Codex Step 3 stop-hook flagged: "web repaint ignores actual
canvas size". The prior fix `9cf0f865` hardcoded `960.0` to
match the smoke HTML's `<canvas id="op" width="960">`, but
that's brittle — any host that mounts onto a differently-sized
canvas (responsive HTML, programmatic mount, future smoke
fixture changes) gets the wrong layout viewport.
Fix: WebBackend gains `canvas_width(&self) -> u32` +
`canvas_height(&self) -> u32` accessors. The `width` /
`height` fields are already refreshed at construction
(`canvas.width()`) and on `RenderBackend::resize`, so reading
them per-paint reflects whatever the host's `<canvas>` width
attribute currently is.
`paint_inspector` now:
- Reads `viewport_w` + `viewport_h` from the backend at the
start of each frame.
- Uses them for the white-background clear AND for the
WidgetHost::paint viewport_width arg.
This also resolves the prior "web smoke paints only the
toolbar" issue since the smoke canvas is 960×640 — the first
frame still receives 960 as viewport_width, but now via the
backend instead of a hardcode.
Verification:
- `cargo build -p openpencil-shell-web --target
wasm32-unknown-unknown --features skia --release` — green
- `wasm-bindgen --target web` — produces ../pkg/*
- `bash tools/check-wasm-bundle.sh` — PASS, 0 env.*, 907 031
bytes gzip = 86% of 1 MiB ceiling (negligible delta — two
small accessor methods).
7e1fbcabf0