Partial transparency in GDK?

[bratsche dfw net]

Can anyone give me some tips on how to display GdkPixmap images and stuff
that have partial transparency in them (loaded from png files and such),
so that the colors are properly blended with background colors and such?

In my particular situation, I'm wanting to display images over a
GtkDrawingArea, and I want the alpha pixels in the image to be properly
blended with the background style of the widget. Even if there is no color
or pixmap on the GtkDrawingArea, the image comes across as looking very
jagged and ugly.

Cody