I'm not surprised it doesn't look different. Masks don't have any effect on pixmaps.
I'm guessing (cos I'm not entirely sure what you are tryin to do), but I think you may need to draw the image using DrawImage instead of DrawPixmap, before you grab it using GrabPixmap.
I'm guessing (cos I'm not entirely sure what you are tryin to do), but I think you may need to draw the image using DrawImage instead of DrawPixmap, before you grab it using GrabPixmap.