas.lua workspace.lua mai...)

undo.lua OK
panes/canvas.lua    OK
workspace.lua   OK
main.lua    OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Undo + redo ready to test.

What you should see:

Ctrl+Z undoes the last canvas mutation. Ctrl+Y or Ctrl+Shift+Z redoes.
All four canvas operations are undoable:
- Drop an image → Ctrl+Z removes it. Ctrl+Y puts it back.
- Move an image → Ctrl+Z snaps it back to where it was at drag-start. Ctrl+Y returns it to where you dropped it.
- Resize an image → Ctrl+Z restores pre-drag size + position. Ctrl+Y reapplies.
- Delete an image → Ctrl+Z brings it back at its original list index, also re-selects it. Ctrl+Y deletes again.
Long undo chain: drop 3 images, move one, resize one, delete one. Spam Ctrl+Z → each operation undoes in reverse order. Spam Ctrl+Y → reapplies.
Redo invalidation: if you undo a few steps and then perform a new action (drop a new image, move something), the redo stack clears. The actions you'd undone are now gone for good — standard behavior, matches every text editor.
No-op clicks don't pollute the stack: clicking an image without dragging shouldn't push a move command. Same for clicking-and-releasing on a resize handle without moving.
Persistence interaction: each apply/revert saves the canvas to disk, so closing the app right after an undo preserves the undone state.
Cross-mode: Ctrl+Z works in any mode (kit, compose, bare) — handled at workspace level.

Edge cases to maybe verify:

Drop image A. Move A. Ctrl+Z → A snaps back. Ctrl+Z again → A disappears. Ctrl+Z again → nothing (stack empty).
Multi-step undo across operation types (drop → move → resize → delete → Ctrl+Z × 4 should fully reverse).
The 256-deep stack limit isn't tested but shouldn't matter unless you go hog-wild.

If undo behaves correctly, that's the polish work done and we're ready to move into Path B. Let me know.

Seems to work. There's a small bug where if the app goes out of focus, i.e. I click on explorer image to drag it, I have to bring it into focus again to either drop the image or select an existing image, like it takes an additional click. It would be interesting if the action could be taken at the same "event" that makes it back into focus.

That's a Windows window-manager behavior, not a bug in our code. By default, when an SDL window loses focus, the first click on it after returning is consumed by the OS to refocus the window — the app never sees it. SDL has a hint for exactly this case: SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH. Setting it to "1" makes the click pass through to the app as a normal click and refocuses the window in the same event.

Engine fix only — one SDL_SetHint call before SDL_Init.

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

10474                fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
10475               return 1;
10476           }
10477       }
10478   
10479       if (!headless_mode) {
10480           // Set OpenGL attributes (before window creation)
10481           #ifdef __EMSCRIPTEN__
10482           // Request WebGL 2.0 (OpenGL ES 3.0)
10483           SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
10484           SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
10485           SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
10486           #else
10487           // Request OpenGL 3.3 Core Profile
10488           SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
10489           SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
10490           SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
10491           #endif
10492           SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
10493           SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
10494       }
10495   
10496       // Initialize Lua (before window so game can configure via engine_set_* functions)
10497       L = luaL_newstate();
10498       if (!L) {

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

10460                _chdir(game_folder);
10461               #else
10462               chdir(game_folder);
10463               #endif
10464               printf("Game folder: %s\n", game_folder);
10465           }
10466       }
10467   
10468       printf("Loading: main.lua\n");
10469   
10470       // Initialize SDL (headless only needs timer, not video/audio/gamepad)
10471       {
10472           Uint32 sdl_flags = headless_mode ? 0 : (SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_GAMECONTROLLER);
10473           if (SDL_Init(sdl_flags) < 0) {
10474               fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
10475               return 1;
10476           }
10477       }
10478   
10479       if (!headless_mode) {

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/engine && ./build.bat 2>&1 | tail -3 && cp build/anchor.exe...)

Generating Code...
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
Build successful: build/anchor.exe
Engine rebuilt

Test the focus-click-through:

Click somewhere outside the app to defocus it.
Click on a canvas image directly → should select it on the first click (no longer need a second click to actually grab it).
Click on empty canvas while unfocused → app refocuses and deselects in the same event.
Click on a resize handle while unfocused → starts a resize on that click.

A separate scenario worth checking: dragging an image directly from Explorer onto the canvas. The drop event itself was already firing without focus (separate OLE mechanism, unaffected by this hint), but if you wanted to immediately click an existing element on the canvas right after the drop, that click was previously eaten by refocus. Should now work in one click.

If focus-clickthrough behaves the way you want, we're done with this aside and ready to start Path B (sub-step 7a: model type basics). Let me know.

Yep, seems to work. What's next?

Starting Path B — sub-step 7a: model type basics.

Goal: make the canvas's data live in a versioned model rather than directly on the pane. The pane becomes a view of the model. User-visible behavior unchanged — this is pure refactor, the visible payoff comes in 7b (two panes viewing the same canvas).

Plan:

app/model.lua — global models registry, model_new / model_get / model_bump / model_destroy. Each model is {id, kind, version, content}. Generic, type-agnostic.
Canvas data moves into a model. Constant CANVAS_MODEL_ID = 'canvas:scratch'. The existing save/load functions become "save/load the canvas model" — wrap the elements list in model_new(id, 'canvas', {elements=...}). Pane init does self.model = canvas_model_load(); self.elements = self.model.content.elements (alias for readability).
model_bump(self.model) at every mutation point — drop, delete, drag-update each frame, undo/redo. The version counter is what 7b's second view will poll.
Commands target via pane → model — panes[pane_id].model.content.elements. Apply/revert bump and save through the model.

Refactor only. No new UI. After it lands, drop/move/resize/delete/undo/redo all behave identically.

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

66   -- Ensure the canvases directory exists. Same idempotent-mkdir pattern as
67  -- content_store_init: cmd's mkdir creates intermediate dirs and exits 1
68  -- (silenced by 2>nul) when the target is present.
69  local function ensure_canvas_dir()
70    if package.config:sub(1, 1) == '\\' then
71      os.execute('mkdir "data\\canvases" 2>nul')
72    else
73      os.execute('mkdir -p data/canvases')
74    end
75  end
76  
77  -- Serialize the canvas to disk. Only blob_id + position/size are written;
78  -- the live `image` userdata is re-resolved on load. The output is a Lua
79  -- return-table, human-readable and hand-editable in emergencies.
80  local function save_canvas(elements)
81    ensure_canvas_dir()
82    local f, err = io.open(CANVAS_FILE, 'w')
83    if not f then
84      io.stderr:write(('save_canvas: %s\n'):format(tostring(err)))
85      return
86    end
87    f:write('-- Auto-generated by canvas.lua. Safe to delete to reset.\n')
88    f:write('return {\n')
89    f:write('  version = 1,\n')
90    f:write('  elements = {\n')
91    for _, el in ipairs(elements) do
92      if el.type == 'image' then
93        f:write(string.format(
94          '    {type=%q, blob_id=%q, x=%d, y=%d, w=%d, h=%d},\n',
95          el.type, el.blob_id, el.x, el.y, el.w, el.h))
... [5 more lines]

Write (E:\a327ex\Anchor2\app\model.lua)

File created successfully at: E:\a327ex\Anchor2\app\model.lua (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the canvas.lua refactor. First the file/persistence functions:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now update the four undo command constructors to access via panes[pane_id].model.content.elements, bump the model, and save the model:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the pane init and the in-place drag mutations:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now model_bump calls at the in-place drag mutations and the save call at drag-end:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

For the resize branches there are 8 cases (4 corners + 4 edges) — cleaner to bump once after all of them rather than 8 inline calls. Let me look at the resize block to find the right spot:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

315    -- corner zones. Degenerates to no-op when element is smaller than 2×s
316   -- in the relevant dimension.
317   local edge_w = el.w - s*2
318   local edge_h = el.h - s*2
319   if in_rect(mx, my, el.x + s,              el.y,                 edge_w, EDGE_HIT) then return 'edge_top'   end
320   if in_rect(mx, my, el.x + s,              el.y + el.h - EDGE_HIT, edge_w, EDGE_HIT) then return 'edge_bot'   end
321   if in_rect(mx, my, el.x,                  el.y + s,             EDGE_HIT, edge_h) then return 'edge_left'  end
322   if in_rect(mx, my, el.x + el.w - EDGE_HIT, el.y + s,            EDGE_HIT, edge_h) then return 'edge_right' end
323   return nil
324 end
325 
326 pane_register_type('canvas', {
327   init = function(self, opts)
328     -- View of the canvas model. `self.elements` is a direct alias for
329     -- `self.model.content.elements` — convenient shorthand for the
330     -- pane's own update code. Since we only mutate the elements list
331     -- in place (insert/remove), the alias stays valid for the lifetime
332     -- of the model. If the model is ever swapped out (e.g., a future
333     -- "open different canvas"), the alias would need re-binding.
334     self.model        = canvas_model_load()
335     self.elements     = self.model.content.elements
336     self.selected_idx = nil
337     -- Drag state machine. State machine has three states:
338     --   'idle'      → no drag active
339     --   'moving'    → element follows cursor (offset_x/y is grab offset)
340     --   'resizing'  → element resizes from a fixed anchor (mode = which
341     --                 handle, anchor_x/y = pinned point, orig_w/h = the
342     --                 element's dims at click time, used as the resize
343     --                 reference so each fresh click starts fresh)
344     self.drag = {

Bash (grep -n "elseif mode == 'edge_top'" E:/a327ex/Anchor2/app/panes/canvas.lua)

516:            elseif mode == 'edge_top' then

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

512                local dh = math.max(0, my - ay)
513               scale = math.max(dh / oh, min_scale)
514               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
515               el.x, el.y = math.floor(ax - el.w*0.5), ay
516             elseif mode == 'edge_top' then
517               local dh = math.max(0, ay - my)
518               scale = math.max(dh / oh, min_scale)
519               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
520               el.x, el.y = math.floor(ax - el.w*0.5), math.floor(ay - el.h)
521             end
522           end
523         end
524       end
525     end
526

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Let me verify the bump's actually inside the resizing branch by reading the structure:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

478              -- would flip / collapse the element.
479             local min_scale = math.max(MIN_SIZE / ow, MIN_SIZE / oh)
480             local scale
481             if mode == 'corner_br' then
482               local dw, dh = math.max(0, mx - ax), math.max(0, my - ay)
483               scale = math.max(dw / ow, dh / oh, min_scale)
484               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
485               el.x, el.y = ax, ay
486             elseif mode == 'corner_tl' then
487               local dw, dh = math.max(0, ax - mx), math.max(0, ay - my)
488               scale = math.max(dw / ow, dh / oh, min_scale)
489               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
490               el.x, el.y = math.floor(ax - el.w), math.floor(ay - el.h)
491             elseif mode == 'corner_tr' then
492               local dw, dh = math.max(0, mx - ax), math.max(0, ay - my)
493               scale = math.max(dw / ow, dh / oh, min_scale)
494               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
495               el.x, el.y = ax, math.floor(ay - el.h)
496             elseif mode == 'corner_bl' then
497               local dw, dh = math.max(0, ax - mx), math.max(0, my - ay)
498               scale = math.max(dw / ow, dh / oh, min_scale)
499               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
500               el.x, el.y = math.floor(ax - el.w), ay
501             elseif mode == 'edge_right' then
502               local dw = math.max(0, mx - ax)
503               scale = math.max(dw / ow, min_scale)
504               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
505               el.x, el.y = ax, math.floor(ay - el.h*0.5)
506             elseif mode == 'edge_left' then
507               local dw = math.max(0, ax - mx)
... [20 more lines]

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

458            end
459         end
460         self.drag.state = 'idle'
461         self.drag.mode  = nil
462         self.drag.pre   = nil
463         -- Save: drag (move or resize) just ended; persist new position.
464         save_canvas(self.model)
465       else
466         local el = self.selected_idx and self.elements[self.selected_idx]
467         if el then
468           if self.drag.state == 'moving' then
469             el.x = math.floor(mx - self.drag.offset_x)
470             el.y = math.floor(my - self.drag.offset_y)
471             model_bump(self.model)
472           elseif self.drag.state == 'resizing' then
473             local mode = self.drag.mode
474             local ow, oh = self.drag.orig_w, self.drag.orig_h
475             local ax, ay = self.drag.anchor_x, self.drag.anchor_y
476             -- Floor-of-scale: smallest scale that keeps both new dims
477             -- above MIN_SIZE. Without this, dragging past the anchor
478             -- would flip / collapse the element.
479             local min_scale = math.max(MIN_SIZE / ow, MIN_SIZE / oh)
480             local scale
481             if mode == 'corner_br' then
482               local dw, dh = math.max(0, mx - ax), math.max(0, my - ay)

Placement is correct — model_bump(self.model) at line 522 fires every frame inside the resizing branch (after the mode dispatch). Move branch already bumps.

