v0.25.2

Experimental web-canvas backend — feature = "web-canvas" runs mirui in wasm32-unknown-unknown against an HTML <canvas> 2D context. App::tick is driven from requestAnimationFrame, DOM pointer / wheel / touch / keyboard events are bridged into the input queue, and texture uploads are cached per-canvas through OffscreenCanvas.

Added

• feature = "web-canvas" — opt-in browser backend on web-sys 0.3.99, js-sys 0.3.99, wasm-bindgen 0.2.122, wasm-bindgen-futures 0.4.72, and web-time 1.
  • mirui::surface::web_canvas::WebCanvasSurface wraps a DOM <canvas>, sizes the backing store to logical × devicePixelRatio (fractional DPR preserved), captures the pointer on pointerdown so drags survive crossing the canvas edge, and unregisters every DOM listener through Drop.
  • mirui::draw::web_canvas::WebCanvasRendererFactory paints fills / strokes / blits / text via Canvas 2D. Quad blit subdivides the source rect into an 8 × 8 affine triangle mesh — Canvas 2D has no homography, so subdivision approximates the projective warp.
  • Runner::start_animation_frame() (under cfg(target_arch = "wasm32", feature = "web-canvas")) drives the run-loop from requestAnimationFrame and returns to the wasm-bindgen entry so the browser keeps owning frames.
• gallery-web crate — ?demo=<name> query parameter selects which gallery::demos::*::build runs (dsl is the default).
• gallery::demos::* — demo bodies hoisted out of examples/ so the same build(setup) feeds both the native cargo examples and the wasm crate.
• xtask wasm-check — cargo check --target wasm32-unknown-unknown --no-default-features --features web-canvas --lib. Skips silently when the rustup target is missing.
• xtask wasm-build — release build of gallery-web plus a wasm-bindgen --target web post-process into gallery/web/pkg/.

Changed

• web_time::Instant replaces std::time::Instant in StdInstantClockPlugin and the perf path. Native re-exports std::time; wasm32 reads performance.now().

Limitations

• Effect widgets that read or modify the framebuffer — BackgroundBlur, MirrorOf, TemporalMix — are unimplemented on Canvas 2D. gallery-web does not route the effect demo.
• RGB565 / RGB565Swapped textures fall through to a no-op blit.
• A non-trivial 2D WidgetTransform outside a quad path is multiplied as dpr × widget_tf once per command. Quad branches paint under a DPR-only matrix because the four points already encode every parent transform.