getting bitmap masks for rc-specified pixmaps

[Paul Barton-Davis <pbd Op Net>]

i just figured out how to do "shaped" windows c/o the testgtk demo of
the same.

but i have a problem. i'd like to be able to use a gtkrc file to let
users specify the pixmaps they want for various visual
elements. however, the style that is generated from the rc file only
contains the pixmaps, not the masks. this means that i can't use the
pixmaps to generate a shaped image.

i'd like to suggest one of two changes: 

    1) either add a "fg_pixmap" specifier for rc files, and 
       have this also generate and make available the mask

    2) make the mask available for background pixmaps.

obviously, a widget will have to still draw the pixmap itself, using
gtk_widget_shape_combine_mask() to get the shape effect, but the rc
file provides a very convenient and standard way to specify which
pixmap should be used for a given widget state.

--p