SUMMARY Color gradient at canvas becomes color banding and stair-stepping-like when output format is set to Rec. 2020 PQ (10 bit) and Canvas Graphic Acceleration is enabled. When the color gradient is export to png file and viewed at other software, it retains smooth which it is supposed to be. Turning off Canvas Graphic Acceleration when Rec. 2020 PQ (10 bit) is on would make color gradient smooth, but it is slow and raises some rendering flaws. STEPS TO REPRODUCE 1. At Display-HDR settings-Preferred Output Format, chose Rec. 2020 PQ (10 bit). 2. Reboot Krita. 3. Create a new file. (color depth and icc profile keep default) 4. Paint some color gradient on canvas. OBSERVED RESULT Color banding and stair-stepping EXPECTED RESULT Color gradient should be smooth. SOFTWARE/OS VERSIONS Windows 10 ADDITIONAL INFORMATION GPU: It can be reproduced on my nvidia 1650, 3050 laptop and amd integated GPU on 5800U, with latest driver. Screen: It can be reproduced on my HDR400 capable screen and normal 8bit laptop screen. I have tried changing file color depth and icc profile, but banding still reproduced.
Created attachment 143679 [details] Screenshot: color banding at canvas
Created attachment 143680 [details] The gradient png file used in the screenshot, which is the gradient supposed to look like
Hi, this should be fixed with Krita 5.0, as we made the gradients wide-gamut and high-bit depth aware. Can you try to see if it's still happening?
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Sorry for late reply. I repeated the same test at krita 5.0.2 with the same configuration and gradient file, but color banding still exists, as attachment 3 [details] shows.
Created attachment 145831 [details] Color banding screenshot at krita 5.0.2
(In reply to 2376112839 from comment #5) > Sorry for late reply. I repeated the same test at krita 5.0.2 with the same > configuration and gradient file, but color banding still exists, as > attachment 3 [details] shows. It is attachment 145831 [details]
Please don't change the version field. It should indicate the first version the bug was reported on.
The merge request https://invent.kde.org/graphics/krita/-/merge_requests/1327 may unintentionally fix this bug, but I do not have the hardware to confirm.
A possibly relevant merge request was started @ https://invent.kde.org/graphics/krita/-/merge_requests/1336
Git commit 782fc72d7aa66656db6a1c28c983025a9b5e17e1 by Alvin Wong. Committed on 16/02/2022 at 10:50. Pushed by alvinwong into branch 'master'. Fix banding when rendering canvas in HDR mode Set the proper 16-bit RGBA texture format for the canvas FBO when HDR rendering mode is active. M +7 -1 libs/ui/opengl/KisOpenGLCanvasRenderer.cpp https://invent.kde.org/graphics/krita/commit/782fc72d7aa66656db6a1c28c983025a9b5e17e1
Git commit 2d730ebdb7c91d463836f0767a130eed6bb1609f by Alvin Wong. Committed on 16/02/2022 at 11:02. Pushed by alvinwong into branch 'krita/5.0'. Fix banding when rendering canvas in HDR mode Set the proper 16-bit RGBA texture format for the canvas FBO when HDR rendering mode is active. (cherry picked from commit 782fc72d7aa66656db6a1c28c983025a9b5e17e1) M +7 -1 libs/ui/opengl/kis_opengl_canvas2.cpp https://invent.kde.org/graphics/krita/commit/2d730ebdb7c91d463836f0767a130eed6bb1609f