Rework of the review on #11. Pages and standalone images were one
`Textures` manager separated by a `TextureKind` tag, and images were a
second instance list beside `Primitives::instances`. The tag forced
`image_index()`/`layer()` to panic on the wrong kind of handle, and the
second list forced an `is_image` branch through `free`, `region_mut`,
`apply_free` and `PrimitiveChange`.
Pages are now their own thing. `GlyphAtlas` owns its page images
outright and hands the renderer dirty rectangles; `GpuPages` owns the
array texture they upload to. `Textures` is standalone images only, so
`TextureHandle` has one kind, `slot()` cannot be wrong, and nothing
needs a free list that skips pages. `GlyphAtlas::insert` no longer takes
a `Textures`, which drops that parameter from `TextData::render` and
`SizeCtx` too.
Images go back through the one instance list. A texture instance is an
ordinary `PrimitiveInstance` whose `idx` names a texture rather than a
group-1 entry, which `PrimitiveHandle::data_idx: Option` records.
`RenderLayer::plan_draws` batches the layer's instances into runs
sharing a bind group, so a ui with no images still plans a single draw,
and an image draws in instance order rather than on top of its layer.
Group 2 is now one `texture_2d_array` and a sampler, bound per run: the
atlas for rects and glyphs, or one image viewed as an array of one. That
removes the second texture binding and the 1x1 null view that had to
fill it. Masks move to group 3, so resizing that buffer no longer stales
every texture bind group, and `GpuTextures` no longer reports whether
the caller must rebuild one.
`GlyphPrimitive` drops its manual pad: the WGSL struct now declares the
uvs as scalars, which matches the Rust layout exactly. `#[repr(C,
align(8))]` would have left real padding bytes, which `bytemuck::Pod`
forbids.
Verified with a headless run of the `tabs` example and of a scratch
example mixing images, rects, glyphs and a mask in one layer; 52 glyphs
at size 300 grew the atlas array from 1 to 4 layers with every earlier
page still sampling correctly.
Replace the cosmic-text path with Parley layout and Swash rasterization, backed by shared glyph-atlas pages. Shaping, editing, rasterization, and glyph rendering move together because they share the text buffer and rendered-glyph types; splitting them further would require a temporary renderer that is immediately removed.
This is reconstructed rather than replayed from the extraction history. It also fixes issues found during review:
- texture binding changes remain set when an atlas patch follows a new page
- pressing an empty field places a caret and accepts input
- selection motion delegates collapse behavior to Parley
- character deletion follows logical clusters rather than visual neighbors
- the unused root-level Swash dependency is omitted
Four public-behavior integration tests live in `tests/text_edit.rs`: empty-field input, multibyte IME preedit replacement, UTF-8-safe backspace, and selection replacement. The old twelve-test inline block and implementation-restating cases are omitted.
Every added source comment was manually reviewed. Comments that narrated implementation or history were removed; retained comments document cache/rasterization keys, GPU upload constraints, focus representation, bidi geometry, or IME semantics.
Known limitation: atlas pages currently grow without eviction. Each page is 4 MiB on CPU and GPU. An arbitrary cap would leave cached rendered-text UVs pointing at reused glyph slots, so bounding this safely needs a later generation/invalidation change.
This changes public text types and signatures. GPU glyph rendering is covered by compilation rather than a live-surface test.
Verified with:
- `cargo fmt --all --check`
- `cargo clippy --workspace --all-targets -- -D warnings`
- `cargo test --workspace` (four integration tests pass)
Cargo still reports inherited future-incompatibility notices for existing wgpu/winit dependencies; there are no current clippy warnings.
---------
Co-authored-by: iris <2+iris@noreply.localhost>
Reviewed-on: iris/iris#10
Reviewed-by: iris <2+iris@noreply.localhost>
Co-authored-by: AIris <4+iris-ai@noreply.localhost>
iris
iris-aiandiris