const colorString = require('color-string');
const convert = require('color-convert');
const skippedModels = [
// To be honest, I don't really feel like keyword belongs in color convert, but eh.
'keyword',
// Gray conflicts with some method names, and has its own method defined.
'gray',
// Shouldn't really be in color-convert either...
'hex',
];
const hashedModelKeys = {};
for (const model of Object.keys(convert)) {
hashedModelKeys[[...convert[model].labels].sort().join('')] = model;
}
const limiters = {};
function Color(object, model) {
if (!(this instanceof Color)) {
return new Color(object, model);
}
if (model && model in skippedModels) {
model = null;
}
if (model && !(model in convert)) {
throw new Error('Unknown model: ' + model);
}
let i;
let channels;
if (object == null) { // eslint-disable-line no-eq-null,eqeqeq
this.model = 'rgb';
this.color = [0, 0, 0];
this.valpha = 1;
} else if (object instanceof Color) {
this.model = object.model;
this.color = [...object.color];
this.valpha = object.valpha;
} else if (typeof object === 'string') {
const result = colorString.get(object);
if (result === null) {
throw new Error('Unable to parse color from string: ' + object);
}
this.model = result.model;
channels = convert[this.model].channels;
this.color = result.value.slice(0, channels);
this.valpha = typeof result.value[channels] === 'number' ? result.value[channels] : 1;
} else if (object.length > 0) {
this.model = model || 'rgb';
channels = convert[this.model].channels;
const newArray = Array.prototype.slice.call(object, 0, channels);
this.color = zeroArray(newArray, channels);
this.valpha = typeof object[channels] === 'number' ? object[channels] : 1;
} else if (typeof object === 'number') {
// This is always RGB - can be converted later on.
this.model = 'rgb';
this.color = [
(object >> 16) & 0xFF,
(object >> 8) & 0xFF,
object & 0xFF,
];
this.valpha = 1;
} else {
this.valpha = 1;
const keys = Object.keys(object);
if ('alpha' in object) {
keys.splice(keys.indexOf('alpha'), 1);
this.valpha = typeof object.alpha === 'number' ? object.alpha : 0;
}
const hashedKeys = keys.sort().join('');
if (!(hashedKeys in hashedModelKeys)) {
throw new Error('Unable to parse color from object: ' + JSON.stringify(object));
}
this.model = hashedModelKeys[hashedKeys];
const {labels} = convert[this.model];
const color = [];
for (i = 0; i < labels.length; i++) {
color.push(object[labels[i]]);
}
this.color = zeroArray(color);
}
// Perform limitations (clamping, etc.)
if (limiters[this.model]) {
channels = convert[this.model].channels;
for (i = 0; i < channels; i++) {
const limit = limiters[this.model][i];
if (limit) {
this.color[i] = limit(this.color[i]);
}
}
}
this.valpha = Math.max(0, Math.min(1, this.valpha));
if (Object.freeze) {
Object.freeze(this);
}
}
Color.prototype = {
toString() {
return this.string();
},
toJSON() {
return this[this.model]();
},
string(places) {
let self = this.model in colorString.to ? this : this.rgb();
self = self.round(typeof places === 'number' ? places : 1);
const args = self.valpha === 1 ? self.color : [...self.color, this.valpha];
return colorString.to[self.model](args);
},
percentString(places) {
const self = this.rgb().round(typeof places === 'number' ? places : 1);
const args = self.valpha === 1 ? self.color : [...self.color, this.valpha];
return colorString.to.rgb.percent(args);
},
array() {
return this.valpha === 1 ? [...this.color] : [...this.color, this.valpha];
},
object() {
const result = {};
