konva/src/filters/Brighten.js

<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>

(function(Konva) {
  'use strict';
  /**
     * Brighten Filter.
     * @function
     * @memberof Konva.Filters
     * @param {Object} imageData
     * @example
     * node.cache();
     * node.filters([Konva.Filters.Brighten]);
     * node.brightness(0.8);
     */
  Konva.Filters.Brighten = function(imageData) {
    var brightness = this.brightness() * 255,
      data = imageData.data,
      len = data.length,
      i;

    for (i = 0; i < len; i += 4) {
      // red
      data[i] += brightness;
      // green
      data[i + 1] += brightness;
      // blue
      data[i + 2] += brightness;
    }
  };

  Konva.Factory.addGetterSetter(
    Konva.Node,
    'brightness',
    0,
    null,
    Konva.Factory.afterSetFilter
  );
  /**
    * get/set filter brightness.  The brightness is a number between -1 and 1.&nbsp; Positive values
    *  brighten the pixels and negative values darken them. Use with {@link Konva.Filters.Brighten} filter.
    * @name brightness
    * @method
    * @memberof Konva.Node.prototype
    * @param {Number} brightness value between -1 and 1
    * @returns {Number}
    */
})(Konva);