57 lines
1.6 KiB
JavaScript
57 lines
1.6 KiB
JavaScript
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/**
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* rgb2hex
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*
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* @author Christian Bromann <mail@christian-bromann.com>
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* @description converts rgba color to HEX
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*
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* @param {String} color rgb or rgba color
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* @return {Object} object with hex and alpha value
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*/
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var rgb2hex = module.exports = function rgb2hex(color) {
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if(typeof color !== 'string') {
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// throw error of input isn't typeof string
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throw new Error('color has to be type of `string`');
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} else if (color.substr(0, 1) === '#') {
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// or return if already rgb color
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return {
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hex: color,
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alpha: 1
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};
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}
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/**
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* strip spaces
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*/
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var strippedColor = color.replace(/\s+/g,'');
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/**
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* parse input
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*/
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var digits = /(.*?)rgb(a)??\((\d{1,3}),(\d{1,3}),(\d{1,3})(,([01]|1.0*|0??\.([0-9]{0,})))??\)/.exec(strippedColor);
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if(!digits) {
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// or throw error if input isn't a valid rgb(a) color
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throw new Error('given color (' + color + ') isn\'t a valid rgb or rgba color');
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}
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var red = parseInt(digits[3], 10);
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var green = parseInt(digits[4], 10);
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var blue = parseInt(digits[5], 10);
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var alpha = digits[6] ? /([0-9\.]+)/.exec(digits[6])[0] : '1';
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var rgb = ((blue | green << 8 | red << 16) | 1 << 24).toString(16).slice(1);
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// parse alpha value into float
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if(alpha.substr(0,1) === '.') {
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alpha = parseFloat('0' + alpha);
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}
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// cut alpha value after 2 digits after comma
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alpha = parseFloat(Math.round(alpha * 100)) / 100;
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return {
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hex: '#' + rgb.toString(16),
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alpha: alpha
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};
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};
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