Nothing here is film simulation. These are lints that fail master today,
under the -D warnings CI runs with, mostly from a toolchain that learned
new ones rather than from anybody's code -- `is_multiple_of` and the
derivable `Default` did not exist as lints when this was written.
They are fixed rather than allowed, and by hand rather than by trusting
`cargo clippy --fix` wholesale: its automatic pass split a derive in two
and left a stray blank line, which is the sort of thing that is correct
and still wrong to commit.
The four that needed a decision rather than a rewrite:
- The distance transform's inner loop writes through its iterator now.
`q` stays, because it is the position the parabola is evaluated at as
well as the index it is written to -- the lint is about the write.
- `to_source` and `to_proto` take `self` by value. Their receiver is
`Copy`, so this is the same machine code and the honest signature.
- The export path's return type is five levels deep and now has a name,
plus a line saying why the `Option` wraps the `Result`: `None` is
cancellation, which is not a failure and has no error to report.
- A test fills a range instead of looping over one.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
`cargo fmt --check` is a required step and had drifted across 45 files. Most of
it arrived this week: several operations were written in parallel worktrees and
merged by hand, and a hand-merge resolves conflicts without ever running the
formatter over the result.
No behaviour changes — this is `cargo fmt --all` and nothing else, kept as its
own commit so the next reader can skip it wholesale rather than search it for
one that matters.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Feathering, growing, shrinking, closing and opening are the same number
read differently. With the signed distance from the boundary in hand,
dilation is the set where d >= -r, erosion where d >= +r, and a feather of
any shape is a function of d. So the field is computed once and the
controls are arithmetic on it.
The **field** is what reaches the GPU, not a finished alpha, and that is
the point: growing a mask or changing its falloff then costs a uniform
upload and no recomputation, which is what makes them live controls rather
than ones that stall on every drag. Only closing and opening rebuild,
because after the first threshold the shape has changed and the old
distances describe the old one.
Exact Euclidean, via Felzenszwalb's separable transform — not a chamfer
approximation, which leaves a mask visibly octagonal once grown more than
a few pixels. A test asserts the diagonal is √2 rather than 1 or 2.
It runs on the CPU, which ARCH §5.4 forbids for masks. The rule is about
brush lag — a stroke rasterised per frame — and this is a different
operation: once per mask edit, on input the model already produced here,
producing a field the GPU then samples for free. What it buys is exact
determinism, which matters because masks reach the sidecar as indices and a
field that varied by vendor would mean a mask meaning one thing on the
desktop and another on the phone.
The half-pixel in `signed_distance` is not a detail, and a test caught it.
Measuring to the nearest opposite pixel *centre* puts the smallest
magnitude at 1 either side, so the boundary is nowhere and **eroding by
less than a pixel removes nothing**. A control whose first notch does
nothing is a broken control. Half a pixel off each side puts the boundary
where it physically is, and eroding by 1 takes exactly the outermost ring.
Every falloff curve is 0.5 at the boundary by construction, asserted for
all five: changing the curve should change how the transition looks and
never where it sits.
dtourolleandClaude Opus 5