You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
38 lines
896 B
38 lines
896 B
9 years ago
|
var utils = require('../utils')
|
||
|
|
, nodes = require('../nodes');
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Blend the `top` color over the `bottom`
|
||
|
|
*
|
||
|
|
* Examples:
|
||
|
|
*
|
||
|
|
* blend(rgba(#FFF, 0.5), #000)
|
||
|
|
* // => #808080
|
||
|
|
*
|
||
|
|
* blend(rgba(#FFDE00,.42), #19C261)
|
||
|
|
* // => #7ace38
|
||
|
|
*
|
||
|
|
* blend(rgba(lime, 0.5), rgba(red, 0.25))
|
||
|
|
* // => rgba(128,128,0,0.625)
|
||
|
|
*
|
||
|
|
* @param {RGBA|HSLA} top
|
||
|
|
* @param {RGBA|HSLA} [bottom=#fff]
|
||
|
|
* @return {RGBA}
|
||
|
|
* @api public
|
||
|
|
*/
|
||
|
|
|
||
|
|
module.exports = function blend(top, bottom){
|
||
|
|
// TODO: different blend modes like overlay etc.
|
||
|
|
utils.assertColor(top);
|
||
|
|
top = top.rgba;
|
||
|
|
bottom = bottom || new nodes.RGBA(255, 255, 255, 1);
|
||
|
|
utils.assertColor(bottom);
|
||
|
|
bottom = bottom.rgba;
|
||
|
|
|
||
|
|
return new nodes.RGBA(
|
||
|
|
top.r * top.a + bottom.r * (1 - top.a),
|
||
|
|
top.g * top.a + bottom.g * (1 - top.a),
|
||
|
|
top.b * top.a + bottom.b * (1 - top.a),
|
||
|
|
top.a + bottom.a - top.a * bottom.a);
|
||
|
|
};
|