Add Image overlay to ESRI Map in FLEX

Adding an image overlay to an ESRI Map in Flex is not really a default functionality. So when a project came along that required one I wrote this. There does seem to be a size limitation for the image you are trying to load. I did not really have a chance to explore the issue, but it worked when the image width was under 2500 pixels wide.

package com.cinque_fiori.mapping.symbols
{
 import com.esri.ags.Graphic;
 import com.esri.ags.Map;
 import com.esri.ags.esri_internal;
 import com.esri.ags.geometry.MapPoint;
 import com.esri.ags.symbol.Symbol;
 
 import flash.display.BitmapData;
 import flash.geom.Matrix;

 use namespace esri_internal;
 


 public class BitmapMarkerSymbol extends Symbol
 {
  
  private var _bitmap:BitmapData;
  private var _lowerLeft:MapPoint;
  private var _visible:Boolean;

  public function BitmapMarkerSymbol ()
  {
   super();
   this._lowerLeft = new MapPoint();
   this._bitmap;
   this._visible = true;
  }


  override esri_internal function drawGraphic( map : Map, graphic : Graphic ): void
  {
   if( graphic.geometry is MapPoint ) {
    drawBitmapOnMap( map, graphic, MapPoint( graphic.geometry ));
   }
  }


  private function drawBitmapOnMap( map : Map, graphic:Graphic,mapPoint:MapPoint ): void {
   if( this._lowerLeft != null && this._bitmap != null ){
    graphic.x = map.mapToContainerX(mapPoint.x);
    graphic.y = map.mapToContainerY(mapPoint.y);

    var w:Number = map.mapToContainerX(this._lowerLeft.x) - graphic.x;
    var h:Number = map.mapToContainerY(this._lowerLeft.y) - graphic.y;
    var m:Matrix = new Matrix(w/this._bitmap.width,0,0,h/this._bitmap.height,0,0);

    graphic.graphics.clear();
    if(this._visible){
     graphic.graphics.beginBitmapFill( this._bitmap, m , false , true );
     graphic.graphics.drawRect(0,0,w,h);
     graphic.graphics.endFill();
    }
   }
  }

  public function get lowerLeft() : MapPoint{
   return this._lowerLeft;
  }

  public function set lowerLeft( pt:MapPoint ) : void{
   this._lowerLeft = pt;
  }

  public function get bitmap() : BitmapData{
   return this._bitmap;
  }

  public function set bitmap( bitmapData:BitmapData ) : void{
   this._bitmap = bitmapData;
  }
  
  public function get visible() : Boolean{
   return this._visible; 
  }
  
  public function set visible( visible:Boolean ) : void{
   this._visible = visible;
  }
 }
}