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diff --git a/src/services/color_convert/color_convert.js b/src/services/color_convert/color_convert.js
index aa7dc8b940..9e3560f57e 100644
--- a/src/services/color_convert/color_convert.js
+++ b/src/services/color_convert/color_convert.js
@@ -1,242 +1,242 @@
import { invertLightness, contrastRatio, convert } from 'chromatism'
// useful for visualizing color when debugging
export const consoleColor = (color) => console.log('%c##########', 'background: ' + color + '; color: ' + color)
/**
* Convert r, g, b values into hex notation. All components are [0-255]
*
* @param {Number|String|Object} r - Either red component, {r,g,b} object, or hex string
* @param {Number} [g] - Green component
* @param {Number} [b] - Blue component
*/
export const rgb2hex = (r, g, b) => {
if (r === null || typeof r === 'undefined') {
return undefined
}
// TODO: clean up this mess
if (r[0] === '#' || r === 'transparent') {
return r
}
if (typeof r === 'object') {
({ r, g, b } = r)
}
[r, g, b] = [r, g, b].map(val => {
val = Math.ceil(val)
val = val < 0 ? 0 : val
val = val > 255 ? 255 : val
return val
})
return `#${((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1)}`
}
/**
* Converts 8-bit RGB component into linear component
* https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
* https://www.w3.org/TR/2008/REC-WCAG20-20081211/relative-luminance.xml
* https://en.wikipedia.org/wiki/SRGB#The_reverse_transformation
*
* @param {Number} bit - color component [0..255]
* @returns {Number} linear component [0..1]
*/
const c2linear = (bit) => {
// W3C gives 0.03928 while wikipedia states 0.04045
// what those magical numbers mean - I don't know.
// something about gamma-correction, i suppose.
// Sticking with W3C example.
const c = bit / 255
if (c < 0.03928) {
return c / 12.92
} else {
return Math.pow((c + 0.055) / 1.055, 2.4)
}
}
/**
* Converts sRGB into linear RGB
* @param {Object} srgb - sRGB color
* @returns {Object} linear rgb color
*/
const srgbToLinear = (srgb) => {
return 'rgb'.split('').reduce((acc, c) => { acc[c] = c2linear(srgb[c]); return acc }, {})
}
/**
* Calculates relative luminance for given color
* https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
* https://www.w3.org/TR/2008/REC-WCAG20-20081211/relative-luminance.xml
*
* @param {Object} srgb - sRGB color
* @returns {Number} relative luminance
*/
export const relativeLuminance = (srgb) => {
const { r, g, b } = srgbToLinear(srgb)
return 0.2126 * r + 0.7152 * g + 0.0722 * b
}
/**
* Generates color ratio between two colors. Order is unimporant
* https://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef
*
* @param {Object} a - sRGB color
* @param {Object} b - sRGB color
* @returns {Number} color ratio
*/
export const getContrastRatio = (a, b) => {
const la = relativeLuminance(a)
const lb = relativeLuminance(b)
const [l1, l2] = la > lb ? [la, lb] : [lb, la]
return (l1 + 0.05) / (l2 + 0.05)
}
/**
* Same as `getContrastRatio` but for multiple layers in-between
*
* @param {Object} text - text color (topmost layer)
* @param {[Object, Number]} layers[] - layers between text and bedrock
* @param {Object} bedrock - layer at the very bottom
*/
export const getContrastRatioLayers = (text, layers, bedrock) => {
return getContrastRatio(alphaBlendLayers(bedrock, layers), text)
}
/**
* This performs alpha blending between solid background and semi-transparent foreground
*
* @param {Object} fg - top layer color
* @param {Number} fga - top layer's alpha
* @param {Object} bg - bottom layer color
* @returns {Object} sRGB of resulting color
*/
export const alphaBlend = (fg, fga, bg) => {
