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.