Add CSS Color 4/5 color functions (oklch/oklab/lab/lch, color-mix)#222
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Add CSS Color 4/5 color functions (oklch/oklab/lab/lch, color-mix)#222jhaygood86 wants to merge 1 commit into
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Add object-model parsing and sRGB resolution for the CSS Color 4/5 color functions oklch(), oklab(), lab(), lch(), and color-mix(), plus the lenient CSS Color 4 space-separated and slash-alpha forms of rgb()/rgba()/hsl()/hsla()/hwb(). - FunctionNames: add Lab, Oklab, Lch, Oklch, ColorMix. - ColorSpaceMath (new): sRGB <-> lab/oklab/lch/oklch/xyz/display-p3/hsl/hwb conversion math plus premultiplied and polar-hue interpolation. Portable Cbrt/Clamp01 helpers so it compiles on net48/netstandard2.0. - Color: FromLab/FromOklab/FromLch/FromOklch factories and a Mix(color-mix) factory. - ColorFunctionExtensions (new): token-stream -> Color resolver (ToResolvedColor / ParseColorFunction), including the percentage-before-color color-mix operand form. - ColorInterpolationMethodGrammar (new): shared in <color-space> <hue>? prelude grammar. - Converters: lenient Any-based Lab/Oklab/Lch/Oklch/ColorMix and space/slash rgb/hsl/hwb converters, appended after the existing strict comma-form converters in ColorConverter so legacy serialization is unchanged. - Tests: ModernColorTests covering parse + resolved sRGB values. Spec: https://www.w3.org/TR/css-color-4/ and css-color-5 (color-mix).
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July 24, 2026 20:09
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jhaygood86
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July 24, 2026 20:37
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Summary
Adds CSS Color 4/5 color functions, resolved to sRGB (CSS Color 4, CSS Color 5):
oklch(),oklab(),lab(),lch()— modern perceptual color spaces.color-mix(in <space>, …)— including the percentage-before-color operand form.rgb()/rgba()/hsl()/hsla()/hwb()— space-separated and slash-alpha (rgb(r g b / a)). This also fixes a latent stack-overflow wherehsl()/hwb()used as solid colors recursed forever.Design
oklch(0.63 0.26 29)round-trips), mirroring ExCSS's existingAspectRatioValueConverteraccept-and-preserve precedent. The strict comma-form converters stay first so legacy serialization (hsla(50deg, …)) is unchanged; lenientAny-based converters are appended.ColorFunctionExtensions.ToResolvedColorover the token stream, backed by a newColorSpaceMath(sRGB↔lab/oklab/lch/oklch/xyz, premultiplied-alpha + polar-hue interpolation).ColorgainsFromLab/FromOklab/FromLch/FromOklchand a color-mixMixoverload.Portability
Builds clean across all 8 target frameworks.
Math.Clamp/Math.Cbrt(absent on net48/netstandard2.0) are replaced with portable helpers; no C# 10+ syntax (LangVersion 9).Tests
ModernColorTests— 43 parse + resolve cases (oklch/oklab/lab/lch, color-mix in a space, space-separated & slash-alpha rgb/hsl/hwb, and the hsl()/hwb()-as-solid-color regression). Full suite green (1559 passing, no regressions).Ported from PeachPDF, which vendors ExCSS.