Let me verify everything else compiles and runs:

Bash (cd E:/a327ex/Anchor2/app && for f in model.lua undo.lua panes/canvas.lua main.lu...)

model.lua    OK
undo.lua    OK
panes/canvas.lua    OK
main.lua    OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

7a ready to test.

What you should see: nothing different. This was a pure refactor — the data moved from self.elements directly on the pane into a model (self.model.content.elements), with a version counter that bumps on every mutation. The pane keeps a self.elements alias to the model's element list so most code reads the same.

Sanity tests:

Drop an image, move it, resize it, delete it — all should work identically to before.
Undo/redo still works correctly across all four operation types.
Close + reopen the app → canvas state persists (same disk format).
app/data/canvases/scratch.lua looks exactly like it did before (file format version "1" is unchanged).

What's now in place (invisible but architecturally meaningful):

A global models = {} registry keyed by stable IDs ('canvas:scratch').
The canvas pane's data lives in models['canvas:scratch'], not on the pane itself.
Every canvas mutation calls model_bump(self.model) — version counter increments. For drag operations it bumps every frame.
model_get(id) is the lookup function any future code can use to find a model.

This is the foundation for 7b: a second canvas pane will call canvas_model_load() and get the same model instance. Both panes mutate the same data; both poll the same version. When one drags, the other re-renders.

If nothing's broken, I'll move to 7b — adding a second canvas pane and the version-polling for cross-pane sync.

Everything seems to work, before continuing, let's change redo to CTRL+R.

Edit (E:\a327ex\Anchor2\app\workspace.lua)

The file E:\a327ex\Anchor2\app\workspace.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Done. Ctrl+Z = undo, Ctrl+R = redo. Ctrl+Y and Ctrl+Shift+Z no longer bound.

Verify it works as expected, then I'll start 7b.

Can start it.

Starting sub-step 7b. Let me lay out exactly what changes are needed before applying — this is a bigger refactor than 7a because there are real interaction subtleties when two panes can mutate the same model.

Changes in scope:

Selection by element ref, not index. When pane A has element at index 3 selected and pane B deletes element at index 2, the list shifts and pane A's index-3 selection now points to a different element. Fix: store self.selected_el as a table reference instead of an index. Robust against reordering. Refactor throughout canvas.lua.
Version polling. Each pane stores last_seen_version. At the top of update, if model.version has changed since last seen, re-validate view-local state (clear selection if the selected element is no longer in the model). Stub for canvas because there's no other cached derived state yet — the discipline will earn its keep when text elements arrive (line breaks cached, etc.).
Workspace-level drop routing. Currently both canvas panes would call engine_get_drops() and whichever runs first drains the queue for everyone — drops in pane B's region would be lost if pane A drains them first. Fix: workspace drains drops once per frame, routes to the pane under the cursor via a new pane:on_drop(drop, rect) dispatch. Move canvas's drop logic from update into on_drop.
Defensive mouse-down check in drag. If the canvas pane misses a release event (e.g., mode switched mid-drag), drag state stays 'dragging' forever and any future cursor motion in that pane would snap the element to wherever the cursor is. Fix: if mouse_is_down(1) is false but state is non-idle, bail.
Parameterize model_id. Pane already has self.model_id from opts. Canvas pane reads it (default 'canvas:scratch') and loads the matching model. Two panes with the same model_id share state; two panes with different model_id would view different canvases (which we'll exercise later).
Add canvas_b pane + split template + split mode + F4 keybind. Test artifact — two canvas panes side by side, both bound to 'canvas:scratch'. Drops, moves, resizes, deletes in either pane propagate to the other.

I'll do it as four file edits — pane.lua first (smallest), then canvas.lua (biggest), then workspace.lua, then main.lua.

Edit (E:\a327ex\Anchor2\app\pane.lua)

The file E:\a327ex\Anchor2\app\pane.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the canvas.lua refactor. Starting with the path/load/save parameterization:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now refactor the four undo commands to use selected_el instead of selected_idx:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Refactor hit_test to return the element, and update init (model_id from opts, selected_el, last_seen_version):

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the body of update — version polling + replace selected_idx with selected_el everywhere. Let me read the current state of the update body:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

370      -- will earn the polling pattern's value.
371     self.last_seen_version = self.model.version
372 
373     -- Drag state machine. Three states:
374     --   'idle'      → no drag active
375     --   'moving'    → element follows cursor (offset_x/y is grab offset)
376     --   'resizing'  → element resizes from a fixed anchor (mode = which
377     --                 handle, anchor_x/y = pinned point, orig_w/h = the
378     --                 element's dims at click time, used as the resize
379     --                 reference so each fresh click starts fresh)
380     self.drag = {
381       state    = 'idle',
382       mode     = nil,
383       offset_x = 0,
384       offset_y = 0,
385       anchor_x = 0,
386       anchor_y = 0,
387       orig_w   = 0,
388       orig_h   = 0,
389     }
390   end,
391 
392   update = function(self, dt, input, rect)
393     local mx, my = mouse_position()
394     local cursor_in_rect = mx >= rect.x and mx < rect.x + rect.w
395                        and my >= rect.y and my < rect.y + rect.h
396     local ctrl_held = key_is_down('lctrl') or key_is_down('rctrl')
397 
398     -- Delete: remove the selected element. Bound to the dedicated Delete
399     -- key (not Backspace — Backspace will be the text-element delete
... [100 more lines]

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

516          self.drag.state = 'idle'
517         self.drag.mode  = nil
518         self.drag.pre   = nil
519         -- Save: drag (move or resize) just ended; persist new position.
520         save_canvas(self.model)
521       else
522         local el = self.selected_idx and self.elements[self.selected_idx]
523         if el then
524           if self.drag.state == 'moving' then
525             el.x = math.floor(mx - self.drag.offset_x)
526             el.y = math.floor(my - self.drag.offset_y)
527             model_bump(self.model)
528           elseif self.drag.state == 'resizing' then
529             local mode = self.drag.mode
530             local ow, oh = self.drag.orig_w, self.drag.orig_h
531             local ax, ay = self.drag.anchor_x, self.drag.anchor_y
532             -- Floor-of-scale: smallest scale that keeps both new dims
533             -- above MIN_SIZE. Without this, dragging past the anchor
534             -- would flip / collapse the element.
535             local min_scale = math.max(MIN_SIZE / ow, MIN_SIZE / oh)
536             local scale
537             if mode == 'corner_br' then
538               local dw, dh = math.max(0, mx - ax), math.max(0, my - ay)
539               scale = math.max(dw / ow, dh / oh, min_scale)
540               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)
541               el.x, el.y = ax, ay
542             elseif mode == 'corner_tl' then
543               local dw, dh = math.max(0, ax - mx), math.max(0, ay - my)
544               scale = math.max(dw / ow, dh / oh, min_scale)
545               el.w, el.h = math.floor(ow * scale), math.floor(oh * scale)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Grep (mouse_is_down|"mouse_is_down")

8008:static int l_mouse_is_down(lua_State* L) {
9329:    lua_register(L, "mouse_is_down", l_mouse_is_down);

Good. Now find the rest of the canvas update — selection chrome and the drop loop to extract into on_drop:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

585          end
586       end
587     end
588 
589     -- Process drops. Only consume drops when the cursor is inside the
590     -- canvas rect — drops elsewhere on the window get logged and ignored.
591 
592     for _, drop in ipairs(engine_get_drops()) do
593       if not cursor_in_rect then
594         print(string.format('[canvas] drop outside canvas rect (%s): %s',
595           drop.kind, drop.value))
596       elseif drop.kind == 'file' then
597         local id, err = content_store_put(drop.value)
598         if id then
599           local img = content_store_resolve(id)
600           if img then
601             -- Always native size on drop. Stencil clip below hides any
602             -- portion that overflows the canvas rect.
603             local w, h = img.width, img.height
604             local el = {
605               type    = 'image',
606               blob_id = id,
607               image   = img,
608               x       = math.floor(mx - w*0.5),
609               y       = math.floor(my - h*0.5),
610               w       = w,
611               h       = h,
612             }
613             -- Push as an undo command so Ctrl+Z can revert the drop.
614             -- cmd:apply() does the insert + save_canvas; we don't repeat.
... [60 more lines]

Removing the drop loop from update (workspace will own routing now) and updating selection chrome to use selected_el:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Update the selection chrome to use selected_el:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now add the on_drop callback at the end of the pane type definition:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

650            layer_rectangle(ui_layer, mx_, el.y,            s, s, c())
651           layer_rectangle(ui_layer, mx_, el.y + el.h - s, s, s, c())
652         end
653         -- Left + right midpoint squares.
654         if el.h >= s*3 then
655           local my_ = math.floor(el.y + el.h*0.5 - s*0.5)
656           layer_rectangle(ui_layer, el.x,            my_, s, s, c())
657           layer_rectangle(ui_layer, el.x + el.w - s, my_, s, s, c())
658         end
659       end
660     end
661 
662     -- Disable stencil so other panes draw normally for the rest of the
663     -- frame. (Without this, every subsequent draw on this layer would
664     -- still be stencil-masked to our canvas rect.)
665     layer_stencil_off(ui_layer)
666   end,
667 })
668

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now workspace.lua gets the drop routing — drain once, route to pane under cursor:

Edit (E:\a327ex\Anchor2\app\workspace.lua)

The file E:\a327ex\Anchor2\app\workspace.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\workspace.lua)

The file E:\a327ex\Anchor2\app\workspace.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Last piece — main.lua: add the second canvas pane, split template/mode, and F4 binding:

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && for f in model.lua undo.lua pane.lua workspace.lua m...)

model.lua    OK
undo.lua    OK
pane.lua    OK
workspace.lua   OK
main.lua    OK
panes/canvas.lua    OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

7b is in. Run it and try the split-mode demo.

What to test:

Sanity in single-pane modes (F1 kit, F2 compose, F3 bare). Everything should behave identically to before — drops, drags, resizes, deletes, undo, redo. This is the "refactor didn't break anything" baseline.
F4 to enter split mode. You'll see two canvas regions side by side: a 600-px-wide one on the left (canvas_b), and the rest filling the body. Both share the same canvas data.
Drop in either pane. Drop an image at mouse x=300 (left pane). Element gets added at that window position. If the image is wide enough, you'll see it split across the boundary — the part at x<600 visible in the left pane, the part at x≥600 visible in the right pane. Visual confirmation that they share data.
Drag in either pane. Click on an image in the left pane, drag it. The image follows the cursor in BOTH panes (each one clipping to its own rect). Drag it from left into right and you'll see it cross the slot boundary continuously.
Resize in either pane. Same — resize a corner, both panes update live.
Selection is per-pane. Click element X in the left pane → only the left pane shows the lavender ring. Right pane shows the element with no chrome. Click element Y in the right pane → right pane gets a ring on Y, left pane still rings X (or, if X and Y are the same element, both rings draw on it).
Cross-pane delete. Select X in left pane, then Delete. X disappears from both panes. The right pane's selection (if it had selected the same element) is auto-cleared by version polling.
Undo / redo across panes. Drop in left, drag in right, delete in left, then Ctrl+Z three times. The history reverses correctly regardless of which pane each action originated from — undo stack is global, commands target their originating pane.
Switch back to F1/F2/F3. Returns to the single-canvas modes. canvas_b is unloaded from the view but still has its in-memory state; switching back to F4 brings it back instantly with the same selection state.

Architectural verification (the actual point of 7b):

Two panes view one model ('canvas:scratch').
They share model.content.elements via direct table reference.
Mutations from either propagate to both because both observe the same table.
Version polling clears stale selections when the other pane's edits invalidate them.
Drops route via the workspace to the cursor-target pane (no queue racing).
Undo commands target the originating pane but the model is shared, so the effect is visible in both.

One existing-state caveat: your saved state probably doesn't have a split entry in .workspace_state.lua. The first time you press F4, the workspace will create one from the registered mode defaults — both panes assigned correctly. Subsequent F4 just reactivates.

If split mode works the way I described, sub-step 7b is done and we're ready for step 8 (embedded view as a canvas element type — a pane inside a document).

Doesn't seem to be working. I press F4 and add an image to left pane and it just gets added normally, although there's a bug where I can't visually see the selection markers around it. Either way, I move it anywhere on the screen and it doesn't seem to be affected by the panes at all, I can just move it freely. Perhaps there are two images but they're in the exact same position and both being manipulated at the same time? That would make sense.

