@:optionalalpha:Null<Int>
If provided, it will blend rectangles with averge color on top of resulting pixels, with given alpha.
@:optionalbitmap:Null<Bitmap>
@:optionalblend:Null<ColorBlend>
height:Int
@:optionaloutput:Null<Bitmap>
@:optionalregion:Null<Rectangle>
width:Int