const {channels} = convert[this.model];
const {labels} = convert[this.model];
for (let i = 0; i < channels; i++) {
result[labels[i]] = this.color[i];
}
if (this.valpha !== 1) {
result.alpha = this.valpha;
}
return result;
},
unitArray() {
const rgb = this.rgb().color;
rgb[0] /= 255;
rgb[1] /= 255;
rgb[2] /= 255;
if (this.valpha !== 1) {
rgb.push(this.valpha);
}
return rgb;
},
unitObject() {
const rgb = this.rgb().object();
rgb.r /= 255;
rgb.g /= 255;
rgb.b /= 255;
if (this.valpha !== 1) {
rgb.alpha = this.valpha;
}
return rgb;
},
round(places) {
places = Math.max(places || 0, 0);
return new Color([...this.color.map(roundToPlace(places)), this.valpha], this.model);
},
alpha(value) {
if (value !== undefined) {
return new Color([...this.color, Math.max(0, Math.min(1, value))], this.model);
}
return this.valpha;
},
// Rgb
red: getset('rgb', 0, maxfn(255)),
green: getset('rgb', 1, maxfn(255)),
blue: getset('rgb', 2, maxfn(255)),
hue: getset(['hsl', 'hsv', 'hsl', 'hwb', 'hcg'], 0, value => ((value % 360) + 360) % 360),
saturationl: getset('hsl', 1, maxfn(100)),
lightness: getset('hsl', 2, maxfn(100)),
saturationv: getset('hsv', 1, maxfn(100)),
value: getset('hsv', 2, maxfn(100)),
chroma: getset('hcg', 1, maxfn(100)),
gray: getset('hcg', 2, maxfn(100)),
white: getset('hwb', 1, maxfn(100)),
wblack: getset('hwb', 2, maxfn(100)),
cyan: getset('cmyk', 0, maxfn(100)),
magenta: getset('cmyk', 1, maxfn(100)),
yellow: getset('cmyk', 2, maxfn(100)),
black: getset('cmyk', 3, maxfn(100)),
x: getset('xyz', 0, maxfn(95.047)),
y: getset('xyz', 1, maxfn(100)),
z: getset('xyz', 2, maxfn(108.833)),
l: getset('lab', 0, maxfn(100)),
a: getset('lab', 1),
b: getset('lab', 2),
keyword(value) {
if (value !== undefined) {
return new Color(value);
}
return convert[this.model].keyword(this.color);
},
hex(value) {
if (value !== undefined) {
return new Color(value);
}
return colorString.to.hex(this.rgb().round().color);
},
hexa(value) {
if (value !== undefined) {
return new Color(value);
}
const rgbArray = this.rgb().round().color;
let alphaHex = Math.round(this.valpha * 255).toString(16).toUpperCase();
if (alphaHex.length === 1) {
alphaHex = '0' + alphaHex;
}
return colorString.to.hex(rgbArray) + alphaHex;
},
rgbNumber() {
const rgb = this.rgb().color;
return ((rgb[0] & 0xFF) << 16) | ((rgb[1] & 0xFF) << 8) | (rgb[2] & 0xFF);
},
luminosity() {
// http://www.w3.org/TR/WCAG20/#relativeluminancedef
const rgb = this.rgb().color;
const lum = [];
for (const [i, element] of rgb.entries()) {
const chan = element / 255;
lum[i] = (chan <= 0.04045) ? chan / 12.92 : ((chan + 0.055) / 1.055) ** 2.4;
}
return 0.2126 * lum[0] + 0.7152 * lum[1] + 0.0722 * lum[2];
},
contrast(color2) {
// http://www.w3.org/TR/WCAG20/#contrast-ratiodef
const lum1 = this.luminosity();
const lum2 = color2.luminosity();
if (lum1 > lum2) {
return (lum1 + 0.05) / (lum2 + 0.05);
}
return (lum2 + 0.05) / (lum1 + 0.05);
},
level(color2) {
// https://www.w3.org/TR/WCAG/#contrast-enhanced
const contrastRatio = this.contrast(color2);
if (contrastRatio >= 7) {
return 'AAA';
}
return (contrastRatio >= 4.5) ? 'AA' : '';
},
isDark() {
// YIQ equation from http://24ways.org/2010/calculating-color-contrast
const rgb = this.rgb().color;
const yiq = (rgb[0] * 2126 + rgb[1] * 7152 + rgb[2] * 722) / 10000;
return yiq < 128;
},
isLight() {
return !this.isDark();
},
negate() {
const rgb = this.rgb();
for (let i = 0; i < 3; i++) {
rgb.color[i] = 255 - rgb.color[i];
}
return rgb;
},
lighten(ratio) {
const hsl = this.hsl();
