SetSize took its declared length out of UiRegion::FULL, which is the box
it was already given, so a span that had sized that box from the same
hint had the fraction taken twice: .width(rel(0.5)) in a 400-wide span
drew its child 100 wide. It held under a Pad or the root, which do not
honour a hint, and hid under px, where 200 of a 200-wide box is all of
it. The text example was 111,923 pixels from upstream/main because of
it.
Whoever draws a widget now takes its declared length, in its own box,
which is what a fraction of one means, and is the identity for a caller
that already reserved the space. rest is not taken: a share of what is
left over is only a length to the widget dividing one, so it passes up
in the size as it does out of a span. SetSize keeps only what it
declares.
A declared length is then part of the box its parent decided, so
changing one has to redraw the parent; the lengths resolved into a box
are kept beside it and compared. Assuming instead that any dirty widget
which declares a length needs its parent costs 17% of a frame that
dirties 130 of 260 widgets, and buys nothing.
All five reference renders, the resize render and the image replay are
byte-identical to upstream/main, the 100-seed sweep passes, and the
resize fixture is 1.286 ms against 1.289 before.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
iris-aiandClaude Opus 5
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