code: function DropShadowFilter()
  {
      core.AbstractFilter.call(this);
  
      this.blurXFilter = new BlurXFilter();
      this.blurYTintFilter = new BlurYTintFilter();
  
      this.defaultFilter = new core.AbstractFilter();
  
      this.padding = 30;
  
      this._dirtyPosition = true;
      this._angle = 45 * Math.PI / 180;
      this._distance = 10;
      this.alpha = 0.75;
      this.hideObject = false;
      this.blendMode = core.BLEND_MODES.MULTIPLY;
  }
docs: The DropShadowFilter applies a Gaussian blur to an object.
  The strength of the blur can be set for x- and y-axis separately.
  
  @class
  @extends AbstractFilter
  @memberof PIXI.filters