Image.XWD.decode doesn't handle XY (bitplane) images
Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=2315
Reported by @marcus
If an XY format window dump is given to Image.XWD.decode(), it just returns 0.
kronan:~% xwd -xy >/tmp/grab.xwd
kronan:~%
pike Pike
v7.2 release 144 running Hilfe v2.0 (Incremental Pike Frontend)
> Image.XWD.decode(Stdio.read_file("/tmp/grab.xwd"));
Result: 0
>