AWTTilePainter simply rounds the scaled double precision clipping rectangle to receive the integer rectangle. This leads to uncovered drawing areas, since the integer rectangle position could be greater - and the size could be smaller than the double precision source. To get the enclosing rectangle, we need to use iPos = floor(position) iSize = ceil(position+size) - floor(position) .. turns our that the double precision 'Rectangle Rectangle2D.getBounds()' already performs this math.