Diagnosis: stencil buffer isn't cleared between pane mask calls. When pane B sets up its stencil mask, pane A's 1s in its rect are still there — so pane B's test passes in the union of both rects. Pane B's element draws (step 10 in render order) render across the boundary, overwriting pane A's already-drawn chrome.

So your "free movement" symptom and "missing selection markers" are the same bug: pane B's image draws stomp pane A's region.

Fix is one line in the engine — glClear(GL_STENCIL_BUFFER_BIT) at the start of each COMMAND_STENCIL_MASK so each mask defines a fresh region rather than accumulating with the previous.

Edit (E:\a327ex\Anchor2\engine\src\anchor.c)

The file E:\a327ex\Anchor2\engine\src\anchor.c has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/engine && ./build.bat 2>&1 | tail -3 && cp build/anchor.exe...)

Generating Code...
LINK : warning LNK4098: defaultlib 'MSVCRT' conflicts with use of other libs; use /NODEFAULTLIB:library
Build successful: build/anchor.exe
Engine rebuilt

Try F4 again.

What you should see now:

Drop image at x=300 (left pane). It renders fully visible in the left pane (clipped to x < 600). Visible portion in the right pane: nothing yet (the image is at x=300 to x=300+w; if w > 300 it crosses the boundary and the right pane shows the right portion starting at x=600).
Drag the image rightward → as the left edge crosses x=600, the left pane stops showing the image, and the right pane starts showing it. As it travels across, you see the image transition cleanly between panes.
Select an image — selection chrome (lavender ring + handles) should now be visible. The right pane's draws no longer overwrite the left pane's chrome.

One known minor issue I'm not fixing here: cursor setting races between the two panes (each sets it every frame). Most of the time pane B's arrow overrides pane A's resize cursor. Will manifest as the cursor not switching to the resize arrow when hovering a handle in split mode. Fixable later by centralizing cursor through the workspace; not urgent.

Confirm clipping works, then we move to step 8 (embedded views).

The selection bug is not there anymore, but I only see the image normally again, I can just drag it anywhere. I don't understand what I am supposed to test if I can just drag the image normally.

Wait, let me check — your saying "I can just drag it anywhere" makes me want to confirm whether the stencil is actually clipping anymore. Let me check the layer's FBO has stencil attached, which is required for glClear(GL_STENCIL_BUFFER_BIT) to actually do anything:

Grep (GL_STENCIL|stencil.*attach|GL_DEPTH24_STENCIL8|GL_STENCIL_INDEX)

1794:    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
4649:                glEnable(GL_STENCIL_TEST);
4651:                glClear(GL_STENCIL_BUFFER_BIT);
4677:                glDisable(GL_STENCIL_TEST);
5670:    glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
5673:    glDisable(GL_STENCIL_TEST);
5680:    glDisable(GL_STENCIL_TEST);

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

5660     if (headless_mode) return 0;
5661        Layer* layer = (Layer*)lua_touserdata(L, 1);
5662    
5663        // Bind layer's FBO
5664        glBindFramebuffer(GL_FRAMEBUFFER, layer->fbo);
5665        glViewport(0, 0, layer->width, layer->height);
5666    
5667        // Clear color and stencil buffers
5668        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
5669        glClearStencil(0);
5670        glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
5671    
5672        // Ensure stencil starts disabled
5673        glDisable(GL_STENCIL_TEST);
5674        glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
5675    
5676        // Process all queued commands
5677        layer_render(layer);
5678    
5679        // Ensure stencil is disabled after rendering (in case commands left it enabled)
5680        glDisable(GL_STENCIL_TEST);
5681        glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
5682    
5683        // Clear command queue for next frame
5684        layer->command_count = 0;
5685    
5686        return 0;
5687    }
5688    
5689    // Draw source layer's texture to destination layer's FBO

Stencil's properly attached and the engine already clears stencil at the start of each layer_render — my fix should be working. Let me double-check the binary is the freshly built one:

Bash (ls -la E:/a327ex/Anchor2/engine/build/anchor.exe E:/a327ex/Anchor2/app/anchor.ex...)

-rwxr-xr-x 1 adn 197121 4181504 May 10 23:07 E:/a327ex/Anchor2/app/anchor.exe
-rwxr-xr-x 1 adn 197121 4181504 May 10 23:07 E:/a327ex/Anchor2/engine/build/anchor.exe

Grep (^function color(|^color = function)

No matches found

Bash (head -40 E:/a327ex/Anchor2/app/anchor/color.lua)

--[[
  color — mutable RGBA color with HSL conversion helpers.

  Simpler than v1's color class. A color is a plain table {r, g, b, a} with
  a __call metamethod that returns the packed rgba integer used by drawing
  functions. No auto-sync between RGB and HSL — HSL is a *conversion*, not a
  storage format. If you want to modify hue, convert to HSL, modify, convert
  back.

  Usage:
    red = color_new(255, 0, 0)
    red.a = 128              -- set alpha
    layer_circle(game_layer, x, y, r, red())  -- __call returns packed rgba integer

    -- HSL manipulation:
    h, s, l = color_to_hsl(red)
    h = (h + 120) % 360      -- shift hue
    shifted = color_from_hsl(h, s, l, red.a)

    -- Common operations:
    copy = color_clone(red)
    mixed = color_mix(red, blue, 0.5)
    dark = color_darken(red, 0.5)      -- multiply RGB by 0.5
    light = color_lighten(red, 1.5)    -- multiply RGB by 1.5 (clamped)
    inverted = color_invert(red)

  Design notes:
    - Colors are plain tables. Modify fields directly: c.r = 100.
    - Procedural functions (color_mix, color_clone, etc.) return NEW colors,
      not mutating the input. If you want to mutate, do `c.r = ...` directly.
... [10 more lines]

The fix is working — the issue is that you can't tell there are two panes because they have the same background color, so visually the image looks continuous as it moves across. The model sharing IS real, just invisible.

Two things will make the test clear:

Code change: make canvas_b's background slightly different so the boundary is visible.
Better test instructions: drop a wide image AT the boundary and look for it splitting + per-pane selection chrome.

Quick code change — make canvas pane accept an optional bg color override:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated. All occurrences were successfully replaced. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Now in split mode, the left pane (canvas_b) has a slightly darker bg (bg_inset) than the main (bg_base). You'll see a clear color boundary at x=600.

Test that proves model sharing works:

F4 to enter split mode. You'll see a subtle but visible color difference between the two halves. That's the slot boundary.
Drop a wide image at the boundary. Move your cursor to roughly x=550 (just inside the left pane's right edge) and drop. The image is wide (e.g., 717×477), so its bounding box at drop time extends from x=550-W/2 to x=550+W/2 — spanning both panes.
Look at the image: it's drawn in two clipped halves, but they're abutted along the boundary line at x=600. To your eye it's one image, but the left half is rendered by canvas_b (against the darker bg) and the right half is rendered by main_canvas (against the lighter bg). Look carefully along x=600 — you might see a tiny visual seam if the image has texture across that line.
Click the image in the LEFT pane (cursor x < 600 on the image). Lavender ring + handles appear. Importantly, look at the right pane: the image is visible there too, but NO ring. That's per-pane selection — both panes view the same element, but only one has a selection state.
Click the image in the RIGHT pane (cursor x > 600 on the image). The ring moves to the right pane. The left pane's selection clears (because the click happened over x>600 and the left pane saw cursor_in_rect=false → didn't fire its own selection logic, but ALSO didn't deselect; actually, the left pane's selection should stay — that's the point of per-pane selection). Hmm — actually let me re-think.

Actually for step 5: the LEFT pane's selection persists (clicking in the right pane doesn't affect the left pane's selection state). So you'd see rings in BOTH panes. That's also a valid test outcome: each pane independently tracks selection.

Drag the image in either pane. Both halves move together. The bg color underneath them changes as they cross the boundary.
Resize from a corner in the left pane. Both halves update in real-time.
Delete with Delete key. Image gone from both panes.
Ctrl+Z. Image returns to both panes, selection restored on the pane that initiated the delete.

The key thing you're proving: there's ONE element in the model, and BOTH panes are rendering it independently. The architectural primitive (shared model, separate views) is what makes step 8 (embedded views inside documents) and step 9 (view clipboard) possible.

Try it again, this time with the bg distinction guiding your eye to the boundary.

I understand now. But it would be an easier test if both panes were separated by something irrelevant in the middle. Also, actually, shouldn't we want both panes to be exactly the same in terms of view? So if we have pane A with only the left portion of an image being drawn, and we have a copy of pane A displaying elsewhere, shouldn't we see that same left portion of the image instead of its right portion? I don't understand why we'd see the full image. The idea behind this is that I can post a game inside a blog post. The game is its own frame, and we a copy of this frame into a blog post. It should be exactly the same in the blog post as it is on its own. Am I understand something incorrectly?

You're 100% right, and I was wrong about how to model this. Let me explain what's happening currently and what we should do.

The bug in the current design

Element coordinates are stored as window-absolute positions (el.x = 500 means "pixel 500 from the left edge of the window"). Each pane then just clips its rect with stencil. Two panes viewing the same model show whatever portion of those window-absolute elements happens to overlap each pane's rect — which is different per pane.

That's wrong for your use case. If pane A shows a game-frame, then a "copy of pane A" placed inside a blog post should show the same thing as pane A — same element positions, same clipping, same everything. Not a different slice of the same window-space.

The right design

Element coordinates should be canvas-local — el.x = 250 means "pixel 250 from the canvas's origin". Each pane has its own (rect.x, rect.y) origin, and renders elements at window(rect.x + el.x, rect.y + el.y). Input is translated the other way: canvas(mx - rect.x, my - rect.y).

Consequences:

A 600-pixel-wide element at canvas (0, 0) placed in a 600-pixel-wide pane fits exactly. Placed in a smaller pane, it overflows and gets stencil-clipped.
Two panes of the same size show identical content (same canvas-local positions, same clipping). That's the embed property.
Two panes of different sizes show different amounts. The smaller pane clips more, the larger pane shows more — but it's the same canvas data, just framed differently.
Same canvas viewed across modes (e.g., kit body vs bare body) renders consistently — the canvas content sits at canvas coords, the pane window moves around it.

Your "embed a game inside a blog post" use case is exactly this: the game's pane has a defined size; the blog post embeds a pane of the same size pointing at the same game model; identical content.

What needs to change

Canvas pane refactor (canvas.lua). Everywhere it computes/uses element positions in window coords, switch to canvas-local. This is a focused but pervasive edit:
- cx, cy = mx - rect.x, my - rect.y at top of update.
- All hit testing, drop position, drag offset, resize anchor — use cx, cy and el.x, el.y as canvas-local.
- Rendering translates by rect origin: layer_push at (rect.x + el.x + el.w*0.5, rect.y + el.y + el.h*0.5, ...).
- Selection chrome rendered at rect.x + el.x, rect.y + el.y.
Split mode template (main.lua) — to make the embed-equivalence visible, two equally sized canvas slots separated by something irrelevant in the middle. Per your suggestion: lua workspace_register_template('split', { {name='status_top', edge='top', size=24}, {name='status_bot', edge='bottom', size=22}, {name='canvas_left', edge='left', size=600}, {name='canvas_right', edge='right', size=600}, {name='middle', fill=true}, -- some placeholder panel }) Both canvas slots are 600×~1034. They show the same canvas-local content identically. The middle panel is just filler (use panel_a as a placeholder) so you can visually see the gap.
Reset existing canvas data. Your saved app/data/canvases/scratch.lua has elements with window-absolute coordinates from before this change. After the refactor those numbers get interpreted as canvas-local, so the elements will shift visually. Easiest: rm app/data/canvases/scratch.lua before re-testing. (Could write a migration but the data is throwaway.)

Want me to do all three? It's a focused refactor — maybe 30-40 lines changed in canvas.lua, 5 in main.lua. After it lands, the split-mode test becomes obvious: drop something in canvas_left, see exactly the same thing in canvas_right. Edit either, both update.

Yes.

Doing the refactor.

