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From: welter@ils.nwu.edu (Pete Welter)
Newsgroups: comp.windows.ms.programmer
Subject: BitBlt question
Keywords: ms-windows bitmap
Message-ID: <703@anaxagoras.ils.nwu.edu>
Date: 22 Jan 91 21:21:08 GMT
Sender: news@ils.nwu.edu
Distribution: usa
Organization: Institute for the Learning Sciences
Lines: 17

I am trying to display a large colored bitmap using BitBlt.
When the bitmap is drawn, it appears rather slowly in a series
of (about 4 or 5) horizontal swipes.  I have noticed the same
behavior when zooming out on this same image using MS-Paint;
seemingly the use of StretchBlt rather than BitBlt is causing this.
When the image is at normal size is MS-Paint, the drawing seems
pretty fast.

My question is: Is there any reason why BitBlt would redraw in
these horizontal strips?

Thanks!

Pete Welter
Institute for the Learning Sciences
Northwestern University
welter@ils.nwu.edu