Re: [Qemu-devel] [patch] cocoa.m - Core Graphics support

[Julian Seward <jseward@acm.org>]

On Thursday 31 January 2008 10:46, Jamie Lokier wrote:
> Anthony Liguori wrote:
> > VGA framebuffer operations come in as memory operations.  They're
> > tracked by watching what memory gets dirtied.  This can only operate at
> > a page-granularity so this results in scan-line granularity updates.
> > The VNC front-end goes to great lengths to keep a shadowed framebuffer
> > and reduce these updates to a smaller update region.  You could possibly
> > look at refactoring that code.  However...
>
> That update region code should probably be moved to something generic
> and made into a generic display option.
>
> Reducing update region is logically orthogonal, and could work with
> any update method (e.g. local X11, remote X11, local X11-OpenGL,
> remote X11-OpenGL, SDL etc.).  With some of those, for some people
> (especially some but not all remote setups) it might be worth it.

For exactly these reasons I developed a shadow framebuffer patch
which ...

> makes QEMU's graphics emulation much more usable over remote
> X connections, by reducing the amount of data sent to the X server.
> This is particularly noticeable for small display updates, most
> importantly mouse cursor movements, which become faster and so 
> generally make the guest's GUI more pleasant to use.

See
http://lists.gnu.org/archive/html/qemu-devel/2007-03/msg00141.html
for the patch and short associated thread.  It never got included,
though.

J