fix(canvas): give the overlay the monitor profile on the GPU path - #1200
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marcinz606 merged 2 commits intoSep 27, 2026
Merged
marcinz606 merged 2 commits into
marcinz606 merged 2 commits into
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On the GPU path the canvas passed the monitor ICC to the shader's display LUT but not to the overlay, so the overlay's host-side images (the before/after baseline, the test strip mosaic) were converted for an sRGB display. On a wide-gamut monitor the Before half of the split read as more saturated than the After half on every frame. The overlay's image caches are now also keyed on the monitor profile, so a screen change rebuilds them.
The notes sheet is saved as an untagged JPEG, which viewers read as sRGB, but it was built from the canvas's display image, which is in the monitor's color space. On a wide-gamut monitor the saved sheet came out oversaturated. The CPU path always did this; giving the overlay the monitor profile on the GPU path extended it there.
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On a wide-gamut display, the Before half of the before/after split always looked more saturated than the After half. On the GPU path the canvas passed the monitor ICC profile to the shader's display LUT but not to the overlay, so everything the overlay converts on the host (the before/after baseline, the test strip mosaic, the loupe image) was converted for an sRGB display while the frame itself was converted for the monitor.
The overlay now gets the same monitor profile as the shader, and its image caches are keyed on it so a screen change rebuilds them. The printing notes sheet, which is saved as an untagged JPEG, is now converted for sRGB rather than for the monitor; the CPU path always wrote it in monitor space, and this change would otherwise have extended that to the GPU path.