A pragmatic set of modern colour space transforms
Overview
colourspace provides correct, minimal colour space transforms optimised for UI frameworks and creative tooling, covering OKLCh, OKLab, sRGB, Display P3, and Rec. 2020. Transforms are direct matrix multiplications with pre-computed matrices derived with tools/builder.odin. Perceptual manipulation and colour appearance work uses OKLab as the working space.
Gamut mapping is explicitly out of scope. Out-of-gamut values are passed through as-is, and handling is left to the caller — typically shader-side in a display pipeline.
High Dynamic Range (HDR) Support
Rec. 2020 alongside Perceptual Quantizer and Hybrid Log-Gamma transfer functions are kept behind a compile-time flag -define:COLOURSPACE_ENABLE_HDR.
Quick Start
Construct colours in any covered space, convert between them freely, and encode for display. All conversions are hue-preserving and operate in linear light unless explicitly encoded.
package main import "core:fmt" import cs "colourspace" main :: proc() { // Construct colours lch: cs.OKLCh = cs.oklch(0.6456, 0.1003, 71.27) lab: cs.OKLab = cs.oklab(0.6456, 0.0337, 0.0942) srgb: cs.Linear_sRGB = cs.linear_srgb(0.5, 0.3, 0.1) p3: cs.Linear_P3 = cs.linear_p3(0.5, 0.3, 0.1) // OKLab roundtrip linear_from_lch: cs.Linear_sRGB = cs.oklch_to_srgb(lch) lch_from_linear: cs.OKLCh = cs.srgb_to_oklch(linear_from_lch) linear_from_lab: cs.Linear_sRGB = cs.oklab_to_srgb(lab) // Linear roundtrip p3_to_srgb: cs.Linear_sRGB = cs.p3_to_srgb(p3) srgb_to_p3: cs.Linear_P3 = cs.srgb_to_p3(srgb) // Gamma (de)compression decoded: cs.Linear_sRGB = cs.srgb_decode(cs.sRGB{0.5, 0.3, 0.1}) encoded: cs.sRGB = cs.srgb_encode(decoded) fmt.println(linear_from_lch, lch_from_linear, linear_from_lab, p3_to_srgb, srgb_to_p3, decoded, encoded) }
References
Björn Ottosson
- A perceptual color space for image processing
- Two new color spaces for color picking - Okhsv and Okhsl
- sRGB gamut clipping