initialize(options) {
      if (!options) {
        options = {};
      }
      this.color = options.color || '#FFFFFF';
      this.threshold = options.threshold || 45;
      this.x = options.x || null;
      this.y = options.y || null;
    }
Constructor
@member fabric.Image.filters.ColorFilter.prototype
@param {Object} [options] Options object
@param {Number} [options.color='#FFFFFF'] Value of color (0...255)
@param {Number} [options.threshold=45] Value of threshold (0...255)
@override