RUST.md gets the report verbatim with what each of the four defects
actually was, the tests that pin them, and two traps worth not
re-finding (a fixed-coordinate tap that "failed" by 544px because it had
toggled a tool group, and a layer-1 repro that only reproduces inside a
`List`). IRIS.md and DECISIONS.md get the design half: one `Flinger`
whose seam puts the sign convention and the content's end with the
caller, a cancel as a first-class end to a gesture, and why a row is
drawn twice on the frame its height changes.
LAYOUT.md gains the two rules those turned on, since both govern the
layout rather than this pass: padding works in any container and is an
inset or an outset depending on how tight the parent's region is (Iris's
own words), and a widget offered a box it does not fit is drawn again at
its true box in the same frame rather than the next one.
IRIS_TODO.md's "worked around in tool.rs rather than fixed here" is gone
-- Iris, 2026-09-08: "There should never be workaround code." Two of the
four entries are ticked; the two that remain are missing capabilities
rather than defects being dodged, and each now carries a diagnosis of
what building it costs instead of a workaround: an overflow ellipsis
needs `TextBuffer` to have a displayed string distinct from its source
(parley has none of its own, and every byte-offset consumer -- spans,
`byte_at`, `Selection`, `apply_delta` -- moves if the buffer is
truncated), and selectable tool-card text needs a register/unregister
lifecycle across the three routes that rebuild a card, which is where a
stale `Selection` handle panics.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Iris, on the code fence: "the code block scrolling currently masks in an
inner rectangle. Ideally masks should have a shape associated with them,
rounded rectangle being one of them ... so that the mask becomes the
parent container with rounded edges. Make sure alpha works properly with
it, eg. on the corners where alpha should be decreased / multiplied."
`Mask` is now `{ primitive, parent }` -- the slot of a primitive already
written, plus the mask this one nests inside. The fragment stage
evaluates that primitive's own coverage at the masked pixel, through the
same `rounded_rect_coverage` a drawn rect goes through, and multiplies it
into the alpha along the whole `parent` chain. Nothing about the shape is
copied, so a rounded container's corner and its children's clipped corner
are one piece of arithmetic and cannot drift; two nested feathers dim a
pixel twice, which is the multiply she asked for.
`.masked()` is unchanged for callers: it writes an undrawn rect
(`Drawn::No`/`NOT_DRAWN` -- owned, moved, resized and freed like any
other primitive, simply never rasterized) and points at that, so square
clipping is the same mechanism rather than a special case. New
`.masked_by(shape)` draws `shape` behind the content in its own layer and
clips to the first primitive it drew, with no radius written twice; it
replaces `.masked().background(w)`, which drew both and clipped to the
box. `transcript-ui`'s `BlockFrame::Verbatim` is the first caller.
Hit-testing applies the shape (`SensorUi::run_sensors` ->
`UiRenderState::mask_admits`, coverage above one half, which is where the
drawn edge is), as well as the widget's own box -- the two ask different
questions and both have to hold. `primitive_corners` is a floor-for-floor
transliteration of the shader's `corners_of`, not `region.to_px()`: the
phone's 2.55 density puts nothing on a whole pixel, and skipping the
rounding disagrees with the pixels by up to one along each edge.
A mask's shape must be a rect, asserted by name in `set_mask_to`. A glyph
would need a CPU-side alpha plane before the hit test could agree with
the shader, and a standalone image a bind-group switch the fragment stage
cannot make. So no texture mask exists; the branch where one would go is
in both copies of `mask_coverage`. docs/LAYOUT.md's section end lists this
and the three other places the code is narrower than the design.
Tests. Layer 1, `layout_tests.rs`: the child's coverage swept across the
container's corner arc equals the container's own exactly; nested masks
multiply rather than intersect, asserted where both feathers are partial,
which is the only place the two differ; a press in a rounded-away corner
misses while one inside the curve and one on a straight edge hit; and
`a_plain_mask_still_clips_to_a_square_box`, the half this had no reason to
touch. The first version of the corner test swept the straight chord
between the arc's ends, which lies inside the circle everywhere -- it
proved nothing and said so, which is why it counts both sides now.
`iris/tests/mask_sdf.rs` is the only test here that needs a GPU: it lifts
`distance_from_rect` and `rounded_rect_coverage` out of
`iris_core::SHAPE_SHADER` by name -- lifted, not copied, since a copy
would be edited alongside the shader -- and runs them in a compute pass
over ~200k points at five radii against `iris_core::rounded_rect_coverage`.
Worst disagreement under 1e-5; the negative control (`+ 0.01` inside the
shader's smoothstep) fails it at 0.03.
Layer 2 for looking: `./run-headless.sh phone --phone --shot /tmp/mask.png
--seconds 6 -- -p transcript-fixture` draws the fixture's horizontally
scrolled code fence clipped on the curve at both top corners.
Two things found on the way and fixed here:
- The winit backend had the defect the Android one was fixed for in
85869d0 -- `Backends::PRIMARY` and an `.expect` on the adapter. This
VM's Venus device disappears when the host runs out of virgl contexts,
which happened mid-task, and layer 2 aborted with `Could not get
adapter!` while GL sat there working. It probes and rebuilds the
instance on `Backends::GL` exactly as Android does now, and the request
names the backends it tried. The rule had been written on one member of
a set of two.
- `active_primitive_count` counted mask shapes, so `iris::frame`'s
`primitives=` -- a number Iris reads off a phone report as "how much is
on screen" -- would have gained one per masked widget.
`widget_trait!` now accepts a `///` doc comment on its functions, since
`masked_by` is public API and rustdoc is where a contract is read.
docs/LAYOUT.md, docs/RUST.md (both queue boxes, the commands, and where
the GPU test sits among the three layers), docs/IRIS.md and
docs/IRIS_TODO.md ("Masks defined relative to each other", now closed).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Iris: masks should carry a shape, rounded rectangle first, or take a
container widget as the mask, with corner alpha multiplied rather than
cut. Design: the mask evaluates the same SDF draw_rounded_rect uses,
nested masks chain and multiply like moves, and a rounded Rect's
.masked() makes the container the mask with one radius by construction.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
docs/IRIS.md's 2026-09-06 entry (public API), docs/LAYOUT.md's "Density:
Len::dp" design section, IRIS_TODO.md's density-unit item ticked, and
docs/RUST.md's P0 box gets the investigation: the keyboard-wipe
hypothesis and confirmation, the blur root cause and why the dp unit
turned out to be the same fix, the header cause, and what remains
unverified (an emulator screenshot of the keyboard fix, and Iris's real
phone).
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
irisandClaude Opus 5