private Surface(TGraphics graphics, string Filename)
{
_graphics = graphics;
if (!System.IO.File.Exists(Filename))
{
throw new System.IO.FileNotFoundException("The file could not be found!", Filename);
}
_target = (RenderTarget2D)RenderTarget2D.FromStream(graphics.GraphicsDevice, new FileStream(Filename, FileMode.Open));
Width = _target.Width;
Height = _target.Height;
}