it will render to a virtual image buffer just like it would to a window.
the logic works the exact same way as a window - it wil lonly render the rects
that changed. if a rect chnaged it expects that rect to have been cleared and
will blend the canvas ontop of the image - so you can use it to augment the
current image contents (though they will be permenantly modified). This is
specifically designed for doing things like rendering a canvas to be saved
to an image file.
WHEEEEEEEE :)
SVN revision: 3460
Carsten Haitzler