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From: shamash@cs.columbia.edu (Ari Shamash)
Newsgroups: comp.windows.x
Subject: bug in mfb routines??
Summary: mfb routines don't work with 720 pixel width frame buffer..
Message-ID: <1991Jan29.200122.20143@cs.columbia.edu>
Date: 29 Jan 91 20:01:22 GMT
Sender: news@cs.columbia.edu (The Daily News)
Reply-To: shamash@cs.columbia.edu (Ari Shamash)
Distribution: usa
Organization: Columbia University Computer Science Dept
Lines: 33

I'm having trouble using the mfb routines with a 720x280 bitmap
display.  There seems to be some kind of step function associated with
the width.  What seems to be happening is that the routines assume
that I meant 768x280, so the resulting graphics are skewed to the
right (as if the horizontal control on the display needs to be
adjusted).

The skewed pattern remains on the screen if the width is lowered to
705, but changes to the left when the width is set to 704.  704 and
705 are the half-way points between 640 and 768 (two standard
framebuffer sizes).  So, when I specified 720 as the width, it got
stepped up to 768...

Can anybody point me as to where in the mfb code this is being done?
I'm using X11R4 plus all the patches..

Thanks,
Ari

P.S. if this makes a difference, this is how I initialize the mfb
routines..

  mfbScreenInit(pScreen,
		screen_addr+display_info[display_type].display_offset,
		720,		/* width */
		280,            /* height */
		75, 		/* resolution/inches */
		75, 		/* resolution/inches */
 		720);           /* actual framebuffer width */

--
shamash@cs.columbia.edu
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