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

395    end,
396 
397   update = function(self, dt, input, rect)
398     -- Version polling. If the model has changed since we last looked
399     -- (another pane mutated it, or our own last action), re-validate
400     -- view-local state that depends on the model. For canvas: clear
401     -- selection if the selected element is no longer in the elements
402     -- list; abort an in-flight drag if its target disappeared.
403     if self.last_seen_version ~= self.model.version then
404       if self.selected_el and not index_of(self.model.content.elements, self.selected_el) then
405         self.selected_el = nil
406         if self.drag.state ~= 'idle' then
407           self.drag.state = 'idle'
408           self.drag.mode  = nil
409           self.drag.pre   = nil
410         end
411       end
412       self.last_seen_version = self.model.version
413     end
414 
415     local mx, my = mouse_position()
416     local cursor_in_rect = mx >= rect.x and mx < rect.x + rect.w
417                        and my >= rect.y and my < rect.y + rect.h
418     local ctrl_held = key_is_down('lctrl') or key_is_down('rctrl')
419 
420     -- Delete: remove the selected element. Bound to the dedicated Delete
421     -- key (not Backspace — Backspace will be the text-element delete
422     -- when that lands in Phase 1 Part 3).
423     if self.selected_el and key_is_pressed('delete') then
424       local el  = self.selected_el
... [90 more lines]

Replacing the input section — adding cx/cy and switching all element-interaction code to canvas-local:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Drag update — switch all mx/my to cx/cy:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

528          end
529         self.drag.state = 'idle'
530         self.drag.mode  = nil
531         self.drag.pre   = nil
532         -- Save: drag (move or resize) just ended; persist new position.
533         save_canvas(self.model)
534       elseif not mouse_is_down(1) then
535         -- Stale drag — we missed the release event somehow. Bail.
536         self.drag.state = 'idle'
537         self.drag.mode  = nil
538         self.drag.pre   = nil
539       else
540         local el = self.selected_el
541         if el then
542           if self.drag.state == 'moving' then
543             el.x = math.floor(mx - self.drag.offset_x)
544             el.y = math.floor(my - self.drag.offset_y)
545             model_bump(self.model)
546           elseif self.drag.state == 'resizing' then
547             local mode = self.drag.mode
548             local ow, oh = self.drag.orig_w, self.drag.orig_h
549             local ax, ay = self.drag.anchor_x, self.drag.anchor_y
550             -- Floor-of-scale: smallest scale that keeps both new dims
551             -- above MIN_SIZE. Without this, dragging past the anchor
552             -- would flip / collapse the element.
553             local min_scale = math.max(MIN_SIZE / ow, MIN_SIZE / oh)
554             local scale
555             if mode == 'corner_br' then
556               local dw, dh = math.max(0, mx - ax), math.max(0, my - ay)
557               scale = math.max(dw / ow, dh / oh, min_scale)
... [50 more lines]

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now wrap the rendering (elements + selection chrome) in a layer_push(rect.x, rect.y, ...) so the rest of the code stays in canvas-local coords:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Pop the canvas-local transform right before stencil_off:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now on_drop — compute canvas-local cursor and use for new element position:

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Now the split mode template in main.lua — two equal-width canvas slots with a panel filling the middle:

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Edit (E:\a327ex\Anchor2\app\main.lua)

The file E:\a327ex\Anchor2\app\main.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Sanity-check the build:

Bash (cd E:/a327ex/Anchor2/app && for f in panes/canvas.lua main.lua; do /e/a327ex/Anc...)

panes/canvas.lua OK
main.lua    OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Refactor is done. Two things:

Reset your saved canvas before testing — the coordinate semantics changed, so existing positions will appear shifted (e.g., an element saved at window-pos (147, 458) will now be interpreted as canvas-local, and rendered at rect.x + 147, rect.y + 458 — shifted by however far the pane's top-left is from the window origin).

rm E:/a327ex/Anchor2/app/data/canvases/scratch.lua

Test in split mode (F4). You'll see:
A 600×~1034 canvas slot on the left (canvas_left → canvas_b pane, dim bg).
A filler panel in the middle (whatever's left, ~720 wide → panel_a placeholder).
A 600×~1034 canvas slot on the right (canvas_right → main_canvas pane, normal bg).

The embedded-view property: drop an image in the left canvas, anywhere inside its rect. You'll see exactly the same content mirror in the right canvas — same canvas-local position, same clipping, same everything. Drag it, resize it, delete it in either canvas; both update simultaneously. The middle panel sits between as visual proof that they're physically separate frames showing identical content.

Per-pane selection still works: clicking on the image in the left canvas selects in the left only (ring + handles there). Clicking on the image in the right canvas selects in the right (its own ring + handles). The two selections are independent because selection is view-local state, not model state.

This is the architectural primitive for step 8 (embedded views in documents) and step 9 (view clipboard). If two panes can show identical content, then the same pane class can also render inside a canvas element of a document — same code path, different host (slot vs canvas-element).

Try it and let me know if both canvases mirror each other exactly.

[Pasted image/png]

The way the image stencils is going over the neighbor pane's border and a bit of its inside actually.

Looking at this — the stencil should be clipping at the boundary. Let me check that the layer FBO actually has stencil attached and that I'm reading the engine correctly:

Grep (glRenderbufferStorage.STENCIL|glFramebufferRenderbuffer.STENCIL|GL_DEPTH_STENCIL_ATTACHMENT|GL_STENCIL_ATTACHMENT)

1792-    glGenRenderbuffers(1, &layer->stencil_rbo);
1793-    glBindRenderbuffer(GL_RENDERBUFFER, layer->stencil_rbo);
1794:    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
1795:    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, layer->stencil_rbo);
1796-    mem_gl_rbo_count++;
1797-
1798-    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {

Wait, let me look at how slot rects are actually computed. The split layout order might be producing wrong rects:

Read (E:\a327ex\Anchor2\app\rect.lua)

1    --[[
2     rect — RectCut layout primitive for app UI.
3   
4     A rect is a plain table {x, y, w, h}. Three families of operations:
5   
6       cut_*(r, n) — mutates r (eats n pixels from one side), returns the eaten slice.
7       get_*(r, n) — pure: returns a slice of r without mutating.
8       add_*(r, n) — pure: returns a new rect adjacent to r (extends outward).
9   
10    Plus utilities: contract / expand (inset / outset), center (place a w×h
11    rect centered inside another), split_h / split_v (divide into n equal parts).
12  
13    Origin: cut/get/add are the Halt RectCut pattern. Cuts are destructive on
14    the parent so successive cuts walk the rect. Canonical idiom:
15      local topbar = rect_cut_top(r, 24)   -- r is now the body below the topbar
16      local botbar = rect_cut_bot(r, 22)   -- r is now the body between bars
17  ]]
18  
19  function rect_new(x, y, w, h)
20    return {x = x, y = y, w = w, h = h}
21  end
22  
23  -- cut_*: mutate r (eat n from one side), return the eaten slice.
24  function rect_cut_left(r, n)
25    local s = {x = r.x, y = r.y, w = n, h = r.h}
26    r.x = r.x + n
27    r.w = r.w - n
28    return s
29  end
30  function rect_cut_right(r, n)
... [69 more lines]

Let me look at the lua framework wrappers for layer_stencil_*. There was that "engine name conflict" footgun before (layer_draw_texture not having a wrapper) — maybe stencil functions have the same issue:

Grep (layer_stencil|stencil_mask|stencil_test|stencil_off)

76:  stencil_mask = layer_stencil_mask,
77:  stencil_test = layer_stencil_test,
78:  stencil_test_inverse = layer_stencil_test_inverse,
79:  stencil_off = layer_stencil_off,
260:function layer_stencil_mask(lyr)
261:  eng.stencil_mask(lyr_handle(lyr))
264:function layer_stencil_test(lyr)
265:  eng.stencil_test(lyr_handle(lyr))
268:function layer_stencil_test_inverse(lyr)
269:  eng.stencil_test_inverse(lyr_handle(lyr))
272:function layer_stencil_off(lyr)
273:  eng.stencil_off(lyr_handle(lyr))

Read (E:\a327ex\Anchor2\app\main.lua)

200  
201 -- Pane instances. status_top / status_bot are workspace-global panes that
202 -- live in every mode. side_a / side_b host panel placeholders so drag-to-
203 -- swap has multiple swappable targets. main_canvas is the free-flowing
204 -- canvas (drop image files onto it; sub-step 2). panel_b is unused in
205 -- compose and bare modes — it stays in memory and reappears when kit is
206 -- reactivated.
207 pane({id='global_status_top', type='status_top'})
208 pane({id='global_status_bot', type='status_bot'})
209 pane({id='panel_a',           type='panel', title='Panel A'})
210 pane({id='panel_b',           type='panel', title='Panel B'})
211 pane({id='main_canvas',       type='canvas', model_id='canvas:scratch'})
212 pane({id='canvas_b',          type='canvas', model_id='canvas:scratch', bg=theme.bg_inset})
213 
214 -- Make sure the blob storage directory exists on disk.
215 content_store_init()
216 
217 -- Mode-switch keybinds.
218 workspace_bind_mode_key('f1', 'kit')
219 workspace_bind_mode_key('f2', 'compose')
220 workspace_bind_mode_key('f3', 'bare')
221 workspace_bind_mode_key('f4', 'split')
222 
223 -- Restore last session's layout if present; otherwise fall back to kit.
224 if not workspace_load_state() then

Grep (glStencilMask)

No matches found

Let me check whether the smooth UI layer actually has stencil. Maybe smooth mode skips the stencil renderbuffer:

Grep (l_layer_create|static int l_layer_create|FILTER_SMOOTH.*stencil|stencil_rbo)

457:    GLuint stencil_rbo;     // Stencil renderbuffer for masking
1792:    glGenRenderbuffers(1, &layer->stencil_rbo);
1793:    glBindRenderbuffer(GL_RENDERBUFFER, layer->stencil_rbo);
1795:    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, layer->stencil_rbo);
1800:        glDeleteRenderbuffers(1, &layer->stencil_rbo);
1823:    if (layer->stencil_rbo) {
1824:        glDeleteRenderbuffers(1, &layer->stencil_rbo);
4743:static int l_layer_create(lua_State* L) {
9147:    lua_register(L, "layer_create", l_layer_create);

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

1760     // Initialize command queue (fixed size, never grows)
1761        layer->commands = (DrawCommand*)malloc(MAX_COMMAND_CAPACITY * sizeof(DrawCommand));
1762        if (!layer->commands) {
1763            free(layer);
1764            return NULL;
1765        }
1766        layer->command_count = 0;
1767        layer->command_capacity = MAX_COMMAND_CAPACITY;
1768        layer->current_blend = BLEND_ALPHA;
1769    
1770        GLint tex_filter = (layer_filter == FILTER_SMOOTH) ? GL_LINEAR : GL_NEAREST;
1771    
1772        // Create FBO
1773        glGenFramebuffers(1, &layer->fbo);
1774        glBindFramebuffer(GL_FRAMEBUFFER, layer->fbo);
1775        mem_gl_fbo_count++;
1776    
1777        // Create color texture
1778        glGenTextures(1, &layer->color_texture);
1779        glBindTexture(GL_TEXTURE_2D, layer->color_texture);
1780        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
1781        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, tex_filter);
1782        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, tex_filter);
1783        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1784        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1785        mem_gl_texture_count++;
1786        mem_gl_texture_bytes += (size_t)width * (size_t)height * 4;
1787    
1788        // Attach color texture to FBO
1789        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, layer->color_texture, 0);
... [30 more lines]

Grep (glScissor|GL_SCISSOR_TEST|glEnable.*SCISSOR)

No matches found

Let me read the latest canvas update to double-check the order of operations:

Read (E:\a327ex\Anchor2\app\panes\canvas.lua)

607      -- Bg fill (visible). Drawn before the stencil mask so the bg color
608     -- actually paints; stencil_mask disables color writes.
609     layer_rectangle(ui_layer, rect.x, rect.y, rect.w, rect.h, self.bg())
610 
611     -- Stencil clip: write the canvas rect's shape into the stencil buffer,
612     -- then enable stencil testing so subsequent draws only land where the
613     -- stencil is set. Anything outside the canvas rect (oversize images
614     -- bleeding past the slot) is clipped out — stays out of side panels.
615     layer_stencil_mask(ui_layer)
616     layer_rectangle(ui_layer, rect.x, rect.y, rect.w, rect.h, self.bg())
617     layer_stencil_test(ui_layer)
618 
619     -- Push a translation so element + chrome draws below can use
620     -- canvas-local coords directly (matches how el.x/el.y are stored
621     -- and how input cx/cy is computed). At pop time we're back in
622     -- window coords. The stencil set up above is in window coords and
623     -- is unaffected by this push.
624     layer_push(ui_layer, rect.x, rect.y, 0, 1, 1)
625 
626     -- Elements. layer_image draws centered at (x, y) at native size, so we
627     -- push a transform that translates to the element center and scales by
628     -- (target_w/native_w, target_h/native_h) — the centered draw at (0, 0)
629     -- lands exactly with top-left at (el.x, el.y) at the desired w/h.
630     --
631     -- Important: don't call `layer_draw_texture` directly — that's the raw
632     -- engine binding that expects a Layer* lightuserdata as arg 1. Use
633     -- `layer_image` (or `layer_texture`), which is the framework wrapper
634     -- that accepts the layer state table from layer_new.
635     for _, el in ipairs(self.elements) do
636       if el.type == 'image' then
... [55 more lines]

I wonder if this is anti-aliasing on the stencil mask itself. The smooth layer uses SDF rendering — edges have a 1-2 pixel transition zone. If the stencil mask rect's right edge has AA bleeding past x=600, the stencil would be 1 (or partially set) just past 600 too, letting image draws bleed slightly across the boundary.

