public WindowsMutableGraphics(Microsoft.Graphics.Canvas.CanvasRenderTarget canvas)
     : base(canvas.CreateDrawingSession())
 {
     
     this.canvas = canvas;
     dispose();
 }
 public WindowsMutableGraphics(Microsoft.Graphics.Canvas.CanvasRenderTarget canvas)
     : base(canvas.CreateDrawingSession())
 {
     this.canvas = canvas;
     dispose();
 }