Fixes #5502 - Shadows now overlay raster ImageView (Sixel & Kitty)#5506
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Blank cells carrying an opaque background (e.g. a View's shadow) drawn over a raster image were suppressed along with the image's own transparent cells, so shadows vanished over Sixel/Kitty images. OutputBase now treats only transparent (alpha-0) blank cells as raster-owned; opaque blanks are emitted so they paint over the image (Sixel) or appear above the z=-1 placement (Kitty). ImageView marks its raster-covered cells transparent so image-owned cells stay suppressed while later opaque overlays show through. Adds failing-first OutputBase tests for the Sixel and Kitty paths. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This was referenced Jun 22, 2026
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Fixes
Follow-up to #5493. Addresses the one outstanding review item from that PR — @YourRobotOverlord's approving-review nit: "shadows do not overlay the image" (reproduces on both Sixel and Kitty). All of the automated reviewer comments on #5493 were already resolved before merge (re-audit in #5502).
Root cause
Raster images are composited by the terminal on top of the text-cell grid. To let the image show through,
OutputBaseskips emitting blank cells that fall within a raster image'sDestinationCells— but the check (IsRasterCoveredBlankCell→IsBlankCell) was grapheme-only, so it also dropped a shadow cell (a blank space carrying an opaque dimmed background). The shadow therefore vanished over the image.Fix
OutputBase— newIsRasterOwnedBlankCell: a blank cell is raster-owned (and suppressed / cleared-through) only when its background is transparent (Background.A == 0). An opaque blank (a shadow, a colored fill) is intended overlay content and is emitted so it paints over the image (Sixel) or appears above thez=-1placement (Kitty). Used by both the main-loop suppression andClearKittyRasterBlankCells.ImageView— marks its raster-covered cells transparent (Color.None) so image-owned cells stay suppressed while later opaque overlays show through.The behaviour is symmetric across Sixel and Kitty (Kitty images are already placed at
z=-1, below the text layer).Tests
OutputBaseTests(Write_SixelRasterImage_EmitsOpaqueBlankOverlayCell_SoShadowsOverlayImage,Write_KittyRasterImage_…) — red before the fix, green after.Visual verification
Reconstructed from the app's real terminal output (Kitty graphics placement at
z=-1composited under the ANSI cell layer). Two identical shadow-casting boxes — one over a raster image, one over the window background (control). Before: the over-image shadow vanishes. After: it matches the control.🤖 Generated with Claude Code