Let me check how the engine's rectangle draws relate to stencil:

Grep (process_rectangle|case COMMAND_RECTANGLE)

3875:static void process_rectangle(const DrawCommand* cmd) {
3926:static void process_rectangle_gradient_h(const DrawCommand* cmd) {
3977:static void process_rectangle_gradient_v(const DrawCommand* cmd) {
4567:            case COMMAND_RECTANGLE:
4573:                process_rectangle(cmd);
4615:            case COMMAND_RECTANGLE_GRADIENT_H:
4621:                process_rectangle_gradient_h(cmd);
4623:            case COMMAND_RECTANGLE_GRADIENT_V:
4629:                process_rectangle_gradient_v(cmd);

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

3875 static void process_rectangle(const DrawCommand* cmd) {
3876        float x = cmd->params[0];
3877        float y = cmd->params[1];
3878        float w = cmd->params[2];
3879        float h = cmd->params[3];
3880        float stroke = cmd->params[4];  // 0 = filled, >0 = outline thickness
3881    
3882        // Add padding for anti-aliasing (1-2 pixels) + stroke width
3883        float pad = 2.0f + stroke;
3884    
3885        // Quad size in local space (including padding)
3886        float quad_w = w + 2.0f * pad;
3887        float quad_h = h + 2.0f * pad;
3888    
3889        // Rectangle corners with padding (local coordinates)
3890        // 0---1
3891        // |   |
3892        // 3---2
3893        float lx0 = x - pad, ly0 = y - pad;
3894        float lx1 = x + w + pad, ly1 = y - pad;
3895        float lx2 = x + w + pad, ly2 = y + h + pad;
3896        float lx3 = x - pad, ly3 = y + h + pad;
3897    
3898        // Transform to world coordinates
3899        float wx0, wy0, wx1, wy1, wx2, wy2, wx3, wy3;
3900        transform_point(cmd->transform, lx0, ly0, &wx0, &wy0);
3901        transform_point(cmd->transform, lx1, ly1, &wx1, &wy1);
3902        transform_point(cmd->transform, lx2, ly2, &wx2, &wy2);
3903        transform_point(cmd->transform, lx3, ly3, &wx3, &wy3);
3904    
... [20 more lines]

Let me check the SDF shader fragment behavior — does it discard outside the rect or just blend?

Grep ("discard"|discard;|alpha.<.0.|SHAPE_TYPE_RECT)

2211:#define SHAPE_TYPE_RECT     0.0f
3921:                       SHAPE_TYPE_RECT, shape,
3973:                                SHAPE_TYPE_RECT, shape);
4024:                                SHAPE_TYPE_RECT, shape);
9682:    "        discard;\n"

Read (E:\a327ex\Anchor2\engine\src\anchor.c)

9670     "        v[7] = vShape4.zw;\n"
9671        "        d = sdf_polygon(local_p, v, n);\n"
9672        "    } else if (vType < 6.5) {\n"
9673        "        // Rounded Rectangle: shape0 = (quad_w, quad_h, half_w, half_h), shape1 = (radius, stroke, _, _)\n"
9674        "        vec2 quad_size = vShape0.xy;\n"
9675        "        vec2 local_p = vUV * quad_size;\n"
9676        "        vec2 center = quad_size * 0.5;\n"
9677        "        vec2 half_size = vShape0.zw;\n"
9678        "        float radius = vShape1.x;\n"
9679        "        stroke = vShape1.y;\n"
9680        "        d = sdf_rounded_rect(local_p, center, half_size, radius);\n"
9681        "    } else {\n"
9682        "        discard;\n"
9683        "    }\n"
9684        "    \n"
9685        "    // Apply stroke (outline) if stroke > 0\n"
9686        "    if (stroke > 0.0) {\n"
9687        "        d = abs(d) - stroke * 0.5;\n"
9688        "    }\n"
9689        "    \n"
9690        "    // Apply anti-aliasing (or hard edges when u_aa_width = 0)\n"
9691        "    // vColor is multiply (tint), vAddColor is additive (flash)\n"
9692        "    float alpha;\n"
9693        "    if (u_aa_width > 0.0) {\n"
9694        "        alpha = 1.0 - smoothstep(-u_aa_width, u_aa_width, d);\n"
9695        "    } else {\n"
9696        "        alpha = 1.0 - step(0.0, d);\n"
9697        "    }\n"
9698        "    FragColor = vec4(vColor.rgb + vAddColor, vColor.a * alpha);\n"
9699        "}\n";

Grep (u_aa_width|aa_width)

4482:    // Set u_aa_width for this layer's filter mode. The default draw shader is
4485:    // Shape and sprite/glyph branches both branch on u_aa_width.
4487:    GLint aa_loc = glGetUniformLocation(shader_program, "u_aa_width");
4488:    float aa_width = (layer->filter_mode == FILTER_SMOOTH) ? 1.0f : 0.0f;
4489:    glUniform1f(aa_loc, aa_width);
9524:    "uniform float u_aa_width;\n"
9600:    "        if (u_aa_width == 0.0) {\n"
9613:    "        if (u_aa_width == 0.0) {\n"
9625:    "        if (u_aa_width == 0.0) {\n"
9690:    "    // Apply anti-aliasing (or hard edges when u_aa_width = 0)\n"
9693:    "    if (u_aa_width > 0.0) {\n"
9694:    "        alpha = 1.0 - smoothstep(-u_aa_width, u_aa_width, d);\n"
10300:        GLint aa_loc = glGetUniformLocation(shader_program, "u_aa_width");
10301:        float aa_width = (filter_mode == FILTER_SMOOTH) ? 1.0f : 0.0f;
10302:        glUniform1f(aa_loc, aa_width);
10722:            GLint aa_loc = glGetUniformLocation(shader_program, "u_aa_width");
10723:            float aa_width = (filter_mode == FILTER_SMOOTH) ? 1.0f : 0.0f;
10724:            glUniform1f(aa_loc, aa_width);

Found it. The SDF shader doesn't discard outside the rect — it just modulates alpha. But the stencil write happens regardless of alpha (the fragment still reaches the stencil op stage). The rectangle's quad is padded 2 pixels beyond the requested rect on each side (for AA room), so the stencil mask actually marks 1 in a region 2 pixels larger than the canvas rect — which is why your image bleeds about 2 pixels into Panel A's border.

Single-line fix: inset the stencil mask rect by 2 pixels so its padded quad lands exactly at the canvas boundary.

Edit (E:\a327ex\Anchor2\app\panes\canvas.lua)

The file E:\a327ex\Anchor2\app\panes\canvas.lua has been updated successfully. (file state is current in your context — no need to Read it back)

Bash (cd E:/a327ex/Anchor2/app && /e/a327ex/Anchor/reference/love-compare/tools/lua54....)

OK
Initialization complete. Press ESC to exit, F11 for fullscreen.
Headless loop starting...
Shutting down...

Try again — image should now stop exactly at the canvas's right edge, no bleed into Panel A.

Two things I want to flag:

This is a hack. The proper fix is engine-side: have the SDF shader discard fragments where alpha is fully zero (so stencil writes don't happen in the padding). That'd fix it for any future stencil use, not just canvas. But the inset is a one-line workaround that gets us moving. I'll note it as a deferred engine fix.
Layer of nuance: if there's any AA fade at the boundary itself (d ≈ 0), stencil writes there too. That should be sub-pixel — invisible. But if you look very carefully and see a very faint 1-pixel bleed, that's the shader-discard fix territory. For now, 2-pixel inset is close enough.

Let me know if the bleed is gone or if there's still visible overlap.

Great, everything else seems to work.

Sub-step 7b is solid. Quick recap of what shipped this session:

This session:

Engine additions: drop events, cursor API, focus-clickthrough, stencil clear on mask
Content store (FNV-1a hash, blob storage)
Canvas pane: drop, display, select, move, 8-handle resize, stencil clipping, cursors, persistence, delete, undo/redo (Ctrl+Z, Ctrl+R)
Workspace bug fix (saved state merging with mode defaults)
Model layer (generic registry with version counters)
Two-pane model-view sharing (split mode, F4)
Canvas-local coordinates (proper embedded-view foundation)
Workspace-level drop routing
2-pixel SDF stencil-bleed workaround

That's a lot. We've validated the model-view architectural bet — two panes pointing at the same canvas model show identical content with independent view state. Step 7 is done.

Two ways forward

Option A: Continue with step 8 (embedded views) now.

Step 8 is what makes "embed a game inside a blog post" possible. It's bigger than 7b:

Generalize where a pane can be hosted. Currently a pane lives in a workspace slot. Step 8 adds a second host: a canvas element of type embedded_view. The element has bounds (x, y, w, h) and a pane_id; rendering the element invokes the inner pane's update with the element's window-space rect.
Recursive input routing: when the cursor is over an embedded_view element on the outer canvas, mouse events should route to the inner pane, not the outer canvas's selection/drag logic.
Recursive stencil clipping: the embedded pane's rendering should clip to its element's bounds (already works for our canvas because we use layer_push + stencil — same mechanism naturally recurses).
Outer-canvas chrome around the element: the embedded_view element is still a canvas element with corners/selection/etc. — the resize handles let you adjust the embed's frame size, which automatically tells the inner pane it has a different rect.
The inner pane's own canvas-local coords mean the embedded view shows its content anchored to the element's top-left.

Realistically 150–250 lines across canvas + pane modules. Probably one more focused session.

Option B: Pause here.

We're at a clean architectural point — model layer works, two views of one model works. Step 8 builds on it but is meaningful work. Picking it up fresh would be cleaner than rushing it after this long session.

If we pause, next session is:

Step 8 (embedded views).
Step 9 (view clipboard — Cmd+Shift+C captures focused pane's state, Cmd+Shift+V instantiates it as an embedded_view element or in a slot).
Then text editing (part 3 of Phase 1) per your earlier plan.

My honest read: B. This is a real natural pause. Step 8 deserves its own focused start, and we've stress-tested a lot of architectural pieces in this session that all need to be living-tested in real workflows before we layer more on top.

But you decide. Which way?

I don't understand what step 8 is actually doing that's different from what we already have, could you explain?

Fair question — the line is genuinely thin if I describe it abstractly. Let me draw it concretely.

What we have now

Panes live in workspace slots:

┌─ split mode ─────────────────────────────────────────┐
│ status_top                                           │
├──────────┬──────────────┬────────────────────────────┤
│ canvas_b │   panel_a    │      main_canvas           │
│          │              │                            │
│ (slot:   │ (slot:       │ (slot:                     │
│  canvas_ │  middle)     │  canvas_right)             │
│  left)   │              │                            │
│          │              │                            │
├──────────┴──────────────┴────────────────────────────┤
│ status_bot                                           │
└──────────────────────────────────────────────────────┘

The slots are template-defined. The template says "there's a slot at left-edge 600px, another at right-edge 600px, middle is fill." Switching modes switches templates. The slots are layout-driven, not content-driven.

When you put canvas_b and main_canvas in two slots, you have two panes side by side in the workspace — both viewing the same canvas model. That's step 7.

What step 8 adds

A pane can also live inside another canvas as one of its elements, positioned freely like an image:

canvas_a (a "document"):
  elements = {
    {type='image',         blob_id='blob:abc.png', x=10, y=10, w=400, h=300},
    {type='image',         blob_id='blob:def.png', x=50, y=400, w=300, h=200},
    {type='embedded_view', model_id='canvas:game', x=450, y=20, w=400, h=300},
                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                                              a CANVAS PANE living inside another canvas,
                                              at position (450, 20), size 400x300
  }

That third element is a live pane embedded as content. It's not a workspace slot. It's a canvas element, just like the image elements. It scrolls with the canvas, persists in the canvas's saved file, has resize handles, can be moved around.

