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import guard from './guard';
import ColorError from './ColorError';
/**
* Parses a color into red, gree, blue, alpha parts
*
* @param color the input color. Can be a RGB, RBGA, HSL, HSLA, or named color
*/
function parseToRgba(color: string): [number, number, number, number] {
if (typeof color !== 'string') throw new ColorError(color);
if (color.trim().toLowerCase() === 'transparent') return [0, 0, 0, 0];
let normalizedColor = color.trim();
normalizedColor = namedColorRegex.test(color) ? nameToHex(color) : color;
const reducedHexMatch = reducedHexRegex.exec(normalizedColor);
if (reducedHexMatch) {
const arr = Array.from(reducedHexMatch).slice(1);
return [
...arr.slice(0, 3).map((x) => parseInt(r(x, 2), 16)),
parseInt(r(arr[3] || 'f', 2), 16) / 255,
] as [number, number, number, number];
}
const hexMatch = hexRegex.exec(normalizedColor);
if (hexMatch) {
const arr = Array.from(hexMatch).slice(1);
return [
...arr.slice(0, 3).map((x) => parseInt(x, 16)),
parseInt(arr[3] || 'ff', 16) / 255,
] as [number, number, number, number];
}
const rgbaMatch = rgbaRegex.exec(normalizedColor);
if (rgbaMatch) {
const arr = Array.from(rgbaMatch).slice(1);
return [
...arr.slice(0, 3).map((x) => parseInt(x, 10)),
parseFloat(arr[3] || '1'),
] as [number, number, number, number];
}
const hslaMatch = hslaRegex.exec(normalizedColor);
if (hslaMatch) {
const [h, s, l, a] = Array.from(hslaMatch).slice(1).map(parseFloat);
if (guard(0, 100, s) !== s) throw new ColorError(color);
if (guard(0, 100, l) !== l) throw new ColorError(color);
return [...hslToRgb(h, s, l), a || 1] as [number, number, number, number];
}
throw new ColorError(color);
}
function hash(str: string) {
let hash = 5381;
let i = str.length;
while (i) {
hash = (hash * 33) ^ str.charCodeAt(--i);
}
/* JavaScript does bitwise operations (like XOR, above) on 32-bit signed
* integers. Since we want the results to be always positive, convert the
* signed int to an unsigned by doing an unsigned bitshift. */
return (hash >>> 0) % 2341;
}
const colorToInt = (x: string) => parseInt(x.replace(/_/g, ''), 36);
const compressedColorMap = '1q29ehhb 1n09sgk7 1kl1ekf_ _yl4zsno 16z9eiv3 1p29lhp8 _bd9zg04 17u0____ _iw9zhe5 _to73___ _r45e31e _7l6g016 _jh8ouiv _zn3qba8 1jy4zshs 11u87k0u 1ro9yvyo 1aj3xael 1gz9zjz0 _3w8l4xo 1bf1ekf_ _ke3v___ _4rrkb__ 13j776yz _646mbhl _nrjr4__ _le6mbhl 1n37ehkb _m75f91n _qj3bzfz 1939yygw 11i5z6x8 _1k5f8xs 1509441m 15t5lwgf _ae2th1n _tg1ugcv 1lp1ugcv 16e14up_ _h55rw7n _ny9yavn _7a11xb_ 1ih442g9 _pv442g9 1mv16xof 14e6y7tu 1oo9zkds 17d1cisi _4v9y70f _y98m8kc 1019pq0v 12o9zda8 _348j4f4 1et50i2o _8epa8__ _ts6senj 1o350i2o 1mi9eiuo 1259yrp0 1ln80gnw _632xcoy 1cn9zldc _f29edu4 1n490c8q _9f9ziet 1b94vk74 _m49zkct 1kz6s73a 1eu9dtog _q58s1rz 1dy9sjiq __u89jo3 _aj5nkwg _ld89jo3 13h9z6wx _qa9z2ii _l119xgq _bs5arju 1hj4nwk9 1qt4nwk9 1ge6wau6 14j9zlcw 11p1edc_ _ms1zcxe _439shk6 _jt9y70f _754zsow 1la40eju _oq5p___ _x279qkz 1fa5r3rv _yd2d9ip _424tcku _8y1di2_ _zi2uabw _yy7rn9h 12yz980_ __39ljp6 1b59zg0x _n39zfzp 1fy9zest _b33k___ _hp9wq92 1il50hz4 _io472ub _lj9z3eo 19z9ykg0 _8t8iu3a 12b9bl4a 1ak5yw0o _896v4ku _tb8k8lv _s59zi6t _c09ze0p 1lg80oqn 1id9z8wb _238nba5 1kq6wgdi _154zssg _tn3zk49 _da9y6tc 1sg7cv4f _r12jvtt 1gq5fmkz 1cs9rvci _lp9jn1c _xw1tdnb 13f9zje6 16f6973h _vo7ir40 _bt5arjf _rc45e4t _hr4e100 10v4e100 _hc9zke2 _w91egv_ _sj2r1kk 13c87yx8 _vqpds__ _ni8ggk8 _tj9yqfb 1ia2j4r4 _7x9b10u 1fc9ld4j 1eq9zldr _5j9lhpx _ez9zl6o _md61fzm'
