render: placeholder images show a dark band between cell rows #86

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opened 2026-10-09 22:43:17 +09:00 by natsukium · 0 comments

natsukium commented

2026-10-09 22:43:17 +09:00

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An image drawn through Unicode placeholder cells shows a dark horizontal band between every row of cells. The tile maths in placeholder_tile_quad (crates/felis-render-wgpu/src/lib.rs) uses consecutive cut points, so the source slices meet; the band is something drawn over or between the tiles, not yet root-caused.

Seen with a 200×100 test image and virtual placements of 10×10 and similar sizes, in felis windows under a headless sway (output scale 1). The same placement in kitty draws one continuous image. A direct placement (no U=1) of the same image shows no band.

Repro: transmit an image, a=p,U=1,i=1,c=10,r=10, and print the 10×10 block of U+10EEEE cells with the row/column diacritics and the image id in the foreground color.

Next: check whether the band is a row's background or decoration pass painted after the image tiles, or a tile quad shorter than the cell height.

An image drawn through Unicode placeholder cells shows a dark horizontal band between every row of cells. The tile maths in `placeholder_tile_quad` (`crates/felis-render-wgpu/src/lib.rs`) uses consecutive cut points, so the source slices meet; the band is something drawn over or between the tiles, not yet root-caused. Seen with a 200×100 test image and virtual placements of 10×10 and similar sizes, in felis windows under a headless sway (output scale 1). The same placement in kitty draws one continuous image. A direct placement (no `U=1`) of the same image shows no band. **Repro:** transmit an image, `a=p,U=1,i=1,c=10,r=10`, and print the 10×10 block of U+10EEEE cells with the row/column diacritics and the image id in the foreground color. **Next:** check whether the band is a row's background or decoration pass painted after the image tiles, or a tile quad shorter than the cell height.

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2026-10-12 15:18:45 +09:00

natsukium referenced this issue from a commit

2026-10-12 16:30:34 +09:00

render: check that a placeholder image has no band between cell rows

natsukium referenced this issue from a pull request that will close it,

2026-10-12 16:30:38 +09:00

Pin the placeholder image row seam with a GPU test #122

natsukium closed this issue