konva
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<p align="center"> <img src="https://raw.githubusercontent.com/konvajs/konvajs.github.io/master/apple-touch-icon-180x180.png" alt="Konva logo" height="180" /> </p>
26 lines (24 loc) • 629 B
JavaScript
(function() {
'use strict';
/**
* Grayscale Filter
* @function
* @memberof Konva.Filters
* @param {Object} imageData
* @example
* node.cache();
* node.filters([Konva.Filters.Grayscale]);
*/
Konva.Filters.Grayscale = function(imageData) {
var data = imageData.data, len = data.length, i, brightness;
for (i = 0; i < len; i += 4) {
brightness = 0.34 * data[i] + 0.5 * data[i + 1] + 0.16 * data[i + 2];
// red
data[i] = brightness;
// green
data[i + 1] = brightness;
// blue
data[i + 2] = brightness;
}
};
})();