package
  {
          import flash.display.Sprite;
          import flash.display.Bitmap;
          import flash.display.BitmapData;
          import flash.events.MouseEvent;
          import flash.events.Event;
          import flash.filters.BlurFilter;
          
          public class @ax-animation-ch04-SprayPaint extends Sprite
          {
                  private var canvas:BitmapData;
                  private var color:uint;
                  private var size:Number = 50;
                  private var density:Number = 50;
                  
                  public function @ax-animation-ch04-SprayPaint()
                  {
                          init();
                  }
                  
                  private function init():void
                  {
                          canvas = new BitmapData(stage.stageWidth, stage.stageHeight, true, 0x00000000);
                          var bmp:Bitmap = new Bitmap(canvas);
                          bmp.filters = [new BlurFilter(2, 2, 3)];
                          addChild(bmp);
                          
                          stage.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
                          stage.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
                  }
                  
                  private function onMouseDown(event:MouseEvent):void
                  {
                          color = Math.random() * 0xffffff + 0xff000000;
                          addEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
  
                  private function onMouseUp(event:MouseEvent):void
                  {
                          removeEventListener(Event.ENTER_FRAME, onEnterFrame);
                  }
  
                  private function onEnterFrame(event:Event):void
                  {
                          for(var i:int = 0; i < density; i++)
                          {
                                  var angle:Number = Math.random() * Math.PI * 2;
                                  var radius:Number = Math.random() * size;
                                  var xpos:Number = mouseX + Math.cos(angle) * radius;
                                  var ypos:Number = mouseY + Math.sin(angle) * radius;
                                  canvas.setPixel32(xpos, ypos, color);
                          }
                  }
          }
  }