Shadowing icons

[Miguel de Icaza <miguel nuclecu unam mx>]

Hello guys,

   I would like to make our Icon List nicer and I was thinking that
instead of drawing a blue box behind the icon and then drwaing the
icon on top of that, we should be able to draw some sort of shadow
that would highlight the icon.

   What I would like to have is to just extend the icon mask, compute
the diference and draw on the difference a color.  Optimally, I would
like to use shades of colors:  The closer the pixel is to the original
mask, the brigther.

   Anyone wants to volunteer to write such a routine?

Miguel.