if (fga === 1 || typeof fga === 'undefined') return fg
return 'rgb'.split('').reduce((acc, c) => {
// Simplified https://en.wikipedia.org/wiki/Alpha_compositing#Alpha_blending
// for opaque bg and transparent fg
acc[c] = (fg[c] * fga + bg[c] * (1 - fga))
return acc
}, {})
}
/**
* Same as `alphaBlend` but for multiple layers in-between
*
* @param {Object} bedrock - layer at the very bottom
* @param {[Object, Number]} layers[] - layers between text and bedrock
*/
export const alphaBlendLayers = (bedrock, layers) => layers.reduce((acc, [color, opacity]) => {
return alphaBlend(color, opacity, acc)
}, bedrock)
export const invert = (rgb) => {
return 'rgb'.split('').reduce((acc, c) => {
acc[c] = 255 - rgb[c]
return acc
}, {})
}
/**
* Converts #rrggbb hex notation into an {r, g, b} object
*
* @param {String} hex - #rrggbb string
* @returns {Object} rgb representation of the color, values are 0-255
*/
export const hex2rgb = (hex) => {
const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex)
return result
? {
r: parseInt(result[1], 16),
g: parseInt(result[2], 16),
b: parseInt(result[3], 16)
}
: null
}
/**
* Old somewhat weird function for mixing two colors together
*
* @param {Object} a - one color (rgb)
* @param {Object} b - other color (rgb)
* @returns {Object} result
*/
export const mixrgb = (a, b) => {
return 'rgb'.split('').reduce((acc, k) => {
acc[k] = (a[k] + b[k]) / 2
return acc
}, {})
}
/**
* Converts rgb object into a CSS rgba() color
*
* @param {Object} color - rgb
* @returns {String} CSS rgba() color
*/
export const rgba2css = function (rgba) {
return `rgba(${Math.floor(rgba.r)}, ${Math.floor(rgba.g)}, ${Math.floor(rgba.b)}, ${rgba.a ?? 1})`
}
/**
* Get text color for given background color and intended text color
* This checks if text and background don't have enough color and inverts
* text color's lightness if needed. If text color is still not enough it
* will fall back to black or white
*
* @param {Object} bg - background color
* @param {Object} text - intended text color
* @param {Boolean} preserve - try to preserve intended text color's hue/saturation (i.e. no BW)
*/
export const getTextColor = function (bg, text, preserve) {
const originalContrast = getContrastRatio(bg, text)
if (!preserve) {
if (originalContrast < 4.5) {
// B&W
return contrastRatio(bg, text).rgb
}
}
const originalColor = convert(text).hex
const invertedColor = invertLightness(originalColor).hex
const invertedContrast = getContrastRatio(bg, convert(invertedColor).rgb)
let workColor
if (invertedContrast > originalContrast) {
workColor = invertedColor
} else {
workColor = originalColor
}
let contrast = getContrastRatio(bg, text)
const result = convert(rgb2hex(workColor)).hsl
const delta = result.l > 50 ? 1 : -1
const multiplier = 10
- while (contrast < 4.5 && result.l > 0 && result.l < 100) {
+ while (contrast < 4.5 && result.l > 20 && result.l < 80) {
result.l += delta * multiplier
contrast = getContrastRatio(bg, convert(result).rgb)
console.log(convert(result).hex, result.l, contrast)
}
const base = typeof text.a !== 'undefined' ? { a: text.a } : {}
return Object.assign(convert(result).rgb, base)
}
/**
* Converts color to CSS Color value
*
* @param {Object|String} input - color
* @param {Number} [a] - alpha value
* @returns {String} a CSS Color value
*/
export const getCssColor = (input, a) => {
let rgb = {}
if (typeof input === 'object') {
rgb = input
} else if (typeof input === 'string') {
if (input.startsWith('#')) {
rgb = hex2rgb(input)
} else {
return input
}
}
return rgba2css({ ...rgb, a })
}

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