Subject:
Re: Multiple famebuffer
From:
Marc Nijdam ####@####.####
Date:
18 Nov 2000 03:06:20 -0000
Message-Id: <3A15F2C5.C89E5692@hp.com>
Jordan Crouse wrote:
>
> Well, you have to consider your resources. Adding a second device means
> that the kernel will have to load and manage a second framebuffer that
> won't even be seen. Thats a lot of fancy management for what just
> amounts to an extra block of memory somewhere.
Yeah, it's just that we save a blt from user to kernel space. Having two
fbs with hardware support to set the lcd memory start address makes
double buffering really fast, no?
> When you think of pixmap, its not a picture or something, its actually
> an fancy name for an offscreen window. After you create a pixmap, it
> acts as a window in every way. In fact, the GrNewPixmap() routine
> returns a GR_WINDOW_ID. Plus, when you are done, you can throw it away
> easily and quickly. There is really no better way to pull it off.
> Recently, we have ported XBill and XPenguins to Nano-X (when I get a
> chance, I will package up the source code and release it to this list),
> and we use GrPixmap double buffering heavily. I really think that is
> the easiest and fastest way to get things done.
Look forward to seeing this... Having two fbs saves some processing
overhead, which might be relevant on the hardware we're on. You think
it's not worth the effort?
Marc
>
> Marc Nijdam wrote:
> >
> > The way Kim (co-worker of mine) is set up now we're looking at having
> > multiple framebuffers fb0 and fb1, and would like to get microwindows
> > use those for double buffering. Is this harder? I guess not, since you
> > just wouldn't use GrPixmap() but the other fb device to build a
> > GR_WINDOW_ID instead?
> >
> > Cheers,
> >
> > Marc Nijdam
> >
> > Jordan Crouse wrote:
> > >
> > > Ok, now I understand whats going on. You want to double buffer your
> > > screen, not display to multiple framebuffers.
> > >
> > > Thats easy. Just use GrNewPixmap() to create a offscreen "window" that
> > > you can draw into, just like a real window. Then, when you're ready,
> > > use GrCopyArea to blit the pixmap area to the screen. For example, here
> > > I draw a rectangle in the pixmap and then put it on screen:
> > >
> > > GR_WINDOW_ID foo = GrNewPixmap(15, 15, NULL);
> > > GrSetGCForeground(gc, BLUE);
> > > GrFillRect(foo, gc, 5,5, 5, 5);
> > >
> > > GrCopyArea(GR_ROOT_WINDOW_ID, gc, 5, 5, 5, 5, foo, 0, 0, MW_SRCCOPY);
> > > GrDestroyWindow(foo);
> > >
> > > Hope that helps.
> > > Jordan
> > >
> > > "KIM,KYOUNG-IL (HP-Cupertino,ex1)" wrote:
> > > >
> > > > Thank you for advice.
> > > > My question is if Microwindows can use double(triple) framebuffers
> > > > and compare difference between buffers and update only difference
> > > > into dispay buffer. I know there was discussions and I don't know
> > > > how it gose now.
> > > >
> > > > Thank you,
> > > > Kyoung Kim
> > > >
> > > > -----Original Message-----
> > > > From: Alex Holden
> > > > To: KIM,KYOUNG-IL (HP-Cupertino,ex1)
> > > > Cc: ####@####.####
> > > > Sent: 11/16/00 1:30 AM
> > > > Subject: Re: Multiple famebuffer
> > > >
> > > > On Wed, 15 Nov 2000, KIM,KYOUNG-IL (HP-Cupertino,ex1) wrote:
> > > > > Can Microwindows(Win32 or Nono-X) handle multiple frame buffers ?
> > > >
> > > > Not currently. There was some talk recently of adding support for
> > > > multiple
> > > > displays; try searching the mailing list archive if you're interested
> > > > <http://www.linuxhacker.org/lists.phtml>
> > > >
> > > > --
> > > > ------- Alex Holden -------
> > > > http://www.linuxhacker.org/
> > > > http://www.robogeeks.org/
> > > >
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