hsl.color[2] += hsl.color[2] * ratio;
return hsl;
},
darken(ratio) {
const hsl = this.hsl();
hsl.color[2] -= hsl.color[2] * ratio;
return hsl;
},
saturate(ratio) {
const hsl = this.hsl();
hsl.color[1] += hsl.color[1] * ratio;
return hsl;
},
desaturate(ratio) {
const hsl = this.hsl();
hsl.color[1] -= hsl.color[1] * ratio;
return hsl;
},
whiten(ratio) {
const hwb = this.hwb();
hwb.color[1] += hwb.color[1] * ratio;
return hwb;
},
blacken(ratio) {
const hwb = this.hwb();
hwb.color[2] += hwb.color[2] * ratio;
return hwb;
},
grayscale() {
// http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale
const rgb = this.rgb().color;
const value = rgb[0] * 0.3 + rgb[1] * 0.59 + rgb[2] * 0.11;
return Color.rgb(value, value, value);
},
fade(ratio) {
return this.alpha(this.valpha - (this.valpha * ratio));
},
opaquer(ratio) {
return this.alpha(this.valpha + (this.valpha * ratio));
},
rotate(degrees) {
const hsl = this.hsl();
let hue = hsl.color[0];
hue = (hue + degrees) % 360;
hue = hue < 0 ? 360 + hue : hue;
hsl.color[0] = hue;
return hsl;
},
mix(mixinColor, weight) {
// Ported from sass implementation in C
// https://github.com/sass/libsass/blob/0e6b4a2850092356aa3ece07c6b249f0221caced/functions.cpp#L209
if (!mixinColor || !mixinColor.rgb) {
throw new Error('Argument to "mix" was not a Color instance, but rather an instance of ' + typeof mixinColor);
}
const color1 = mixinColor.rgb();
const color2 = this.rgb();
const p = weight === undefined ? 0.5 : weight;
const w = 2 * p - 1;
const a = color1.alpha() - color2.alpha();
const w1 = (((w * a === -1) ? w : (w + a) / (1 + w * a)) + 1) / 2;
const w2 = 1 - w1;
return Color.rgb(
w1 * color1.red() + w2 * color2.red(),
w1 * color1.green() + w2 * color2.green(),
w1 * color1.blue() + w2 * color2.blue(),
color1.alpha() * p + color2.alpha() * (1 - p));
},
};
// Model conversion methods and static constructors
for (const model of Object.keys(convert)) {
if (skippedModels.includes(model)) {
continue;
}
const {channels} = convert[model];
// Conversion methods
Color.prototype[model] = function (...args) {
if (this.model === model) {
return new Color(this);
}
if (args.length > 0) {
return new Color(args, model);
}
return new Color([...assertArray(convert[this.model][model].raw(this.color)), this.valpha], model);
};
// 'static' construction methods
Color[model] = function (...args) {
let color = args[0];
if (typeof color === 'number') {
color = zeroArray(args, channels);
}
return new Color(color, model);
};
}
function roundTo(number, places) {
return Number(number.toFixed(places));
}
function roundToPlace(places) {
return function (number) {
return roundTo(number, places);
};
}
function getset(model, channel, modifier) {
model = Array.isArray(model) ? model : [model];
for (const m of model) {
(limiters[m] || (limiters[m] = []))[channel] = modifier;
}
model = model[0];
return function (value) {
let result;
if (value !== undefined) {
if (modifier) {
value = modifier(value);
}
result = this[model]();
result.color[channel] = value;
return result;
}
result = this[model]().color[channel];
if (modifier) {
result = modifier(result);
}
return result;
};
}
function maxfn(max) {
return function (v) {
return Math.max(0, Math.min(max, v));
};
}
function assertArray(value) {
return Array.isArray(value) ? value : [value];
}
function zeroArray(array, length) {
for (let i = 0; i < length; i++) {
if (typeof array[i] !== 'number') {
array[i] = 0;
}
}
return array;
}
module.exports = Color;
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