Why that's different

Slot vs element — different worlds:

	Slot (now)	Canvas element (step 8)
Defined by	Template (mode-level)	Canvas content (document-level)
Position	Fixed by mode	Free, like an image element
Persistence	`.workspace_state.lua`	The canvas's own `scratch.lua`
Lifecycle	Lives across modes	Lives with its canvas
Switching modes	Pane moves/hides	Element doesn't care
Use case	App-level layout	"This canvas has a game in it"

Concrete example matching your goal

You said: "I can post a game inside a blog post. The game is its own frame, and we a copy of this frame into a blog post."

With only what we have today, that workflow can't exist. The blog post is a canvas. The game is a canvas. To put the game in the post, the game has to be one of the post's elements. Right now elements can only be images. The blog post canvas can't contain the game canvas.

With step 8:

You author a game in a canvas (say 'canvas:game42'). Drop sprites, run logic, whatever.
You author a blog post in another canvas (say 'canvas:post-2025-03-01').
In the blog post canvas, you drop an embedded_view element at position (200, 600), size 480x360, pointing at 'canvas:game42'.
Now when you view the blog post canvas, the game runs inline at that position. Resize the element → game viewport gets smaller/larger. Move the element → game moves with it. Delete the element → game stays in 'canvas:game42', just no longer embedded here.
When the blog post is exported to a327ex.com (Phase 5), the embedded_view element becomes a <canvas> (or similar) on the page running the same game.

Without step 8, your only option is "show the blog post canvas in one slot and the game in another slot side by side." But that's a workspace layout, not a blog post. The game isn't in the post. It's a parallel pane.

What changed since step 7

What 7b proved is the plumbing: two views of one model. Step 8 uses that plumbing to make panes embeddable. The model-view split is what lets 'canvas:game42' show up identically whether it's in a workspace slot (your editing view) or embedded as content of 'canvas:post-2025-03-01' (your published view). Both are pointing at the same model; both render the same content; one happens to live in the workspace, the other lives inside a document.

So:

Step 7 = a pane can have multiple instances of itself simultaneously, all in sync.
Step 8 = a pane can live inside content, not just next to other panes.

Make sense?

Ah, right, this makes sense and is highly necessary. Let's pause here. Update any documentation files, then let's end the session, name it Anchor App Phase 1 Part 2

Updating docs first, then ending the session.

Read (E:\a327ex\Anchor2\app\plan.md)

34   ## Current Status (2026-04-17)
35  
36  Written after the first design pass. Older sections below this header reflect
37  the original thinking; a few specifics are now settled and flagged in-place.
38  If you are a future session picking this up, read in this order:
39  
40  1. This file, for the 10-phase build plan + vision.
41  2. `Anchor2/app/docs/ui_architecture.md` — **UI system architecture** decisions (workspace/panes/slots/widgets, model–view separation, hosts, focus, view clipboard, RectCut layout). Captured 2026-04-28. Most of these decisions are non-obvious from the codebase and are load-bearing.
42  3. `Anchor2/app/docs/visual_identity.md` — palette, typography, density, chrome, per-phase UI inventory. §8 lists **locked decisions**; §9 indexes every mockup; §10 documents reusable UI patterns.
43  4. `Anchor2/app/docs/mockup_v2_ui_kit.html` — **authoritative visual reference**. Implement to match. `mockup_v2_canvas.html` is a composition example. Older v1 mockups (`mockup.html` etc.) are superseded.
44  5. `Anchor2/.claude/CLAUDE.md` — framework-v2 coding disciplines (procedural modules, ID-based cross-refs, explicit destroy, no object tree).
45  
46  **What's done:**
47  - Engine Track B partial: per-layer and per-font `filter_mode`, so a single frame can mix smooth (AA) canvas UI with rough (pixel-perfect) embedded game views. Shipped 2026-04-17.
48  - `Anchor2/app/` scaffolded with a smooth-vs-rough demo (`main.lua`). Runs at 1440×900 / scale=1 / smooth. Demonstrates the engine fixes; not the Phase 1 app itself.
49  - Visual identity committed: Catppuccin-Macchiato-derived navy palette, IBM Plex Sans + IBM Plex Serif + Cascadia Code, mid-dense chrome, 0–2px radius, 1px borders, no shadows, depth via bg-color differentiation. See `docs/visual_identity.md`.
50  - Six mockup HTML files built to lock the look: main canvas, book-with-game, agent-UX comparison, write mode, code editor, piano roll.
51  
52  **What's next:**
53  - Phase 1 Foundation implementation. **Plan revised 2026-04-28**: skip the canvas-and-element work for now and implement the UI kit primitives first, exactly as drawn in `docs/mockup_v2_ui_kit.html`. The kit is the authoritative source for chrome (status bars, palette, type, buttons, inputs, chips, list rows, selection, agent identities). Once the kit primitives render correctly the canvas + element layer drops on top of them.
54  - First slice: top status bar (24px) + bottom status bar (22px) + body bg, against the v2 UI kit visual reference. Exercises the whole pipeline (smooth layer at framebuffer size, palette, smooth fonts, primitives) and matches the chrome that's on every v2 mockup.
55  
56  **Locked since original draft (supersedes older text below):**
57  - Filesystem is **tag-based, no folders** (see Phase 3 revision).
58  - Music composition lead view is **sheet-music / code-based**, not piano roll (see Phase 8 revision).
59  - Agent UX is the **global right-side panel** for v1. Per-element popover/strip variants are mocked but deferred.
60  - Target hardware: single 1440×900 window initially; multi-monitor eventually.
61  - **Authoritative visual reference is `docs/mockup_v2_ui_kit.html`** for primitives and `docs/mockup_v2_canvas.html` as a composition example. The older v1 mockups (`mockup.html` etc.) are superseded.
62  - **Resolution model**: see `## Resolution Model` below. UI code is written in raw logical pixels; the engine handles device-pixel sizing of smooth FBOs and font atlases via a per-window `dpr` factor. dpr=1 today on a single monitor, so behavior matches "just draw at native pixel size." The engine change to smooth-mode FBO/atlas sizing is deferred until Phase 5 (publishing) or whenever a HiDPI display first appears, but the framework + app code are written today as if it's already in place — i.e. nothing in UI code assumes "1 logical px = 1 device px."
63  
... [35 more lines]

Edit (E:\a327ex\Anchor2\app\plan.md)

The file E:\a327ex\Anchor2\app\plan.md has been updated successfully. (file state is current in your context — no need to Read it back)

Now updating ui_architecture.md to mark the model layer + multi-view as implemented:

Read (E:\a327ex\Anchor2\app\docs\ui_architecture.md)

1    # Anchor App UI Discussion
2   
3   Captured 2026-04-28. Authoritative reference for the app's UI architecture.
4   If you are a future session picking this up, read this file *after* `plan.md`
5   and *before* writing any UI code — most of the decisions here are non-obvious
6   from the codebase alone and were settled by long discussion.
7   
8   The visual side of the UI is covered separately: see `docs/visual_identity.md`
9   and `docs/mockup_v2_ui_kit.html` (the authoritative visual reference). This
10  file is the *system architecture*: how the UI is structured in code, what the
11  units of composition are, how state flows between them.
12  
13  ---
14  
15  ## TL;DR
16  
17  - **Hybrid mode UI**: retained workspace shell (panes are long-lived stateful objects you can drag between slots) + immediate-mode widget functions inside panes (buttons, chips, rows — drawn each frame from state).
18  - **Two-tier layout**: a workspace template defines named **slots** (edge slots + one fill slot); each mode assigns specific **panes** to those slots. Slot names are positional and generic (`side_a`, `main`, `status_top`); pane names are stable identities (`code_editor`, `agent_oracle`).
19  - **RectCut** is the layout primitive inside panes. Small module (~50 lines), mutating-parent style, supplemented by helpers (contract, center, split_h/v).
20  - **Model–view separation**: a separate model layer holds files, documents, agent conversations. Panes are *views* of models. Multiple panes can view the same model; edits propagate via per-frame version polling.
21  - **Two host types** for panes: workspace slot host (full chrome) or canvas-element host (panes embedded as content inside documents). Same pane class either way.
22  - **Resolution model**: UI code in raw logical pixels; engine handles device-pixel sizing of smooth FBOs and font atlases via a `dpr` factor (1.0 today). See `plan.md` § Resolution Model.
23  - **Authoritative visual reference**: `docs/mockup_v2_ui_kit.html`. Older v1 mockups superseded.
24  
25  ---
26  
27  ## 1. Why this shape
28  
29  The UI sits in the awkward middle of the action-based vs rules-based gameplay
30  spectrum (per the author's essay on the topic). Different *scopes* of the UI
... [10 more lines]

Edit (E:\a327ex\Anchor2\app\docs\ui_architecture.md)

The file E:\a327ex\Anchor2\app\docs\ui_architecture.md has been updated successfully. (file state is current in your context — no need to Read it back)

Docs updated. Invoking the end-session skill:

Skill

Launching skill: end-session

Base directory for this skill: E:\a327ex.claude\skills\end-session

End Session Workflow

This skill is invoked from the same conversation where the work was done. You already have the full session context in memory — you do NOT need to read the transcript.

Step 1: Get Session Info

Ask the user for the session title (max 30 characters). Examples: "Anchor Phase 10 Part 5", "Physics Arena Setup", "Timer System Fix", "Thalien Lune Design".

Determine the project yourself from your session context — you know which repo(s) were worked on, which files were created/modified, and where they live. No need to ask. See Step 5 for the list of known project roots; if the session touched something outside the list, infer the root from the paths you actually edited.

Step 2: Write Summary

Write the summary from your conversation memory. You have the full session context — no need to read any files.

The summary should be thorough and detailed. Each major topic deserves its own section with multiple specific bullet points. Don't compress — expand.

Purpose: These summaries serve as searchable records. Future Claude instances will grep through past logs to find how specific topics were handled. The more detail you include, the more useful the summary becomes for finding relevant context later.

Format (this is just an example structure — adapt sections to match what actually happened):
# [Title]

## Summary

[1-2 sentence overview of the session's main focus]

**[Topic 1 - e.g., "Spring Module Implementation"]:**
- First specific detail about what was done
- Second detail - include file names, function names
- User correction or feedback (quote if notable)
- Technical decisions and why

**[Topic 2 - e.g., "Camera Research"]:**
- What was researched
- Key findings
- How it influenced implementation

**[Topic 3 - e.g., "Errors and Fixes"]:**
- Specific error message encountered
- Root cause identified
- How it was fixed

[Continue for each major topic...]

---

[Rest of transcript follows]
Rules: - Be thorough — If in doubt, include more detail, not less. Each topic should be as detailed as possible while still being a summary. - Think searchability — Future instances will search these logs. Include keywords, function names, error messages that someone might grep for. - One section per major topic — Don't combine unrelated work into one section - Chronological order — Sections should match conversation flow - Specific details — Error messages, file names, function names, parameter values - Include user quotes — When user gave notable feedback, quote it (e.g., "k/d variables are not intuitive at all") - Weight planning equally — Research, proposals, alternatives considered, user feedback on approach are as important as implementation - Weight problems solved — Errors, root causes, fixes, user corrections all matter - Technical specifics — Include formulas, API signatures, parameter changes when relevant

Step 3: Get User Approval

Show the title and summary to the user. Wait for approval before proceeding. If they have corrections, fix them.

Step 4: Convert Transcript and Write the Log File
# Find recent sessions (Claude + Cursor + Codex). Same script lives in Anchor2:
python E:/a327ex/Anchor2/scripts/find-recent-session.py --limit 5
# or: python E:/a327ex/Anchor/scripts/find-recent-session.py --limit 5
The script shows sessions sorted by when they ended. The first result is the current conversation (since end-session was invoked here). Use it.

Use a lowercase hyphenated slug derived from the title (e.g., "anchor-primitives-hitstop-animation").

Get the end timestamp for the Date frontmatter — this is the wall-clock time when end-session was invoked, NOT the time the JSONL started. Sessions often span multiple days, and the log should be filed under the day the work was wrapped up:
date "+%Y-%m-%d %H:%M:%S"
Use this output verbatim. Do not substitute the JSONL start timestamp; the log appears in the sidebar sorted by Date, and a multi-day session with a Date pinned to day 1 will sort below sessions that ended later but started later, hiding the most recent work.

Convert the transcript to markdown:
python E:/a327ex/Anchor2/scripts/jsonl-to-markdown.py [SESSION_PATH] /tmp/session-log.md
# or: python E:/a327ex/Anchor/scripts/jsonl-to-markdown.py ...
The same script auto-detects Claude Code JSONL vs Cursor/Composer agent JSONL (~/.cursor/projects/.../agent-transcripts/...) vs Codex rollouts (~/.codex/sessions/...). For Composer sessions, use find-recent-session.py (it merges all sources) and pick the [cursor] line for the current chat.

