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From: jcb@lfcs.ed.ac.uk (Julian Bradfield)
Newsgroups: comp.windows.x
Subject: Painting through obscuring windows
Summary: When should it happen?
Message-ID: <432@etive.ed.ac.uk>
Date: 24 Jun 88 09:48:47 GMT
References: <1561@mrmarx.UUCP> <4639@mnetor.UUCP>
Sender: news@etive.ed.ac.uk
Reply-To: jcb@lfcs.ed.ac.uk (Julian Bradfield)
Organization: Laboratory for the Foundations of Computer Science, Edinburgh U
Lines: 11

I've just started using X (V10R4) for an application, and I used 
XBitmapBitsPut to paint a window. Since I only read the Xlib
documentation for XBitmapBitsPut at first, I didn't know that the
mask  could be given as zero to mean no mask, so I created an
all-ones bitmap to use as a mask. The result of this was that the
whole window was painted on the screen, including the bits that
were obscured by sibling windows. This surprised me, since I had
thought from what I read that one should be able to draw through
windows only with DrawThrough, and then only through your children.
Could somebody point me to the piece of documentation that I need to
reinterpret?  Thanks.