| Summary: | Visible banding with gradient map filter, even on high bit depth canvas | ||
|---|---|---|---|
| Product: | [Applications] krita | Reporter: | Kampidh <qampidh> |
| Component: | Filter Layers | Assignee: | Krita Bugs <krita-bugs-null> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | halla |
| Priority: | NOR | ||
| Version: | 5.1.4 | ||
| Target Milestone: | --- | ||
| Platform: | Microsoft Windows | ||
| OS: | Microsoft Windows | ||
| Latest Commit: | https://invent.kde.org/graphics/krita/commit/58794306157146e0a40658554569d0f44d11db26 | Version Fixed In: | |
| Attachments: |
Visible banding on gradient after the filter is applied
Original gradient before the filter is applied Example krita document |
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Created attachment 154878 [details]
Original gradient before the filter is applied
Created attachment 154879 [details]
Example krita document
Try to toggle the Gradient Map filter layer on and off, then observe the gradient.
Thank you for the report. I can confirm the issue. A possibly relevant merge request was started @ https://invent.kde.org/graphics/krita/-/merge_requests/1698 Git commit b9e615b1ff944c86b160232d9563570b511de3d1 by Merge Service, on behalf of Deif Lou. Committed on 05/01/2023 at 07:01. Pushed by merge-service into branch 'master'. Fix issue with banding in the gradient map filter Part-of: <https://invent.kde.org/graphics/krita/-/merge_requests/1698> M +16 -0 libs/pigment/KoColorSpace.h M +17 -1 libs/pigment/KoColorSpaceAbstract.h M +41 -0 plugins/color/lcms2engine/LcmsColorSpace.h M +12 -1 plugins/color/lcms2engine/colorspaces/rgb_u8/RgbU8ColorSpace.cpp M +1 -0 plugins/color/lcms2engine/colorspaces/rgb_u8/RgbU8ColorSpace.h M +6 -6 plugins/filters/gradientmap/KisGradientMapFilter.cpp https://invent.kde.org/graphics/krita/commit/b9e615b1ff944c86b160232d9563570b511de3d1 Git commit 58794306157146e0a40658554569d0f44d11db26 by Halla Rempt, on behalf of Deif Lou. Committed on 05/01/2023 at 09:04. Pushed by rempt into branch 'krita/5.1'. Fix issue with banding in the gradient map filter Part-of: <https://invent.kde.org/graphics/krita/-/merge_requests/1698> (cherry picked from commit b9e615b1ff944c86b160232d9563570b511de3d1) M +16 -0 libs/pigment/KoColorSpace.h M +17 -1 libs/pigment/KoColorSpaceAbstract.h M +41 -0 plugins/color/lcms2engine/LcmsColorSpace.h M +12 -1 plugins/color/lcms2engine/colorspaces/rgb_u8/RgbU8ColorSpace.cpp M +1 -0 plugins/color/lcms2engine/colorspaces/rgb_u8/RgbU8ColorSpace.h M +6 -6 plugins/filters/gradientmap/KisGradientMapFilter.cpp https://invent.kde.org/graphics/krita/commit/58794306157146e0a40658554569d0f44d11db26 |
Created attachment 154877 [details] Visible banding on gradient after the filter is applied SUMMARY Using Gradient Map filter (either from Filter > Map, or Filter Layer) produces a visible banding, even on a higher bit depth canvas (16bpc). Segment and Stop gradient produces the same result. STEPS TO REPRODUCE 1. Create new document, preferably at 16bpc 2. Create a simple gradient (eg. Black -> White) 3. Add Gradient Map with a same gradient as before OBSERVED RESULT Visible banding occurred on the gradient (attached image) EXPECTED RESULT Gradient should be smooth, or at least as smooth as the original layer. SOFTWARE/OS VERSIONS Windows: 10 Pro 21H2 Qt Version: 5.12 ADDITIONAL INFORMATION It seems like the Gradient Map filter is processed with 8-bit precision regardless of the canvas bit depth. This can be observed by picking up the color on the gradient. The original gradient have a smooth transition, while the filtered one will have a bigger steps.