An ATproto social media client -- with an independent Appview.
feat: color representation conversion
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src/alf/util/colors/converstion.ts
+220
src/alf/util/colors/converstion.ts
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export interface HslColor {
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h: number
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s: number
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l: number
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}
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export interface RgbColor {
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r: number
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g: number
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b: number
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}
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export type HexCode = `#${string}` | string
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/**
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* Converts a hexcode string in the format `"#RRGGBB"` to a `HslColor` object (`{ h: number, s: number, l: number }`).
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* @param {HexCode} hex - A hexcode string in the format `#RRGGBB`. The leading "#" symbol is optional.
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* @returns{HslColor} A HSL colour object.
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*/
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export const hexToHsl = (hex: HexCode): HslColor => {
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hex = hex.replace('#', '')
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const r = parseInt(hex.substring(0, 2), 16) / 255
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const g = parseInt(hex.substring(2, 4), 16) / 255
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const b = parseInt(hex.substring(4, 6), 16) / 255
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const max = Math.max(r, g, b)
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const min = Math.min(r, g, b)
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const diff = max - min
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let h = 0,
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s,
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l
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l = (max + min) / 2
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if (diff === 0) {
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h = s = 0
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} else {
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s = l > 0.5 ? diff / (2 - max - min) : diff / (max + min)
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switch (max) {
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case r:
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h = (g - b) / diff + (g < b ? 6 : 0)
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break
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case g:
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h = (b - r) / diff + 2
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break
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case b:
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h = (r - g) / diff + 4
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break
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}
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h /= 6
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}
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return {
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h: h * 360,
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s: s * 100,
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l: l * 100,
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}
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}
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/**
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* Converts a `HslColor` object (`{ h: number, s: number, l: number }`) to a hexcode string in the format `"#RRGGBB"`.
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* @param {HslColor} hsl - A HSL colour object.
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* @param {boolean} appendSymbol - Whether to append "#" to the start of the hex string. Defaults to true.
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* @returns {HexCode} A hexcode string in the format `"#RRGGBB"`. The leading "#" symbol is optional.
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*/
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export const hslToHex = (
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{h, s, l}: HslColor,
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appendSymbol: boolean = true,
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): HexCode => {
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h = (h % 360) / 360
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s = Math.max(0, Math.min(1, s / 100))
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l = Math.max(0, Math.min(1, l / 100))
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let m2: number, m1: number
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if (l <= 0.5) {
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m2 = l * (s + 1)
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} else {
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m2 = l + s - l * s
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}
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m1 = l * 2 - m2
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function hue(hueValue: number) {
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hueValue =
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hueValue < 0 ? hueValue + 1 : hueValue > 1 ? hueValue - 1 : hueValue
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if (hueValue * 6 < 1) {
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return m1 + (m2 - m1) * hueValue * 6
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} else if (hueValue * 2 < 1) {
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return m2
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} else if (hueValue * 3 < 2) {
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return m1 + (m2 - m1) * (2 / 3 - hueValue) * 6
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} else {
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return m1
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}
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}
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const r = hue(h + 1 / 3) * 255
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const g = hue(h) * 255
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const b = hue(h - 1 / 3) * 255
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return `${appendSymbol ? '#' : ''}${r.toString(16)}${g.toString(16)}${b.toString(16)}`
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}
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/**
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* Converts an `RgbColor` object (`{ r: number, g: number, b: number }`) to a hexcode string in the format `"#RRGGBB"`.
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* @param {RgbColor} rgb - An RGB colour object.
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* @param {boolean} appendSymbol - Whether to append "#" to the start of the hex string. Defaults to true.
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* @returns {HexCode} A hexcode string in the format `"#RRGGBB"`. The leading "#" symbol is optional.
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*/
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export const rgbToHex = (
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{r, g, b}: RgbColor,
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appendSymbol: boolean = true,
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): HexCode => {
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return `${appendSymbol ? '#' : ''}${r.toString(16)}${g.toString(16)}${b.toString(16)}`
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}
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/**
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* Converts a hexcode string in the format `"#RRGGBB"` to an `RgbColor` object (`{ r: number, g: number, b: number }`).
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* @param {HexCode} hex - A hexcode string in the format `#RRGGBB`. The leading "#" symbol is optional.
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* @returns {RgbColor} An RGB colour object.
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*/
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export const hexToRgb = (hex: HexCode): RgbColor => {
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hex = hex.replace('#', '')
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const r = parseInt(hex.substring(0, 2), 16) / 255
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const g = parseInt(hex.substring(2, 4), 16) / 255
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const b = parseInt(hex.substring(4, 6), 16) / 255
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return {r, g, b}
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}
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/**
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* Converts an `RgbColor` object (`{ r: number, g: number, b: number }`) to a `HslColor` object (`{ h: number, s: number, l: number }`)
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* @param {RgbColor} - An RGB colour object.
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* @returns {HslColor} A HSL colour object.
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*/
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export const rgbToHsl = ({r, g, b}: RgbColor): HslColor => {
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r = r / 255
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g = g / 255
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b = b / 255
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const max = Math.max(r, g, b)
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const min = Math.min(r, g, b)
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const diff = max - min
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let h = 0,
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s,
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l
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l = (max + min) / 2
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if (diff === 0) {
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h = s = 0
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} else {
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s = l > 0.5 ? diff / (2 - max - min) : diff / (max + min)
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switch (max) {
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case r:
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h = (g - b) / diff + (g < b ? 6 : 0)
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break
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case g:
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h = (b - r) / diff + 2
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break
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case b:
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h = (r - g) / diff + 4
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break
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}
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h /= 6
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}
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return {
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h: h * 360,
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s: s * 100,
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l: l * 100,
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}
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}
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/**
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* Converts a `HslColor` object (`{ h: number, s: number, l: number }`) to a `RgbColor` object (`{ r: number, g: number, b: number }`)
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* @param {HslColor} - A HSL colour object.
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* @returns {RgbColor} An RGB colour object.
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*/
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export const hslToRgb = ({h, s, l}: HslColor): RgbColor => {
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h = (h % 360) / 360
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s = Math.max(0, Math.min(1, s / 100))
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l = Math.max(0, Math.min(1, l / 100))
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let m2: number, m1: number
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if (l <= 0.5) {
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m2 = l * (s + 1)
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} else {
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m2 = l + s - l * s
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}
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m1 = l * 2 - m2
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function hue(hueValue: number) {
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hueValue =
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hueValue < 0 ? hueValue + 1 : hueValue > 1 ? hueValue - 1 : hueValue
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if (hueValue * 6 < 1) {
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return m1 + (m2 - m1) * hueValue * 6
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} else if (hueValue * 2 < 1) {
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return m2
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} else if (hueValue * 3 < 2) {
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return m1 + (m2 - m1) * (2 / 3 - hueValue) * 6
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} else {
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return m1
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}
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}
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const r = hue(h + 1 / 3) * 255
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const g = hue(h) * 255
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const b = hue(h - 1 / 3) * 255
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return {r: Math.round(r), g: Math.round(g), b: Math.round(b)}
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}