Replace the default header (# Session YYYY-MM-DD...) at the top of /tmp/session-log.md with the approved title and summary, AND prepend frontmatter. The final file shape:
Title: [Title]
Date: YYYY-MM-DD HH:MM:SS

# [Title]

## Summary

[approved summary text from step 2]

---

[transcript content from jsonl-to-markdown script]
Frontmatter is non-negotiable. Every log file MUST start with Title: and Date: lines. Without them, the site's sidebar shows the slug as the title and 0 (epoch) as the sort date. The backfill script in a327ex-site/deploy/backfill_metadata.py is a safety net, not a substitute — write it correctly the first time.

Then copy the final file to the log destination:
cp /tmp/session-log.md E:/a327ex/a327ex-site/logs/[slug].md
Step 5: Commit Project Repo

Identify the project repo(s) worked on this session from your own context — you already know which repos were touched and which files changed. For the common projects:

Project Root Stage command

Anchor E:/a327ex/Anchor git add docs/ framework/ engine/ scripts/ reference/

Anchor2 E:/a327ex/Anchor2 git add framework/ engine/ arena/ reference/ scripts/ docs/ .claude/

emoji-ball-battles E:/a327ex/emoji-ball-battles git add -A

orblike E:/a327ex/orblike git add -A

thalien-lune E:/a327ex/thalien-lune git add -A

a327ex-site E:/a327ex/a327ex-site git add -A (this IS one of the web repos — the log file added in Step 4 is staged here automatically)

For a project not listed, infer the root from the files you actually created or modified this session and stage those. If multiple candidate roots look valid, ask the user which files to stage.

cd into the project root, stage, run git status to verify before committing.

IMPORTANT — FULL SUMMARY IN COMMIT: The commit message MUST include the FULL summary from the log file. Read the summary back from the log file to ensure nothing is missing.

IMPORTANT — COMMIT METHOD: The summary contains backticks, special characters, and markdown that WILL break heredocs and git commit -m. ALWAYS use the file-based method below. NEVER try a heredoc first — it will fail and produce a malformed commit that needs amending.
# Skip until we hit the line "## Summary", then take everything after the next
# blank line until the --- separator that precedes the transcript.
awk '/^## Summary$/{found=1; next} found && NR>1 && /^---$/{exit} found' \
    E:/a327ex/a327ex-site/logs/[slug].md > /tmp/commit_msg.txt

# Prepend the title (plain text, no #) and append attribution
sed -i "1i [Title]\n" /tmp/commit_msg.txt
printf "\nGenerated with [Claude Code](https://claude.com/claude-code)\n\nCo-Authored-By: Claude <noreply@anthropic.com>\n" >> /tmp/commit_msg.txt

git commit -F /tmp/commit_msg.txt
Step 6: Push the Repos

Two pushes — project (to GitHub) and a327ex-site (to the VPS):
# Project repo to GitHub. Skip this push if the project IS a327ex-site
# (handled by the second push below — don't duplicate).
git push origin main

# a327ex-site to the VPS (post-receive hook restarts the Lua server).
cd E:/a327ex/a327ex-site
git add -A
git commit -m "[Title]"
git push prod main 2>&1 | tail -3
Failure handling: if either push fails, the other still happens. Local commits stay intact, so the user can re-push manually once they've fixed whatever blocked it. Don't roll back; the committed state on disk is the source of truth.

Step 7: Confirm

Tell the user: - Project commit hash + GitHub push result - a327ex-site commit hash + VPS push result

Format:
Logged — "[Title]".
  project (Anchor2):  abc1234  pushed to GitHub
  a327ex-site:        ghi9012  pushed to a327ex.com (post-receive deployed)
If a push failed, surface that explicitly with the error.

Notes

Frontmatter is non-negotiable. Every log file MUST have Title: and Date: at the top. Enforced at write time in step 4. The backfill script is a safety net, not a substitute.

If the project IS a327ex-site (e.g., you spent the session writing the renderer or fixing the theme), there's no separate "project repo to GitHub" push — the a327ex-site push at the end IS the project push. Don't duplicate.

Legacy note: this skill used to also dual-write to anchor.blot.im/logs/ and anchor.blot.im/context/. Post-cutover (May 2026), anchor.blot.im is a JS redirect to a327ex.com and no longer receives content. Drop those steps if you find any older docs that still reference them.

ARGUMENTS: Anchor App Phase 1 Part 2

Project	Root	Stage command
Anchor	`E:/a327ex/Anchor`	`git add docs/ framework/ engine/ scripts/ reference/`
Anchor2	`E:/a327ex/Anchor2`	`git add framework/ engine/ arena/ reference/ scripts/ docs/ .claude/`
emoji-ball-battles	`E:/a327ex/emoji-ball-battles`	`git add -A`
orblike	`E:/a327ex/orblike`	`git add -A`
thalien-lune	`E:/a327ex/thalien-lune`	`git add -A`
a327ex-site	`E:/a327ex/a327ex-site`	`git add -A` (this IS one of the web repos — the log file added in Step 4 is staged here automatically)

Drafting the summary now for your approval.

Anchor App Phase 1 Part 2

Summary

Session orientation:

Picked up from Phase 1 Part 1 (workspace shell, panes/slots/templates, drag-to-swap, modes, persistence).
User chose path B from the prior session's options: build one concrete pane type — a free-flowing canvas with external-source image drops — to test references-of-content questions and prepare for the model–view architecture work.
Decided to skip the cross-app drop deep-dive (custom Win32 OLE drop handler) after surfacing that SDL2's drop target only accepts CF_HDROP + CF_UNICODETEXT + CF_TEXT, which means browser/Discord drags showing custom Chromium/Mozilla formats get rejected with a stop-sign cursor. Workaround for now: save-to-disk then drag from Explorer.

Engine: drag-and-drop event capture (sub-step 1):

Added SDL_DROPFILE event handling to anchor.c's main SDL_PollEvent loop. Bounded queue (32 paths × 1024 chars) static-allocated; SDL allocates event.drop.file and we copy + SDL_free immediately. New Lua function engine_get_dropped_files() returned the queued paths and drained the queue (later renamed/refactored).
Sub-step 1.5 added SDL_DROPTEXT support alongside SDL_DROPFILE for the cross-app investigation. Refactored to unified drops[] table with DropKind enum (DROP_KIND_FILE / DROP_KIND_TEXT) and renamed Lua function to engine_get_drops() returning list of {kind='file'|'text', value='...'} tables.

Engine: cursor API:

Added engine_set_cursor(name) exposing SDL system cursors: 'arrow', 'ibeam', 'wait', 'crosshair', 'waitarrow', 'sizenwse', 'sizenesw', 'sizewe', 'sizens', 'sizeall', 'no', 'hand'. Cursors created lazily on first use and cached in a static array cursor_cache[SDL_NUM_SYSTEM_CURSORS] keyed by SDL_SystemCursor enum. Safe to call every frame — SDL no-ops if cursor unchanged.

Engine: focus-clickthrough:

Set SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH = "1" before SDL_Init so the first click on an unfocused window after returning from Explorer/another app passes through as a real click instead of being eaten by Windows just refocusing the window.

Engine: stencil clear on mask:

Added glClearStencil(0); glClear(GL_STENCIL_BUFFER_BIT); to the COMMAND_STENCIL_MASK case in anchor.c. Without this, sequential mask calls in a single frame accumulate (union of all rects) — two canvas panes each defining their own clip would let each pane's draws bleed into the other's rect.
Known limitation discovered but not fixed engine-side: the SDF rect fragment shader doesn't discard fully-transparent fragments, so stencil writes happen across the rect's 2-pixel AA padding, causing ~2-pixel stencil bleed past the requested rect. Worked around in canvas.lua by insetting the stencil mask shape by 2 pixels (SDF_PAD = 2).

Content store (content_store.lua):

File-content-addressed blob storage at app/data/blobs/<hex>.<ext>. FNV-1a 64-bit hash of file contents as identifier (placeholder; should be replaced by engine SHA-256 once Track B's HTTP client lands).
Opaque blob IDs (blob:<hex>.<ext>) — paths never leak into documents. Server-friendly: the same hash maps to a local file today and could map to https://a327ex.com/blobs/<hash>.<ext> on the future server with the resolver as the only thing that changes.
API: content_store_init() (idempotent mkdir), content_store_put(source_path) → blob_id, err (hash + copy, dedups by hash), content_store_path(blob_id), content_store_resolve(blob_id) → image.
Image extensions whitelist: png, jpg, jpeg, gif, webp, bmp.

Canvas pane initial implementation (sub-step 2):

app/panes/canvas.lua — element list with {type='image', blob_id, image, x, y, w, h} shape.
Initial drop position centered at cursor, native pixel size on drop (later changed; first version had MAX_INITIAL_SIZE = 600 cap which user pushed back on).
Stencil clipping confines content to the canvas rect using layer_stencil_mask / layer_stencil_test / layer_stencil_off.
Drop processing: gated on cursor inside the canvas rect (later moved to workspace-level routing).

Bug: os.execute cwd discovery:

content_store_init() initially tried mkdir "app\\data\\blobs" from Lua expecting cwd = Anchor2/. Debug prints revealed the engine does _chdir(game_folder) at startup — so when launched as ./app/anchor.exe app, cwd becomes Anchor2/app/. Fixed by using paths relative to app/ (e.g., data/blobs not app/data/blobs).
Also discovered that the workspace persisted state file .workspace_state.lua lives at Anchor2/app/.workspace_state.lua (not Anchor2/.workspace_state.lua as initially assumed).

Bug: Lua C-API stack index in l_engine_get_drops:

Heisenbug crashing on first drop. User reported "Segmentation fault" with no Lua error and no canvas trace prints.
After adding aggressive io.write + io.flush traces narrowing it down, found the actual crash was layer_draw_texture failing — but discovered an earlier latent bug in the engine.
Root cause: l_engine_get_drops had lua_rawseti(L, -3, i+1) but the stack only had [outer, inner] at that point — -3 is below the function's stack base. With release Lua's API checks compiled out, it was reading garbage memory as a Table*. Worked "by luck" in sub-step 1.5 but crashed in sub-step 2. Fixed by changing -3 → -2.
User: "no Lua error even" — pointed straight to C-side UB.

Bug: layer_draw_texture no framework wrapper:

After fixing the stack bug above, image drops still crashed. Trace prints showed crash at layer_draw_texture(ui_layer, el.image.handle, 0, 0).
Root cause: layer_draw_texture is the raw engine binding expecting a Layer* lightuserdata as arg 1. ui_layer is the Lua table {name, handle, filter, ...} returned by layer_new. lua_touserdata returns NULL for non-userdata → engine deref of NULL Layer pointer → segfault.
The framework wraps layer_rectangle, layer_push, layer_pop, layer_image, layer_texture etc. but NOT layer_draw_texture — the global layer_draw_texture is unshadowed. The anchor/layer.lua file's own header explicitly warns about this name-collision footgun.
Fix: use layer_image(ui_layer, el.image, 0, 0) (framework wrapper that extracts .handle and img.handle) instead of layer_draw_texture.

Sub-step 2 size policy change:

User noticed initial 717×477 image was being rendered at 599×399 (MAX_INITIAL_SIZE = 600 cap on largest dimension).
First fix: change cap to slot-aware (s = math.min(1, rect.w/w, rect.h/h)).
User pushed back: "Save native size... 2 also solves 1, we don't need to actually resize the image, the user can do that automatically. Once the image spawns, it's full size, if it goes beyond the slot, the user can diminish it themselves."
Final fix: no auto-shrink. Image spawns at native size. Stencil clip hides overflow. User resizes via handles (later) or keybinds (future).

Sub-step 3a: selection:

Click on element body → select topmost (last in elements list, drawn last) under cursor. Click empty → deselect. Ctrl+click skipped (workspace pane-swap).
Selection visual: 1px lavender ring around element bounds. Drawn inside stencil block so it clips with the image.
Hit-test in reverse order so the visually-topmost element wins.

Sub-step 3b: drag-to-move:

Single click handler covers both select + drag-start: clicking an element selects it AND captures cursor offset for the move drag. Mouse release ends the drag.
Drag mutates el.x / el.y in place each frame while state == 'moving'. Free positioning — element keeps real coords even when dragged off-canvas; stencil clip handles visuals.
Plain LMB drag = move element; Ctrl+LMB drag = workspace pane swap. The Ctrl gate disambiguates.

