2 var cssKeywords = require('color-name');
4 // NOTE: conversions should only return primitive values (i.e. arrays, or
5 // values that give correct `typeof` results).
6 // do not use box values types (i.e. Number(), String(), etc.)
8 var reverseKeywords = {};
9 for (var key in cssKeywords) {
10 if (cssKeywords.hasOwnProperty(key)) {
11 reverseKeywords[cssKeywords[key]] = key;
15 var convert = module.exports = {
16 rgb: {channels: 3, labels: 'rgb'},
17 hsl: {channels: 3, labels: 'hsl'},
18 hsv: {channels: 3, labels: 'hsv'},
19 hwb: {channels: 3, labels: 'hwb'},
20 cmyk: {channels: 4, labels: 'cmyk'},
21 xyz: {channels: 3, labels: 'xyz'},
22 lab: {channels: 3, labels: 'lab'},
23 lch: {channels: 3, labels: 'lch'},
24 hex: {channels: 1, labels: ['hex']},
25 keyword: {channels: 1, labels: ['keyword']},
26 ansi16: {channels: 1, labels: ['ansi16']},
27 ansi256: {channels: 1, labels: ['ansi256']},
28 hcg: {channels: 3, labels: ['h', 'c', 'g']},
29 apple: {channels: 3, labels: ['r16', 'g16', 'b16']},
30 gray: {channels: 1, labels: ['gray']}
33 // hide .channels and .labels properties
34 for (var model in convert) {
35 if (convert.hasOwnProperty(model)) {
36 if (!('channels' in convert[model])) {
37 throw new Error('missing channels property: ' + model);
40 if (!('labels' in convert[model])) {
41 throw new Error('missing channel labels property: ' + model);
44 if (convert[model].labels.length !== convert[model].channels) {
45 throw new Error('channel and label counts mismatch: ' + model);
48 var channels = convert[model].channels;
49 var labels = convert[model].labels;
50 delete convert[model].channels;
51 delete convert[model].labels;
52 Object.defineProperty(convert[model], 'channels', {value: channels});
53 Object.defineProperty(convert[model], 'labels', {value: labels});
57 convert.rgb.hsl = function (rgb) {
61 var min = Math.min(r, g, b);
62 var max = Math.max(r, g, b);
63 var delta = max - min;
70 } else if (r === max) {
72 } else if (g === max) {
73 h = 2 + (b - r) / delta;
74 } else if (b === max) {
75 h = 4 + (r - g) / delta;
78 h = Math.min(h * 60, 360);
88 } else if (l <= 0.5) {
89 s = delta / (max + min);
91 s = delta / (2 - max - min);
94 return [h, s * 100, l * 100];
97 convert.rgb.hsv = function (rgb) {
104 var r = rgb[0] / 255;
105 var g = rgb[1] / 255;
106 var b = rgb[2] / 255;
107 var v = Math.max(r, g, b);
108 var diff = v - Math.min(r, g, b);
109 var diffc = function (c) {
110 return (v - c) / 6 / diff + 1 / 2;
123 } else if (g === v) {
124 h = (1 / 3) + rdif - bdif;
125 } else if (b === v) {
126 h = (2 / 3) + gdif - rdif;
142 convert.rgb.hwb = function (rgb) {
146 var h = convert.rgb.hsl(rgb)[0];
147 var w = 1 / 255 * Math.min(r, Math.min(g, b));
149 b = 1 - 1 / 255 * Math.max(r, Math.max(g, b));
151 return [h, w * 100, b * 100];
154 convert.rgb.cmyk = function (rgb) {
155 var r = rgb[0] / 255;
156 var g = rgb[1] / 255;
157 var b = rgb[2] / 255;
163 k = Math.min(1 - r, 1 - g, 1 - b);
164 c = (1 - r - k) / (1 - k) || 0;
165 m = (1 - g - k) / (1 - k) || 0;
166 y = (1 - b - k) / (1 - k) || 0;
168 return [c * 100, m * 100, y * 100, k * 100];
172 * See https://en.m.wikipedia.org/wiki/Euclidean_distance#Squared_Euclidean_distance
174 function comparativeDistance(x, y) {
176 Math.pow(x[0] - y[0], 2) +
177 Math.pow(x[1] - y[1], 2) +
178 Math.pow(x[2] - y[2], 2)
182 convert.rgb.keyword = function (rgb) {
