painter: add Clipper (PushClip/PopClip) + fix StrokeRect double-corner - #5
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Adds an optional Clipper capability so a scrollable/overflowing widget can confine a child to its bounds — the missing primitive behind toolkit ScrollView overdrawing its neighbours. PushClip(r) intersects r with any enclosing clip; every write (PixelPainter.PutPixel, CellPainter.set/setFg — all primitives funnel through these) is dropped outside the active clip. Non-breaking: it's a separate interface, not a change to Painter; widgets type-assert it. Also fixes PixelPainter.StrokeRect painting its 4 corners twice (the vertical runs now skip the corner rows the horizontal runs already covered) — a translucent border no longer composites the corners darker than the edges. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Two audit findings, both rooted here.
Clip primitive (the architectural gap).
Painterhad no way to confine drawing to a sub-rect, sotoolkit.ScrollView(and any overflowing ListBox/TextView/Table) could only clip at the whole-surface edge and overdrew neighbours. Adds an optionalClipperinterface (PushClip/PopClip) — non-breaking, since it's separate fromPainter; widgets type-assert it.PushClip(r)intersects with any enclosing clip; every write is dropped outside the active clip. BothPixelPainter(viaPutPixel) andCellPainter(viaset/setFg) implement it — all primitives funnel through those, so one guard covers fills, strokes, text, and round-rects.StrokeRect double-corner (Low, latent).
PixelPainter.StrokeRectpainted the four corners twice (horizontal + vertical runs), so a translucent border composited the corners darker than the edges. The vertical runs now skip the corner rows.100% coverage;
go vetclean; 6 arches + wasm build.🤖 Generated with Claude Code