nanogui: Patch for Shared Memory Pixmaps
Subject:
Re: [nanogui] Re: Patch for Shared Memory Pixmaps
From:
David Eger ####@####.####
Date:
14 Aug 2001 15:21:19 -0000
Message-Id: <Pine.LNX.4.33.0108141016190.295-100000@su13.eastnet.gatech.edu>
I have used this patch, and it has worked. But then, there are a couple
of caveats; you will have to change some code.
(1) The passed parameter is no longer a pointer. It is a shmid. Pointers
will not work. So you need to actually do System V memory calls in your
user code to get a new Sys V ShM area and use it.
(2) If you are NOT using ShM Pixmaps, then yes, you need to change the
third argument of GrNewPixmap from 0 to -1. Yes, it's a pain. Yes, I see
your point.
(2) The pixmap currently MUST be the same bit depth as the framebuffer.
Other than that, it should be golden. If you have problems, let me know.
-David
On Tue, 14 Aug 2001, Jordan Crouse wrote:
> So what happens if I compile this patch into one of my existing programs and
> run it as is? (I am famous for using lots of pixmaps).. Will it crash, or
> will it work as advertised?
>
> Jordan
>
> On Monday 13 August 2001 23:41, David T Eger mentioned:
> > Sorry about the wait. Been busy cleaning up a Framebuffer driver.
> > Here's the patch. I haven't differentiated GrNewPixmap() into separate
> > functions (as Jordan suggested) from the standard code for several
> > reasons:
> >
> > (1) If we really do link statically and pass a pointer, then isn't the
> > client/server X model sort of misplaced?
> > (2) 0 is not an invalid SHM key, however -1 is an invalid SHM key, and
> > also an invalid pointer. We will never have a one byte pixmap at the end
> > of memory
> > (3) I'm too lazy to rewrite it right now.
> >
> > -David Eger
> >
[ snip ]
