interface ColorRGB { r: number; g: number; b: number; } interface ColorHSV { h: number; s: number; v: number; } export enum ColorFmt { RGB, // rgb(R,G,B) HEX, // #RRGGBB } function hsvToRgb({ h, s, v }: ColorHSV): ColorRGB { const i = Math.floor(h * 6); const f = h * 6 - i; const p = v * (1 - s); const q = v * (1 - f * s); const t = v * (1 - (1 - f) * s); switch (i % 6) { case 0: return { r: v, g: t, b: p }; case 1: return { r: q, g: v, b: p }; case 2: return { r: p, g: v, b: t }; case 3: return { r: p, g: q, b: v }; case 4: return { r: t, g: p, b: v }; case 5: return { r: v, g: p, b: q }; default: throw new Error("unreacheable"); } } function rgbToHsv({ r, g, b }: ColorRGB): ColorHSV { const max = Math.max(r, g, b); const min = Math.min(r, g, b); const v = max; const d = max - min; const s = max === 0 ? 0 : d / max; let h; if (max === min) { h = 0; // achromatic } else { switch (max) { case r: h = (g - b) / d + (g < b ? 6 : 0); break; case g: h = (b - r) / d + 2; break; case b: h = (r - g) / d + 4; break; default: throw new Error("unreacheable"); } h /= 6; } return { h, s, v }; } // Hacky way to get RGB values FOR SURE! function nameToRGB(name: string): ColorRGB { // Create fake div const fakeDiv = document.createElement("div"); fakeDiv.style.color = name; document.body.appendChild(fakeDiv); // Get color of div const cs = window.getComputedStyle(fakeDiv); const pv = cs.getPropertyValue("color"); // Remove div after obtaining desired color value document.body.removeChild(fakeDiv); return parseColor(pv); } // If you also wonder "What the fuck", go here: // https://stackoverflow.com/questions/11068240/what-is-the-most-efficient-way-to-parse-a-css-color-in-javascript function parseColor(input: string): ColorRGB { // Hex format if (input.substr(0, 1) === "#") { const collen = (input.length - 1) / 3; const fact = [17, 1, 0.062272][collen - 1]; return { r: Math.round(parseInt(input.substr(1, collen), 16) * fact) / 256, g: Math.round(parseInt(input.substr(1 + collen, collen), 16) * fact) / 256, b: Math.round(parseInt(input.substr(1 + 2 * collen, collen), 16) * fact) / 256, }; } if (input.startsWith("rgb")) { // RGB() format const vals = input .split("(")[1] .split(")")[0] .split(",") .map((i) => parseInt(i, 10)) .map(Math.round); return { r: vals[0] / 256, g: vals[1] / 256, b: vals[2] / 256 }; } // Fuck, well.. normalize it and put it into an element and get back to me return nameToRGB(input); } function serializeColor(col: ColorRGB, format: ColorFmt): string { const r = Math.round(col.r * 255); const g = Math.round(col.g * 255); const b = Math.round(col.b * 255); switch (format) { case ColorFmt.RGB: return `rgb(${r}, ${g}, ${b})`; case ColorFmt.HEX: { const rhex = `00${r.toString(16)}`.slice(-2); const ghex = `00${g.toString(16)}`.slice(-2); const bhex = `00${b.toString(16)}`.slice(-2); return `#${rhex}${ghex}${bhex}`; } default: return "#000"; } } export function darken(color: string, format: ColorFmt): string { const col = parseColor(color); const hsl = rgbToHsv(col); if (hsl.s < 0.15) { hsl.h = 0.6; hsl.s = 0.5; hsl.v = Math.max(0.2, 1 - hsl.v); } else if (hsl.v > 0.5) { hsl.v = 0.4; if (hsl.s > 0.2) { hsl.s = Math.min(1, hsl.s + 0.2); } } const out = hsvToRgb(hsl); return serializeColor(out, format); } export function lighten(color: string, format: ColorFmt): string { const col = parseColor(color); const hsl = rgbToHsv(col); if (hsl.v < 0.5) { hsl.v = 0.8; } if (hsl.s > 0.7) { hsl.s = Math.min(1, hsl.s - 0.3); hsl.v = 1; } // Blue is shit to read, make it cyan if (Math.abs(hsl.h - 0.666) < 0.1) { hsl.h -= 0.13; hsl.v = Math.min(1, hsl.v + 0.1); } const out = hsvToRgb(hsl); return serializeColor(out, format); }