`try_reuse`'s pure-translation case now writes the widget's move slot
instead of remapping every primitive in its subtree. Counted on a span
of 20 rows, each five primitives deep, when the row above them changes
height:
before 100 primitive region writes
now 0, and 20 slot writes -- one per row the span re-placed
`window_region` walks the same chain on the CPU, so hit testing and
anyone asking in window pixels see a widget where the shader draws it.
`Moves::resolve` stops at `CHAIN_LIMIT` like the shader, and asserts in
debug that it got to the end rather than running out.
Two things fall out of it. Rewriting a region is the one thing a slot
cannot express, so `mov` zeroes the slots of everything it rewrites: a
region is what its slot was a delta from. And `try_reuse` loses its
`old == region` shortcut, which was wrong once a slot exists -- a widget
offered exactly the box it drew against has to have its delta cleared,
not skipped.
`Moves` lives on `UiRenderState` rather than `UiData`, because the draw
is what produces it and `window_region` should not need the ui's
resources to answer where something is. The renderer already takes both.
A slot is retired in `remove_rec`, after the descendants whose slots
name it as their parent. Either order is correct here -- nothing can
claim a freed index while a subtree is coming down, since `on_undraw`
cannot reach the slots -- but this way `remove`'s `undraw` flag only
notifies rather than also deciding slot lifetime, and the retirement
sits beside the recursion it follows.
Checked: fmt, clippy and 41 tests. `tabs` (with the image replay),
`view`, `minimal` and `text` all still render byte-identical, and the
live sway resize round trip -- which re-places most of the tree at the
same size, so it is the slot path throughout -- matches a cold start at
each size.
iris-ai
8223a55cfb