[Last modified: Dec 98]

Answer: The simplest way is probably to use the SHAPE protocol extension.  The
xeyes, xlogo, and oclock demo programs in X11R5 (and later) are good examples
of using SHAPE with widgets. You should be able to use the same techniques
with your Motif widget subclasses.

Ken Lee

Ken Sall (ksall@cen.com) adds: The official name for this extension is "X11
Nonrectangular Window Shape Extension". If you have X11R5 source, the Shape
extension document is $TOP/mit/hardcopy/extensions/shape.PS or
$TOP/mit/doc/extensions/shape.ms. In X11R6, see
$TOP/xc/doc/hardcopy/Xext/shape.PS or $TOP/xc/doc/specs/Xext/shape.ms.  There
is also a terse man page: $TOP/mit/man/Xext/XShape.man (X11R5) and
$TOP/xc/doc/man/Xext/XShape.man (X11R6).

Ken Lee adds:  Some graphics-oriented systems (e.g., SGI, HP) include hardware
overlay planes that support transparency directly.  The APIs for accessing
these capabilities from Motif programs are non-standard.  Read your system's
documentation or contact your vendor for more details.