.split(' ')
.reduce((acc, next) => {
const key = colorToInt(next.substring(0, 3));
const hex = colorToInt(next.substring(3)).toString(16);
// NOTE: padStart could be used here but it breaks Node 6 compat
// https://github.com/ricokahler/color2k/issues/351
let prefix = '';
for (let i = 0; i < 6 - hex.length; i++) {
prefix += '0';
}
acc[key] = `${prefix}${hex}`;
return acc;
}, {} as { [key: string]: string });
/**
* Checks if a string is a CSS named color and returns its equivalent hex value, otherwise returns the original color.
*/
function nameToHex(color: string): string {
const normalizedColorName = color.toLowerCase().trim();
const result = compressedColorMap[hash(normalizedColorName)];
if (!result) throw new ColorError(color);
return `#${result}`;
}
const r = (str: string, amount: number) =>
Array.from(Array(amount))
.map(() => str)
.join('');
const reducedHexRegex = new RegExp(`^#${r('([a-f0-9])', 3)}([a-f0-9])?$`, 'i');
const hexRegex = new RegExp(`^#${r('([a-f0-9]{2})', 3)}([a-f0-9]{2})?$`, 'i');
const rgbaRegex = new RegExp(
`^rgba?\\(\\s*(\\d+)\\s*${r(
',\\s*(\\d+)\\s*',
2
)}(?:,\\s*([\\d.]+))?\\s*\\)$`,
'i'
);
const hslaRegex = /^hsla?\(\s*([\d.]+)\s*,\s*([\d.]+)%\s*,\s*([\d.]+)%(?:\s*,\s*([\d.]+))?\s*\)$/i;
const namedColorRegex = /^[a-z]+$/i;
const roundColor = (color: number): number => {
return Math.round(color * 255);
};
const hslToRgb = (
hue: number,
saturation: number,
lightness: number
): [number, number, number] => {
let l = lightness / 100;
if (saturation === 0) {
// achromatic
return [l, l, l].map(roundColor) as [number, number, number];
}
// formulae from https://en.wikipedia.org/wiki/HSL_and_HSV
const huePrime = (((hue % 360) + 360) % 360) / 60;
const chroma = (1 - Math.abs(2 * l - 1)) * (saturation / 100);
const secondComponent = chroma * (1 - Math.abs((huePrime % 2) - 1));
let red = 0;
let green = 0;
let blue = 0;
if (huePrime >= 0 && huePrime < 1) {
red = chroma;
green = secondComponent;
} else if (huePrime >= 1 && huePrime < 2) {
red = secondComponent;
green = chroma;
} else if (huePrime >= 2 && huePrime < 3) {
green = chroma;
blue = secondComponent;
} else if (huePrime >= 3 && huePrime < 4) {
green = secondComponent;
blue = chroma;
} else if (huePrime >= 4 && huePrime < 5) {
red = secondComponent;
blue = chroma;
} else if (huePrime >= 5 && huePrime < 6) {
red = chroma;
blue = secondComponent;
}
const lightnessModification = l - chroma / 2;
const finalRed = red + lightnessModification;
const finalGreen = green + lightnessModification;
const finalBlue = blue + lightnessModification;
return [finalRed, finalGreen, finalBlue].map(roundColor) as [
number,
number,
number
];
};
export default parseToRgba;