183 var reversed = reverseKeywords[rgb];
188 var currentClosestDistance = Infinity;
189 var currentClosestKeyword;
191 for (var keyword in cssKeywords) {
192 if (cssKeywords.hasOwnProperty(keyword)) {
193 var value = cssKeywords[keyword];
195 // Compute comparative distance
196 var distance = comparativeDistance(rgb, value);
198 // Check if its less, if so set as closest
199 if (distance < currentClosestDistance) {
200 currentClosestDistance = distance;
201 currentClosestKeyword = keyword;
206 return currentClosestKeyword;
209 convert.keyword.rgb = function (keyword) {
210 return cssKeywords[keyword];
213 convert.rgb.xyz = function (rgb) {
214 var r = rgb[0] / 255;
215 var g = rgb[1] / 255;
216 var b = rgb[2] / 255;
219 r = r > 0.04045 ? Math.pow(((r + 0.055) / 1.055), 2.4) : (r / 12.92);
220 g = g > 0.04045 ? Math.pow(((g + 0.055) / 1.055), 2.4) : (g / 12.92);
221 b = b > 0.04045 ? Math.pow(((b + 0.055) / 1.055), 2.4) : (b / 12.92);
223 var x = (r * 0.4124) + (g * 0.3576) + (b * 0.1805);
224 var y = (r * 0.2126) + (g * 0.7152) + (b * 0.0722);
225 var z = (r * 0.0193) + (g * 0.1192) + (b * 0.9505);
227 return [x * 100, y * 100, z * 100];
230 convert.rgb.lab = function (rgb) {
231 var xyz = convert.rgb.xyz(rgb);
243 x = x > 0.008856 ? Math.pow(x, 1 / 3) : (7.787 * x) + (16 / 116);
244 y = y > 0.008856 ? Math.pow(y, 1 / 3) : (7.787 * y) + (16 / 116);
245 z = z > 0.008856 ? Math.pow(z, 1 / 3) : (7.787 * z) + (16 / 116);
254 convert.hsl.rgb = function (hsl) {
255 var h = hsl[0] / 360;
256 var s = hsl[1] / 100;
257 var l = hsl[2] / 100;
266 return [val, val, val];
278 for (var i = 0; i < 3; i++) {
279 t3 = h + 1 / 3 * -(i - 1);
288 val = t1 + (t2 - t1) * 6 * t3;
289 } else if (2 * t3 < 1) {
291 } else if (3 * t3 < 2) {
292 val = t1 + (t2 - t1) * (2 / 3 - t3) * 6;
303 convert.hsl.hsv = function (hsl) {
305 var s = hsl[1] / 100;
306 var l = hsl[2] / 100;
308 var lmin = Math.max(l, 0.01);
313 s *= (l <= 1) ? l : 2 - l;
314 smin *= lmin <= 1 ? lmin : 2 - lmin;
316 sv = l === 0 ? (2 * smin) / (lmin + smin) : (2 * s) / (l + s);
318 return [h, sv * 100, v * 100];
321 convert.hsv.rgb = function (hsv) {
323 var s = hsv[1] / 100;
324 var v = hsv[2] / 100;
325 var hi = Math.floor(h) % 6;
327 var f = h - Math.floor(h);
328 var p = 255 * v * (1 - s);
329 var q = 255 * v * (1 - (s * f));
330 var t = 255 * v * (1 - (s * (1 - f)));
349 convert.hsv.hsl = function (hsv) {
351 var s = hsv[1] / 100;
352 var v = hsv[2] / 100;
353 var vmin = Math.max(v, 0.01);
359 lmin = (2 - s) * vmin;
361 sl /= (lmin <= 1) ? lmin : 2 - lmin;
365 return [h, sl * 100, l * 100];
368 // http://dev.w3.org/csswg/css-color/#hwb-to-rgb
369 convert.hwb.rgb = function (hwb) {
370 var h = hwb[0] / 360;
371 var wh = hwb[1] / 100;
372 var bl = hwb[2] / 100;
379 // wh + bl cant be > 1
385 i = Math.floor(6 * h);
389 if ((i & 0x01) !== 0) {
393 n = wh + f * (v - wh); // linear interpolation
401 case 0: r = v; g = n; b = wh; break;
402 case 1: r = n; g = v; b = wh; break;
403 case 2: r = wh; g = v; b = n; break;
404 case 3: r = wh; g = n; b = v; break;
405 case 4: r = n; g = wh; b = v; break;
406 case 5: r = v; g = wh; b = n; break;
409 return [r * 255, g * 255, b * 255];
412 convert.cmyk.rgb = function (cmyk) {
413 var c = cmyk[0] / 100;
414 var m = cmyk[1] / 100;
415 var y = cmyk[2] / 100;
416 var k = cmyk[3] / 100;
421 r = 1 - Math.min(1, c * (1 - k) + k);
