As is typical with Wayland, the protocol is poorly designed and
implemented even worse. Hyprland 0.53 has completely broken color
management.
https://github.com/hyprwm/Hyprland/discussions/12788
In addition it and mangowc crash when using color management with nouveau drivers.
https://github.com/kovidgoyal/kitty/issues/9030
KDE kwin does not support the sRGB transfer function. And the geniuses
at Wayland are any way planning to deprecate sRGB as a transfer function.
Only GNOME mutter seems to get it right.
Then there are people that are likely going to shoehorn this into EGL
instead of leaving it under application control via the protocol anyway.
https://github.com/KhronosGroup/EGL-Registry/issues/197
Sigh. Wayland.
Implements modern wide gamut color formats with CSS Color Module Level 4
gamut mapping, addressing PR feedback with Go implementation, performance
benchmarks, and reorganized documentation.
Features:
- OKLCH (perceptually uniform color space)
- CIE LAB (device-independent color space)
- CSS Color 4 compliant gamut mapping algorithm
- Inline comment support in color config parsing
Addressing PR Feedback:
1. Go Implementation (tools/utils/style/):
- Complete OKLCH and LAB parsing with gamut mapping
- Matches Python implementation structure
- Comprehensive test suite (all tests passing)
- Performance benchmarks showing acceptable overhead
2. Performance Benchmarks:
- OKLCH: ~4.6 µs/op
- LAB: ~1.5 µs/op
- 10 mixed colors: ~13 µs total
- Typical config (50 colors): <0.5ms startup impact
3. Documentation Reorganization:
- Moved detailed color docs to docs/wide-gamut-colors.rst
- Configuration docs now link to separate documentation
- Reduces size of main configuration documentation
Gamut Mapping:
- Binary search chroma reduction from CSS Color Module Level 4
- Preserves lightness and hue while reducing chroma for out-of-gamut colors
- Uses deltaE OK (JND threshold: 0.02) for perceptual difference
- Ensures graceful degradation on sRGB displays
Python Implementation:
- parse_oklch(): OKLCH color parsing with gamut mapping
- parse_lab(): CIE LAB parsing with gamut mapping via OKLCH conversion
- lab_to_oklch(): LAB to OKLCH conversion for consistent gamut mapping
- oklch_to_srgb_gamut_map(): CSS Color 4 gamut mapping algorithm
- srgb_to_oklab(): Reverse conversion for deltaE calculations
- deltaE_ok(): Perceptual color difference in OKLab space
Go Implementation:
- colorspaces.go: All color space conversions and gamut mapping
- wrapper.go: ParseColor() updated to support OKLCH and LAB
- Comprehensive test coverage with benchmarks
- Matches Python implementation behavior
Robustness:
- NaN and infinity validation in all color parsing functions
- Defense-in-depth with validation at parsing and gamut mapping levels
- Returns None/error for invalid input (consistent error handling)
- Validates before clamping operations to prevent NaN propagation
Files changed:
- Python: kitty/rgb.py, kitty_tests/datatypes.py (+250 lines)
- Go: tools/utils/style/colorspaces.go, wrapper.go (+350 lines, tests)
- Docs: docs/wide-gamut-colors.rst (moved from inline)
- Config: kitty/options/definition.py (simplified, links to docs)
References:
- CSS Color Module Level 4: https://www.w3.org/TR/css-color-4/
- OKLCH Color Space: https://bottosson.github.io/posts/oklab/🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
