package{
   
    import flash.display.Sprite;
    import flash.events.MouseEvent;
    import flash.display.BitmapData;
    import flash.display.Bitmap;
    import flash.display.GradientType;
    import flash.display.SpreadMethod;
    import flash.display.Shape;
    import flash.geom.Matrix;
    import flash.utils.setInterval;
    import flash.utils.clearInterval;
   
    public class BitmapErase extends Sprite {
       
        private var md:Boolean = false;
        private var event_spr:Sprite;
        private var area_width:Number;
        private var area_height:Number;
        private var fillType:String = GradientType.LINEAR;
        private var colors:Array = [0xFF0000, 0x00FF00, 0x0000ff];
        private var alphas:Array = [1, 1, 1];
        private var ratios:Array = [0, 128, 255];
        private var spreadMethod:String = SpreadMethod.PAD;
        private var matrix:Matrix = new Matrix();
        private var erase_shape:Shape;
        private var draw_shape:Shape;
        private var bmpd:BitmapData;
        private var bmp:Bitmap;
        private var interval:uint;
       
        public function BitmapErase(){
            draw_shape = new Shape();
            addChild (draw_shape);
            erase_shape = new Shape();
            event_spr = new Sprite();
            addChild (event_spr);
            area_width = event_spr.stage.stageWidth;
            area_height = event_spr.stage.stageHeight-32;
            matrix.createGradientBox (area_width, area_height, 1, 0, 0);
           
            event_spr.graphics.beginGradientFill (fillType,colors,alphas,ratios,matrix,spreadMethod);
            event_spr.graphics.drawRect (0,0,area_width, area_height);
            event_spr.graphics.endFill ();
       
            event_spr.addEventListener (MouseEvent.MOUSE_DOWN, _onMouseDown);
            event_spr.addEventListener (MouseEvent.MOUSE_MOVE, _onMouseMove);
            event_spr.addEventListener (MouseEvent.MOUSE_UP, _onMouseUp);
            event_spr.addEventListener (MouseEvent.MOUSE_OUT, _onMouseUp);
           
            bmpd = new BitmapData(event_spr.width,event_spr.height,true,0);
            bmp = new Bitmap(bmpd);
            addChild (bmp);
        }

        private function _onMouseDown (e:MouseEvent):void {
            //debug ("_onMouseDown");
            draw_shape.graphics.lineStyle (10, 0xffffff, 1);
            erase_shape.graphics.lineStyle (20, 0xffffff, 1);
            draw_shape.graphics.moveTo (e.localX,e.localY);
            erase_shape.graphics.moveTo (e.localX,e.localY);
            md = true;
        }
        private function _onMouseUp (e:MouseEvent):void {
            md = false;
            draw_shape.graphics.clear ();
            erase_shape.graphics.clear ();
            clearInterval(interval);
        }
        private function _onMouseMove (e:MouseEvent):void {
            //debug ("_onMouseMove");
            if (md && !e.ctrlKey) {
                draw_shape.graphics.lineTo (e.localX,e.localY);
                interval = setInterval(drawNow,1);
            } else if (md && e.ctrlKey) {
                erase_shape.graphics.lineTo (e.localX,e.localY);
                bmp.bitmapData.draw (erase_shape,null,null,"erase");
            }
        }
        private function debug (v:String):void {
            var d:Date = new Date();
            trace (d.getMinutes()+":"+d.getSeconds()+":"+d.getMilliseconds()+": "+v);
        }
        private function drawNow():void{
            bmp.bitmapData.draw (draw_shape);
        }
    }
}