Sub-step 3 (continued): resize handles with corner + edge squares:

User requested: corner squares to scale + aspect-preserving, edge bands to resize-in-one-axis-with-aspect-preserved, visible markers, system cursor changes on hover.
Eight handles: 4 corner squares (always drawn) + 4 edge midpoint squares (only drawn when el.w >= s*3 / el.h >= s*3 so they don't overlap corners).
Made squares render INSIDE the image (anchored to the corresponding edge/corner growing inward) so they're never clipped at canvas boundaries — user explicitly asked for this.
HANDLE_SIZE = 8, EDGE_HIT = 6, MIN_SIZE = 24 (sized so 4 corners + edge midpoint can fit without overlapping diagonally).
Resize math: corners use scale = max(dw/orig_w, dh/orig_h, min_scale) — cursor leads on whichever axis dragged faster, opposite corner anchored. Edges use single-dim scale, opposite edge + orthogonal center anchored.
Captured pre-drag geometry at drag start (self.drag.pre = {x,y,w,h}) for undo command on release.
Cursor changes via CURSOR_FOR_HANDLE map: corner_tl/br → sizenwse, corner_tr/bl → sizenesw, edge_top/bot → sizens, edge_left/right → sizewe. Set every frame; engine's SDL_SetCursor no-ops when unchanged.

Sub-step 3c: persistence:

Canvas saves to app/data/canvases/scratch.lua as Lua return-table after every mutation (drop, drag-end, resize-end). Save triggers from undo commands' apply/revert.
Saved per element: {type='image', blob_id, x, y, w, h} — not the live image userdata (can't serialize).
Load on pane init: read_canvas_elements(path) parses + validates + re-resolves each blob_id via content_store_resolve. Elements with missing blobs are skipped with a stderr warning rather than aborting the whole load.
Hand-readable file with version = 1 file-format-version (separate from the runtime model version counter that came later).
Atomic writes deemed overkill for personal-use local-disk app.

Delete key:

Pressing Delete on a selected element removes it via a delete command. Bound to dedicated Delete key only (not Backspace — reserved for text-element editing in Part 3). Selection clears.

Undo / redo (sub-step 3 supplement):

New undo.lua module: global undo_stack + redo_stack, MAX_UNDO = 256, LIFO. New action clears redo stack.
Commands are tables with apply and revert methods. "Apply on push" pattern for add/delete (gesture creates cmd, calls apply, pushes). "Already applied" pattern for move/resize (gesture mutates in place during drag, cmd captures pre + post state at drag-end, pushes without calling apply).
Four canvas command types: make_add_command (insert/remove), make_delete_command (remove/re-insert at saved index), make_move_command (set x,y), make_resize_command (set x,y,w,h).
Commands target by pane_id (stable string) and elements by table identity (remove_by_identity helper). Robust against reordering.
Bound Ctrl+Z → undo, Ctrl+R → redo (user changed from Ctrl+Shift+Z / Ctrl+Y).
Handler lives at workspace level (handle_undo_keys) since undo stack is global, not pane-scoped.

Workspace bug: ensure_per_mode_state didn't merge defaults:

Discovered when split mode showed empty main slot for bare mode after a previous session's saved state had main_placeholder (which no longer existed). The validation in workspace_load_state stripped the invalid pane id, leaving the slot empty. ensure_per_mode_state then early-returned because per_mode[name] existed (just with the missing slot).
Fix: ensure_per_mode_state now merges defaults INTO existing state for any missing slots, rather than skipping. New panes added in code appear next session even with saved state; user's drag-swaps stay intact (their slots remain in saved state).

Sub-step 7a: model layer (model.lua):

New global models = {} registry keyed by stable string id. Each model: {id, kind, version, content}.
API: model_new(id, kind, content) (errors on duplicate id), model_get(id), model_bump(m) (increments version), model_destroy(id).
Procedural style, no event subscription. Views poll model.version per-frame and re-derive when it changes.
Canvas refactor: data moved from self.elements directly on the pane to self.model.content.elements. self.elements kept as a convenient alias (the table reference is stable since we only mutate in place).
canvas_model_load(id) returns existing model (idempotent) or creates from disk file.
canvas_model_id → disk path mapping: 'canvas:scratch' ↔ data/canvases/scratch.lua via canvas_path_for(id) helper. Generalizes to multi-canvas later (different IDs → different files).
Every mutation point bumps the model (commands, in-place drag updates). For drag mutations, bump happens every frame so other views see live updates.

Sub-step 7b: multi-view + split mode:

Two canvas panes (main_canvas and canvas_b) registered in main.lua, both using model_id='canvas:scratch'. Both canvas_model_load() calls return the same model instance.
New split template + mode + F4 keybind. Initially had asymmetric side_a (600) + main (fill) which made the test confusing because the two panes had different sizes. User pushed back.
Selection refactored from index-based (self.selected_idx) to element-reference-based (self.selected_el). Indices shift when another pane deletes earlier elements; refs don't.
Version polling added: at top of update, if self.last_seen_version ~= self.model.version then re-validate selection (clear if selected_el no longer in elements), abort drag if its target disappeared.
Defensive mouse_is_down(1) check in drag handler: if drag state is non-idle but mouse isn't held, missed a release event (e.g., mode switched mid-drag) — bail rather than snap element to cursor.
Workspace-level drop routing: new route_drops(rects) drains engine_get_drops() once at the workspace, looks up the pane under the cursor via slot_at, dispatches via new pane:on_drop(drop, rect) method. Without this, both canvas panes would call engine_get_drops() and whichever ran first would drain the queue for everyone.
pane:on_drop added to pane.lua for the new dispatch.

Stencil clear timing bug (between 7a and 7b):

User: "I can just drag it anywhere, I don't understand what I am supposed to test if I can just drag the image normally."
Initial diagnosis: stencil_mask in engine doesn't clear stencil before defining new mask region; sequential mask calls union instead of redefining. Pane B's element draws (rendered AFTER pane A's chrome) bleed into pane A's rect because the union stencil allowed both rects.
Fix: glClearStencil(0); glClear(GL_STENCIL_BUFFER_BIT); in COMMAND_STENCIL_MASK. Each mask now defines a fresh region.

Visual distinguishability between split-mode canvases:

Even after stencil fix, two panes with the same bg looked identical so user couldn't tell they were two panes. Added optional bg parameter to canvas pane (default theme.bg_base). Set canvas_b's bg to theme.bg_inset (darker variant from Catppuccin Macchiato palette) in main.lua. Subtle boundary now visible.

Coordinate model rethink — window-absolute vs canvas-local:

User: "shouldn't we want both panes to be exactly the same in terms of view? So if we have pane A with only the left portion of an image being drawn, and we have a copy of pane A displaying elsewhere, shouldn't we see that same left portion of the image instead of its right portion? The idea behind this is that I can post a game inside a blog post."
Recognized this as the right architectural critique. Current el.x, el.y were window-absolute → each pane just clipped its rect; same data produced different views in different panes.
Refactor: element coordinates are now canvas-local (relative to the pane's rect origin). Pane renders elements at (rect.x + el.x, rect.y + el.y) via a single outer layer_push(rect.x, rect.y, 0, 1, 1) translation that wraps the element/chrome rendering block. Input translates the other way: cx, cy = mx - rect.x, my - rect.y. All hit-testing, drop position, drag offset, resize anchor math uses canvas-local cx, cy + canvas-local el.x, el.y (same coordinate system).
Net result: two panes of the same size viewing the same canvas show identical content — the property required for embeds.
Existing saved canvas data was window-absolute, would shift visually under new semantics — user instructed to rm data/canvases/scratch.lua.
Updated split mode: equal-sized canvas_left (600) + canvas_right (600) edge slots with a middle fill slot hosting panel_a as filler. User explicitly suggested "separated by something irrelevant in the middle" to make the test obvious.

Stencil bleed (SDF padding bug) workaround:

After canvas-local refactor, user reported image bleeding 2-3 pixels past canvas_left's right edge into panel_a.
Investigation: the engine's SDF rect fragment shader doesn't discard fragments fully outside the rect — alpha just fades to 0. The quad geometry has 2 pixels of padding around the requested rect for AA. With colormask off (stencil mask mode), every fragment in the padded quad still reaches the stencil op and writes 1. Stencil ends up marked across the full padded quad → image draws past the actual rect boundary still pass the stencil test.
Quick workaround in canvas.lua: inset the stencil mask shape by 2 pixels (SDF_PAD = 2) so the padded quad lands exactly at the canvas rect boundary. Commented as a hack with proper fix being a shader-side discard.

Step 8 explanation:

User asked the difference between "two panes view same model" (what we have) and step 8 (embedded views).
Clarified: current setup has panes living in workspace SLOTS — template-defined positions, app-level layout. Step 8 adds a second host: panes can also live as CANVAS ELEMENTS — free-positioned in another canvas's content, persisted with that canvas, like an image.
Concrete use case: "embed game in blog post" requires the game-canvas to be an element of the blog-post-canvas, not just a parallel slot.
Step 8 generalizes the pane-host abstraction. The same pane class works in both hosts; what differs is who calls pane:update(rect) with what rect, and how input routes (recursive routing into the embedded view's rect).

Decision to pause:

After step 7b validation and step 8 explanation, user chose to pause and resume in next session: "Let's pause here". Session was long, step 8 deserves its own focused start, lots of architectural ground covered to settle on.

Documentation updates:

Updated app/plan.md ## Current Status section: replaced 2026-04-17 status with detailed Phase 1 Part 2 shipped/pending checklist, listed every engine + Lua addition, documented model layer + canvas-local coords + workspace drop routing as locked architectural decisions.
Updated app/docs/ui_architecture.md TL;DR to reflect that model–view separation and multi-view are shipped (step 7), canvas-local coords are shipped (7b), and embedded-element host is the next step (8). Added notes about workspace owning drop routing, selection-by-reference, and global undo.

Files added/modified this session:

Engine: Anchor2/engine/src/anchor.c (drop events, cursor API, focus-clickthrough hint, stencil clear, ~150 lines added)
Engine binary: rebuilt and copied to Anchor2/app/anchor.exe and Anchor2/arena/anchor.exe
New: Anchor2/app/content_store.lua, Anchor2/app/undo.lua, Anchor2/app/model.lua, Anchor2/app/panes/canvas.lua
Modified: Anchor2/app/main.lua, Anchor2/app/workspace.lua, Anchor2/app/pane.lua
Modified: Anchor2/app/plan.md, Anchor2/app/docs/ui_architecture.md

Looks good? Approve and I'll write the log, commit, and push.

Yes.

Bash (python E:/a327ex/Anchor2/scripts/find-recent-session.py --limit 5)

Exit code 1
2026-05-11T02:53:59.126Z 674f1db4-782b-4b6c-9449-e48ce4ed9059 [claude] <-- MOST RECENT
   C:\Users\adn\.claude\projects\E--a327ex\674f1db4-782b-4b6c-9449-e48ce4ed9059.jsonl

2026-05-11T02:53:18.610Z b1cbeb96-7ab5-4881-bb7f-ec249ecfa0c8 [claude]
   C:\Users\adn\.claude\projects\E--a327ex\b1cbeb96-7ab5-4881-bb7f-ec249ecfa0c8.jsonl

2026-05-11T01:40:23.351Z 84d9325f-cfc5-4ce3-902a-6feea142e3ba [claude]
Traceback (most recent call last):
  File "E:\a327ex\Anchor2\scripts\find-recent-session.py", line 205, in <module>
  File "E:\a327ex\Anchor2\scripts\find-recent-session.py", line 200, in main
  File "C:\Users\adn\AppData\Local\Programs\Python\Python314\Lib\encodings\cp1252.py", line 19, in encode
UnicodeEncodeError: 'charmap' codec can't encode character '\U0001f986' in position 11: character maps to <undefined>

Bash (date "+%Y-%m-%d %H:%M:%S")

2026-05-10 23:54:31

Anchor App Phase 1 Part 2

Summary

Design that survives going to server

Implementation plan (one slice at a time)

What SDL2 actually sees on Windows

What I'd suggest

What's actually happening

Three honest options

My recommendation

Sub-step 3: Selection + drag-to-move + persistence

Two open design questions

Sub-step 3c: Persistence

State of play

Three honest paths forward

High-level phase overview (from plan.md)

The bug in the current design

The right design

What needs to change

Two ways forward

What we have now

What step 8 adds

Why that's different

Concrete example matching your goal

What changed since step 7

End Session Workflow

Step 1: Get Session Info

Step 2: Write Summary

Step 3: Get User Approval

Step 4: Convert Transcript and Write the Log File

Step 5: Commit Project Repo

Step 6: Push the Repos

Step 7: Confirm

Notes

Anchor App Phase 1 Part 2

Summary

High-level phase overview (from `plan.md`)