29 lines
735 B
JavaScript
29 lines
735 B
JavaScript
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var utils = require('../utils');
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/**
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* Adjust HSL `color` `prop` by `amount`.
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*
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* @param {RGBA|HSLA} color
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* @param {String} prop
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* @param {Unit} amount
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* @return {RGBA}
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* @api private
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*/
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module.exports = function adjust(color, prop, amount){
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utils.assertColor(color, 'color');
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utils.assertString(prop, 'prop');
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utils.assertType(amount, 'unit', 'amount');
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var hsl = color.hsla.clone();
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prop = { hue: 'h', saturation: 's', lightness: 'l' }[prop.string];
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if (!prop) throw new Error('invalid adjustment property');
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var val = amount.val;
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if ('%' == amount.type){
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val = 'l' == prop && val > 0
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? (100 - hsl[prop]) * val / 100
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: hsl[prop] * (val / 100);
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}
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hsl[prop] += val;
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return hsl.rgba;
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};
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