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From: mouse@LARRY.MCRCIM.MCGILL.EDU
Newsgroups: comp.windows.x
Subject: Re:  Bitmap -> Pixmap operation
Message-ID: <9008100624.AA26553@Larry.McRCIM.McGill.EDU>
Date: 10 Aug 90 06:24:56 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 37

> I have a Bitmap (single plane Pixmap) and an eight plane Pixmap.  I
> want to stamp the Bitmap onto the Pixmap so that any off locations in
> the Bitmap don't change the Pixmap and any on locations in the Bitmap
> set that location in the Pixmap to a specific value (i.e. 254).  Is
> there an easy X way to do this?

Create a GC appropriate to the 8-plane pixmap; set its components as
follows:

	stipple = the bitmap
	fill-style = FillStippled
	foreground = 254 (or whatever the specific value is)

Then use XFillRectangle to fill the whole pixmap with this GC.  (I
assume the origins are to be identified with one another; if this is
not true you need to set the tile/stipple origin in the GC.)

Alternatively, set

	clip-mask = the bitmap
	fill-style = FillSolid
	foreground = 254

Then use XFillRectangle just as before.

Which is more efficient?  I don't know; it depends on your server.  The
semantics are the same only under certain circumstances which I don't
feel up to working out in all their gory detail.  But if no part of the
pixmap extends outside the bitmap, the semantics are identical, at
least as far as I understand them.  (One obvious semantic difference is
that if the bitmap is smaller than the pixmap, the first method given
replicates it; the second doesn't.)

					der Mouse

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