gdk:window-shape-combine-region (window region xoffset yoffset)

window -- a gdk:window object
region -- a cairo:region-t region of window to be non-transparent
xoffset -- an integer with the x position of region in window coordinates
yoffset -- an integer with the y position of region in window coordinates

Makes pixels in the window outside region be transparent, so that the window may be nonrectangular. If region is nil, the shape will be unset, so the whole window will be opaque again. xoffset and yoffset are ignored if region is nil.

On the X11 platform, this uses an X server extension which is widely available on most common platforms, but not available on very old X servers, and occasionally the implementation will be buggy. On servers without the shape extension, this function will do nothing.

This function works on both toplevel and child windows.