+++ /dev/null
-"use strict";
-
-// these algorithms are sourced from https://drafts.csswg.org/css-color/#color-conversion-code
-
-function lin_sRGB(RGB) {
- // convert an array of sRGB values in the range 0.0 - 1.0
- // to linear light (un-companded) form.
- // https://en.wikipedia.org/wiki/SRGB
- return RGB.map(function(val) {
- if (val < 0.04045) {
- return val / 12.92;
- }
-
- return Math.pow((val + 0.055) / 1.055, 2.4);
- });
-}
-
-function matrixMultiple3d(matrix, vector) {
- return [
- matrix[0][0] * vector[0] +
- matrix[0][1] * vector[1] +
- matrix[0][2] * vector[2],
- matrix[1][0] * vector[0] +
- matrix[1][1] * vector[1] +
- matrix[1][2] * vector[2],
- matrix[2][0] * vector[0] +
- matrix[2][1] * vector[1] +
- matrix[2][2] * vector[2]
- ];
-}
-
-function srgb2xyz(srgb) {
- return matrixMultiple3d(
- [
- [0.4124564, 0.3575761, 0.1804375],
- [0.2126729, 0.7151522, 0.072175],
- [0.0193339, 0.119192, 0.9503041]
- ],
- srgb
- );
-}
-
-function chromaticAdaptationD65_D50(xyz) {
- return matrixMultiple3d(
- [
- [1.0478112, 0.0228866, -0.050127],
- [0.0295424, 0.9904844, -0.0170491],
- [-0.0092345, 0.0150436, 0.7521316]
- ],
- xyz
- );
-}
-
-function xyz2lab(xyzIn) {
- // Assuming XYZ is relative to D50, convert to CIE Lab
- // from CIE standard, which now defines these as a rational fraction
- const ε = 216 / 24389; // 6^3/29^3
- const κ = 24389 / 27; // 29^3/3^3
- const white = [0.9642, 1.0, 0.8249]; // D50 reference white
-
- // compute xyz, which is XYZ scaled relative to reference white
- const xyz = xyzIn.map((value, i) => value / white[i]);
-
- // now compute f
- const f = xyz.map(
- value => (value > ε ? Math.cbrt(value) : (κ * value + 16) / 116)
- );
-
- return [
- 116 * f[1] - 16, // L
- 500 * (f[0] - f[1]), // a
- 200 * (f[1] - f[2]) // b
- ];
-}
-
-function rgb2hsl(r, g, b) {
- r /= 255;
- g /= 255;
- b /= 255;
- let h, s, l;
- const M = Math.max(r, g, b);
- const m = Math.min(r, g, b);
- const d = M - m;
- if (d === 0) {
- h = 0;
- } else if (M === r) {
- h = ((g - b) / d) % 6;
- } else if (M === g) {
- h = (b - r) / d + 2;
- } else {
- h = (r - g) / d + 4;
- }
-
- h *= 60;
-
- if (h < 0) {
- h += 360;
- }
-
- l = (M + m) / 2;
-
- if (d === 0) {
- s = 0;
- } else {
- s = d / (1 - Math.abs(2 * l - 1));
- }
-
- s *= 100;
- l *= 100;
-
- return [Math.round(h), Math.round(s), Math.round(l)];
-}
-
-function rgb2hwb(rgb_r, rgb_g, rgb_b) {
- rgb_r /= 255;
- rgb_g /= 255;
- rgb_b /= 255;
-
- const w = Math.min(rgb_r, rgb_g, rgb_b);
- const v = Math.max(rgb_r, rgb_g, rgb_b);
-
- const b = 1 - v;
-
- if (v === w) {
- return [0, Math.round(w * 100), Math.round(b * 100)];
- }
-
- const f =
- rgb_r === w ? rgb_g - rgb_b : rgb_g === w ? rgb_b - rgb_r : rgb_r - rgb_g;
- const i = rgb_r === w ? 3 : rgb_g === w ? 5 : 1;
-
- return [
- Math.round((i - f / (v - w)) / 6 * 360) % 360,
- Math.round(w * 100),
- Math.round(b * 100)
- ];
-}
-
-function perc255(value) {
- return Math.round(value * 100 / 255) + "%";
-}
-
-function generateColorFuncs(hexString) {
- if (hexString.length !== 7) {
- throw new Error(
- "Invalid hex string color definition (" +
- hexString +
- ") - expected 6 character hex string"
- );
- }
- const rgb = [0, 0, 0];
- for (let i = 0; i < 3; i += 1) {
- rgb[i] = parseInt(hexString.substr(2 * i + 1, 2), 16);
- }
- const hsl = rgb2hsl(rgb[0], rgb[1], rgb[2]);
- const hwb = rgb2hwb(rgb[0], rgb[1], rgb[2]);
- const func = [];
- const rgbStr = rgb[0] + "," + rgb[1] + "," + rgb[2];
- const rgbPercStr =
- perc255(rgb[0]) + "," + perc255(rgb[1]) + "," + perc255(rgb[2]);
- const hslStr = hsl[0] + "," + hsl[1] + "%," + hsl[2] + "%";
- const hwbStr = hwb[0] + "," + hwb[1] + "%," + hwb[2] + "%";
-
- // *very* convoluted process, just to be able to establish if the color
- // is gray -- or not.
- const linRgb = lin_sRGB([rgb[0] / 255, rgb[1] / 255, rgb[2] / 255]);
- const xyz_d65 = srgb2xyz(linRgb);
- const xyz_d50 = chromaticAdaptationD65_D50(xyz_d65);
- const lab = xyz2lab(xyz_d50);
-
- func.push("rgb(" + rgbStr + ")");
- func.push("rgba(" + rgbStr + ",1)");
- func.push("rgba(" + rgbStr + ",100%)");
- func.push("rgb(" + rgbPercStr + ")");
- func.push("rgba(" + rgbPercStr + ",1)");
- func.push("rgba(" + rgbPercStr + ",100%)");
- func.push("hsl(" + hslStr + ")");
- func.push("hsla(" + hslStr + ",1)");
- func.push("hsla(" + hslStr + ",100%)");
- func.push("hwb(" + hwbStr + ")");
- func.push("hwb(" + hwbStr + ",1)");
- func.push("hwb(" + hwbStr + ",100%)");
-
- // technically, this should be 0 - but then #808080 wouldn't even be gray
- if (lab[1] * lab[1] < 0.01 && lab[2] * lab[2] < 0.01) {
- // yay! gray!
- const grayStr = Math.round(lab[0]);
- func.push("gray(" + grayStr + ")");
- func.push("gray(" + grayStr + ",1)");
- func.push("gray(" + grayStr + ",100%)");
- func.push("gray(" + grayStr + "%)");
- func.push("gray(" + grayStr + "%,1)");
- func.push("gray(" + grayStr + "%,100%)");
- }
- return func;
-}
-
-module.exports = generateColorFuncs;
projects / dotfiles / .git / blobdiff