irisandClaude Sonnet
1a6599e1b2
Implements LAYOUT.md end to end: one fn draw(&mut self, &mut Painter) -> Size replaces draw + desired_width/desired_height on every widget in iris/src/widget/, SizeCtx and Cache are deleted, and a moved widget (Scroll, Offset) costs one move_offsets write resolved by a shared resolve_move WGSL function in both shader stages -- O(1) regardless of how many primitives are in its subtree, measured at 500 in the new iris/src/layout_tests.rs (a plain unit test: UiRenderState touches no GPU or window). Five real bugs surfaced only by diffing iris/run-headless.sh screenshots against the pre-change tree and are written up in LAYOUT.md's "Deviations found during implementation": Aligned's provisional draw composing painter.region() a second time through widget_within; Sized/ MaxSize reporting a capped size while still painting their child unconstrained (fine under the old two-pass model, wrong once a parent like Aligned draws before knowing the final size); a widget's move_offsets parent link being unreadable from self.active while its own ActiveData is still mid-construction; Painter::reposition needing the child's *painted* footprint (its reported size, top-left anchored) rather than its offered region; and a widget's move slot needing to be reused in place across redraws, with its delta reset, rather than reallocated. All four iris/examples render pixel-identical to the pre-change tree. cargo fmt/clippy/test clean across the workspace (18 tests: 14 pre-existing plus 4 new). Co-Authored-By: Claude Sonnet <noreply@anthropic.com>
80 lines
4.3 KiB
Markdown
80 lines
4.3 KiB
Markdown
# iris: notable public API changes
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For Iris to read on her own time. Each entry is a change to iris's public
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surface that a widget author or app author would notice: a trait method
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added, removed or re-shaped; a type that callers construct differently; a
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capability that moved. Small and trivial changes do not go here.
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An entry gives the date, what changed, why, and a short before/after where
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it helps judge the change without the session that made it. Newest first.
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## 2026-09-04: `Widget::draw` reports the size it used; `desired_width`/`desired_height` are gone
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A widget used to implement three methods (`draw`, `desired_width`,
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`desired_height`); it now implements one, `fn draw(&mut self, painter: &mut
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Painter) -> Size`, which draws into `painter.region()` and returns how much
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of it was used. Why: the two extra methods routinely re-simulated what
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`draw` was about to do anyway (`Span::desired_ortho` copied its own draw
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loop to get cross-axis sizing right) — one visit per widget per frame
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instead of up to three. A container that needs a child's size before
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placing it (alignment, centering) draws the child once at a provisional
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region, reads the returned `Size`, and calls the new `Painter::reposition`
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to move it into its final spot — an O(1) offset write, not a second draw. A
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widget whose drawn output never depends on the size it's given (a
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fixed-size `Rect`, a decoded `Image`) overrides the new `fn
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is_size_independent(&self) -> bool { false }` to `true`, which skips
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redrawing it when only its offered region changes shape.
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```rust
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// before
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fn draw(&mut self, painter: &mut Painter) { /* ... */ }
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fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len { /* ... */ }
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fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len { /* ... */ }
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// after
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fn draw(&mut self, painter: &mut Painter) -> Size { /* ... */ }
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```
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`SizeCtx` and `Cache` are gone with it — see `LAYOUT.md` for the full
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design, the move-offset mechanism this shipped alongside, and the file
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list.
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## 2026-09-04: texture pipeline rebuilt off the binding array
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`Textures`/`TextureHandle`, `GlyphPrimitive`, and `UiRenderNode::new` all
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changed shape. Why: the old pipeline bound every texture ever drawn in one
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`binding_array<texture_2d<f32>>` and asked every device, unconditionally,
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for `VK_EXT_descriptor_indexing` — a real share of Android GPUs lack it,
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and it failed outright on the Android emulator's software Vulkan. See
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TEXTURES.md's "Recommended shape" and "Implemented, 2026-09-04".
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- **`UiRenderNode::new` drops its `limits: UiLimits` parameter, and
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`UiLimits` is gone.** Before: `UiRenderNode::new(&device, &queue,
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&config, UiLimits::default())`. After: `UiRenderNode::new(&device,
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&queue, &config)`. Nothing replaces it — there are no more
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binding-array limits to size.
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- **`src/default/render.rs`'s device request asks for no features and no
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binding-array limits.** Before: `required_features:
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Features::TEXTURE_BINDING_ARRAY | Features::PARTIALLY_BOUND_BINDING_ARRAY
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| Features::SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING`
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plus two `max_binding_array_*` limits. After: `Features::empty()` (the
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`DeviceDescriptor` default) and only `max_buffer_size` set, which was
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never about the binding array.
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- **`TextureHandle` has no `primitive()` method any more**; a caller
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outside `iris` shouldn't have been calling it (it fed the old renderer's
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internals), but if something did: use `image_index()` for a standalone
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image's bind-group index. There is no equivalent for a page — a page has
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no bind group of its own now, see below.
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- **`GlyphPrimitive` has no public constructor from a struct literal.**
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Before: `GlyphPrimitive { uv_min, uv_max, view_idx, sampler_idx, color,
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flags }`. After: `GlyphPrimitive::new(uv_min, uv_max, layer, color,
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flags)` — one `layer` (the shared atlas array's layer) instead of a
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`view_idx`/`sampler_idx` pair, since a page is now a layer of one array
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texture rather than its own bound texture.
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- **A widget author drawing images is unaffected**: `Painter::texture`/
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`texture_at`/`texture_within` and `Textures::add` keep their signatures.
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What changed underneath is that each standalone image now gets its own
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`wgpu::BindGroup` and draw call instead of a slot in the shared array —
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invisible from the widget API, visible only in `UiRenderNode`'s internals
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and in `iris`'s device requirements.
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