422 g = 1 - Math.min(1, m * (1 - k) + k);
423 b = 1 - Math.min(1, y * (1 - k) + k);
425 return [r * 255, g * 255, b * 255];
428 convert.xyz.rgb = function (xyz) {
429 var x = xyz[0] / 100;
430 var y = xyz[1] / 100;
431 var z = xyz[2] / 100;
436 r = (x * 3.2406) + (y * -1.5372) + (z * -0.4986);
437 g = (x * -0.9689) + (y * 1.8758) + (z * 0.0415);
438 b = (x * 0.0557) + (y * -0.2040) + (z * 1.0570);
442 ? ((1.055 * Math.pow(r, 1.0 / 2.4)) - 0.055)
446 ? ((1.055 * Math.pow(g, 1.0 / 2.4)) - 0.055)
450 ? ((1.055 * Math.pow(b, 1.0 / 2.4)) - 0.055)
453 r = Math.min(Math.max(0, r), 1);
454 g = Math.min(Math.max(0, g), 1);
455 b = Math.min(Math.max(0, b), 1);
457 return [r * 255, g * 255, b * 255];
460 convert.xyz.lab = function (xyz) {
472 x = x > 0.008856 ? Math.pow(x, 1 / 3) : (7.787 * x) + (16 / 116);
473 y = y > 0.008856 ? Math.pow(y, 1 / 3) : (7.787 * y) + (16 / 116);
474 z = z > 0.008856 ? Math.pow(z, 1 / 3) : (7.787 * z) + (16 / 116);
483 convert.lab.xyz = function (lab) {
495 var y2 = Math.pow(y, 3);
496 var x2 = Math.pow(x, 3);
497 var z2 = Math.pow(z, 3);
498 y = y2 > 0.008856 ? y2 : (y - 16 / 116) / 7.787;
499 x = x2 > 0.008856 ? x2 : (x - 16 / 116) / 7.787;
500 z = z2 > 0.008856 ? z2 : (z - 16 / 116) / 7.787;
509 convert.lab.lch = function (lab) {
517 hr = Math.atan2(b, a);
518 h = hr * 360 / 2 / Math.PI;
524 c = Math.sqrt(a * a + b * b);
529 convert.lch.lab = function (lch) {
537 hr = h / 360 * 2 * Math.PI;
538 a = c * Math.cos(hr);
539 b = c * Math.sin(hr);
544 convert.rgb.ansi16 = function (args) {
548 var value = 1 in arguments ? arguments[1] : convert.rgb.hsv(args)[2]; // hsv -> ansi16 optimization
550 value = Math.round(value / 50);
557 + ((Math.round(b / 255) << 2)
558 | (Math.round(g / 255) << 1)
559 | Math.round(r / 255));
568 convert.hsv.ansi16 = function (args) {
569 // optimization here; we already know the value and don't need to get
570 // it converted for us.
571 return convert.rgb.ansi16(convert.hsv.rgb(args), args[2]);
574 convert.rgb.ansi256 = function (args) {
579 // we use the extended greyscale palette here, with the exception of
580 // black and white. normal palette only has 4 greyscale shades.
581 if (r === g && g === b) {
590 return Math.round(((r - 8) / 247) * 24) + 232;
594 + (36 * Math.round(r / 255 * 5))
595 + (6 * Math.round(g / 255 * 5))
596 + Math.round(b / 255 * 5);
601 convert.ansi16.rgb = function (args) {
602 var color = args % 10;
605 if (color === 0 || color === 7) {
610 color = color / 10.5 * 255;
612 return [color, color, color];
615 var mult = (~~(args > 50) + 1) * 0.5;
616 var r = ((color & 1) * mult) * 255;
617 var g = (((color >> 1) & 1) * mult) * 255;
618 var b = (((color >> 2) & 1) * mult) * 255;
623 convert.ansi256.rgb = function (args) {
626 var c = (args - 232) * 10 + 8;
633 var r = Math.floor(args / 36) / 5 * 255;
634 var g = Math.floor((rem = args % 36) / 6) / 5 * 255;
635 var b = (rem % 6) / 5 * 255;
640 convert.rgb.hex = function (args) {
641 var integer = ((Math.round(args[0]) & 0xFF) << 16)
642 + ((Math.round(args[1]) & 0xFF) << 8)
643 + (Math.round(args[2]) & 0xFF);
645 var string = integer.toString(16).toUpperCase();
646 return '000000'.substring(string.length) + string;
649 convert.hex.rgb = function (args) {
650 var match = args.toString(16).match(/[a-f0-9]{6}|[a-f0-9]{3}/i);
655 var colorString = match[0];
657 if (match[0].length === 3) {
