mirror of https://github.com/zulip/zulip.git
58 lines
1.6 KiB
JavaScript
58 lines
1.6 KiB
JavaScript
var colorspace = (function () {
|
|
|
|
var exports = {};
|
|
|
|
// Convert an sRGB value in [0, 255] to a linear intensity
|
|
// value in [0, 1].
|
|
//
|
|
// http://en.wikipedia.org/wiki/SRGB#The_reverse_transformation
|
|
exports.sRGB_to_linear = function (v) {
|
|
v = v / 255.0;
|
|
if (v <= 0.04045) {
|
|
return v / 12.92;
|
|
}
|
|
return Math.pow((v + 0.055) / 1.055, 2.4);
|
|
};
|
|
|
|
// Compute luminance (CIE Y stimulus) from linear intensity
|
|
// of sRGB / Rec. 709 primaries.
|
|
exports.rgb_luminance = function (channel) {
|
|
return 0.2126*channel[0] + 0.7152*channel[1] + 0.0722*channel[2];
|
|
};
|
|
|
|
// Convert luminance (photometric, CIE Y)
|
|
// to lightness (perceptual, CIE L*)
|
|
//
|
|
// http://en.wikipedia.org/wiki/Lab_color_space#Forward_transformation
|
|
exports.luminance_to_lightness = function (luminance) {
|
|
var v;
|
|
if (luminance <= (216 / 24389)) {
|
|
v = (841 / 108)*luminance + (4 / 29);
|
|
} else {
|
|
v = Math.pow(luminance, 1/3);
|
|
}
|
|
|
|
return 116*v - 16;
|
|
};
|
|
|
|
exports.getDecimalColor = function (hexcolor) {
|
|
return {r: parseInt(hexcolor.substr(1,2), 16),
|
|
g: parseInt(hexcolor.substr(3,2), 16),
|
|
b: parseInt(hexcolor.substr(5,2), 16)};
|
|
};
|
|
|
|
exports.getLighterColor = function (rgb, lightness) {
|
|
return {r: (lightness * 255 + (1 - lightness) * rgb.r).toFixed(),
|
|
g: (lightness * 255 + (1 - lightness) * rgb.g).toFixed(),
|
|
b: (lightness * 255 + (1 - lightness) * rgb.b).toFixed()};
|
|
};
|
|
|
|
exports.getHexColor = function (rgb) {
|
|
return "#" + parseInt(rgb.r, 10).toString(16) +
|
|
parseInt(rgb.g, 10).toString(16) +
|
|
parseInt(rgb.b, 10).toString(16);
|
|
};
|
|
|
|
return exports;
|
|
}());
|