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37 lines
896 B
37 lines
896 B
var utils = require('../utils') |
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, nodes = require('../nodes'); |
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/** |
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* Blend the `top` color over the `bottom` |
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* |
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* Examples: |
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* |
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* blend(rgba(#FFF, 0.5), #000) |
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* // => #808080 |
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* |
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* blend(rgba(#FFDE00,.42), #19C261) |
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* // => #7ace38 |
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* |
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* blend(rgba(lime, 0.5), rgba(red, 0.25)) |
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* // => rgba(128,128,0,0.625) |
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* |
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* @param {RGBA|HSLA} top |
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* @param {RGBA|HSLA} [bottom=#fff] |
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* @return {RGBA} |
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* @api public |
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*/ |
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module.exports = function blend(top, bottom){ |
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// TODO: different blend modes like overlay etc. |
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utils.assertColor(top); |
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top = top.rgba; |
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bottom = bottom || new nodes.RGBA(255, 255, 255, 1); |
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utils.assertColor(bottom); |
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bottom = bottom.rgba; |
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return new nodes.RGBA( |
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top.r * top.a + bottom.r * (1 - top.a), |
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top.g * top.a + bottom.g * (1 - top.a), |
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top.b * top.a + bottom.b * (1 - top.a), |
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top.a + bottom.a - top.a * bottom.a); |
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};
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