658 colorString = colorString.split('').map(function (char) {
663 var integer = parseInt(colorString, 16);
664 var r = (integer >> 16) & 0xFF;
665 var g = (integer >> 8) & 0xFF;
666 var b = integer & 0xFF;
671 convert.rgb.hcg = function (rgb) {
672 var r = rgb[0] / 255;
673 var g = rgb[1] / 255;
674 var b = rgb[2] / 255;
675 var max = Math.max(Math.max(r, g), b);
676 var min = Math.min(Math.min(r, g), b);
677 var chroma = (max - min);
682 grayscale = min / (1 - chroma);
691 hue = ((g - b) / chroma) % 6;
694 hue = 2 + (b - r) / chroma;
696 hue = 4 + (r - g) / chroma + 4;
702 return [hue * 360, chroma * 100, grayscale * 100];
705 convert.hsl.hcg = function (hsl) {
706 var s = hsl[1] / 100;
707 var l = hsl[2] / 100;
714 c = 2.0 * s * (1.0 - l);
718 f = (l - 0.5 * c) / (1.0 - c);
721 return [hsl[0], c * 100, f * 100];
724 convert.hsv.hcg = function (hsv) {
725 var s = hsv[1] / 100;
726 var v = hsv[2] / 100;
732 f = (v - c) / (1 - c);
735 return [hsv[0], c * 100, f * 100];
738 convert.hcg.rgb = function (hcg) {
739 var h = hcg[0] / 360;
740 var c = hcg[1] / 100;
741 var g = hcg[2] / 100;
744 return [g * 255, g * 255, g * 255];
747 var pure = [0, 0, 0];
748 var hi = (h % 1) * 6;
753 switch (Math.floor(hi)) {
755 pure[0] = 1; pure[1] = v; pure[2] = 0; break;
757 pure[0] = w; pure[1] = 1; pure[2] = 0; break;
759 pure[0] = 0; pure[1] = 1; pure[2] = v; break;
761 pure[0] = 0; pure[1] = w; pure[2] = 1; break;
763 pure[0] = v; pure[1] = 0; pure[2] = 1; break;
765 pure[0] = 1; pure[1] = 0; pure[2] = w;
771 (c * pure[0] + mg) * 255,
772 (c * pure[1] + mg) * 255,
773 (c * pure[2] + mg) * 255
777 convert.hcg.hsv = function (hcg) {
778 var c = hcg[1] / 100;
779 var g = hcg[2] / 100;
781 var v = c + g * (1.0 - c);
788 return [hcg[0], f * 100, v * 100];
791 convert.hcg.hsl = function (hcg) {
792 var c = hcg[1] / 100;
793 var g = hcg[2] / 100;
795 var l = g * (1.0 - c) + 0.5 * c;
798 if (l > 0.0 && l < 0.5) {
801 if (l >= 0.5 && l < 1.0) {
802 s = c / (2 * (1 - l));
805 return [hcg[0], s * 100, l * 100];
808 convert.hcg.hwb = function (hcg) {
809 var c = hcg[1] / 100;
810 var g = hcg[2] / 100;
811 var v = c + g * (1.0 - c);
812 return [hcg[0], (v - c) * 100, (1 - v) * 100];
815 convert.hwb.hcg = function (hwb) {
816 var w = hwb[1] / 100;
817 var b = hwb[2] / 100;
823 g = (v - c) / (1 - c);
826 return [hwb[0], c * 100, g * 100];
829 convert.apple.rgb = function (apple) {
830 return [(apple[0] / 65535) * 255, (apple[1] / 65535) * 255, (apple[2] / 65535) * 255];
833 convert.rgb.apple = function (rgb) {
834 return [(rgb[0] / 255) * 65535, (rgb[1] / 255) * 65535, (rgb[2] / 255) * 65535];
837 convert.gray.rgb = function (args) {
838 return [args[0] / 100 * 255, args[0] / 100 * 255, args[0] / 100 * 255];
841 convert.gray.hsl = convert.gray.hsv = function (args) {
842 return [0, 0, args[0]];
845 convert.gray.hwb = function (gray) {
846 return [0, 100, gray[0]];
849 convert.gray.cmyk = function (gray) {
850 return [0, 0, 0, gray[0]];
853 convert.gray.lab = function (gray) {
854 return [gray[0], 0, 0];
857 convert.gray.hex = function (gray) {
858 var val = Math.round(gray[0] / 100 * 255) & 0xFF;
859 var integer = (val << 16) + (val << 8) + val;
861 var string = integer.toString(16).toUpperCase();
862 return '000000'.substring(string.length) + string;
865 convert.rgb.gray = function (rgb) {
866 var val = (rgb[0] + rgb[1] + rgb[2]) / 3;
867 return [val / 255 * 100];