Ximage's byte_order field

Jim Gettys jg at freedesktop.org
Wed Feb 25 10:46:35 PST 2009


You should be able to specify your byte order of the local image, and
Xlib worry about swapping for you, as I remember; but there will still
be a copy/swap taking someplace.

Sorry the API is so horrid: I got interrupted in the middle of designing
it for a meeting 2500 miles away, and the XImage interfaces never got
repaired....
                 Your dinosaur.
                    - Jim


On Wed, 2009-02-25 at 11:11 -0700, McDonald, Michael-p7438c wrote:
> 
> > -----Original Message-----
> > From: Pat Kane [mailto:pekane52 at gmail.com] 
> > Sent: Friday, February 20, 2009 1:02 PM
> > To: McDonald, Michael-p7438c
> > Subject: Re: Ximage's byte_order field
> > 
> > Mike,
> > 
> > How is your frame buffer connected to your little endian machine?
> 
>   It's a shared memory area generated by a COTS software package. As
> such, we can't modify its byte-order. There may be multiple copies of
> this package running at the same time, each with its own "virtual
> framebuffer". We want to display all of these vfbs on a real display
> that's running X with the Intel driver. 
> 
> Brute force copying the vfbs using XPutImage() is the only method we've
> come up with for displaying the vfbs. But that required us to make a
> copy of the source vfbs with the byte-order fixed. By setting the
> byte_order field of the _Ximage structure, we hope we can eliminate the
> intermediate copy of the vfbs.
> 
> Mike McDonald
> GDC4S/FCS/PVM/SDC 
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-- 
Jim Gettys <jg at freedesktop.org>




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