Makes pixels in this outside
shape_region be transparent, so that the window may be
shape_region is null, the shape will be unset, so the whole window will be opaque again.
offset_y are ignored if
shape_region is null.
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.
region of window to be non-transparent
X position of
Y position of