Re: [Qemu-devel] QEMU GUI

["Kevin F. Quinn" <ml@kevquinn.com>]

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On Thu, 22 Jun 2006 20:53:54 -0500
Anthony Liguori <aliguori@us.ibm.com> wrote:

> Kevin F. Quinn wrote:
> > Part of that should be to determine what the GUI will actually do;
> 
> You're getting ahead of yourself.  Just getting qemu to start with 
> wxWidgets instead of SDL would be a big step in the right direction.
> 
> > At this point you're talking about embedding the Qemu guest window
> > directly into the wxWidgets GUI, yes?  I'm thinking the primitives
> > that the graphics driver in QEMU is emulating are not at the GL
> > level, but at the raw hardware level - I don't know how far apart
> > these things are, but I'd hazard that a GL canvas won't really help.
> >   
> 
> QEMU doesn't expose any real 2d acceleration to the drawing
> routines. Using GL canvas would be interesting though as you'd get
> hardware scaling with interpolation.  That's a big performance win.

And scaling the guest window would be really useful...

> > I do think the ability to pass through accelerated graphics stuff
> > from the guest to the host should be a big factor.  I assume this
> > is what the cirrus emulation currently does through SDL, to some
> > extent at least. This issue would make or break guest graphics
> > performance. 
> 
> Nope, currently SDL is used as one big bitmap viewer.
> 
> > I'm ignorant of details, but from a vague hand-wavy distance it
> > should be simple enough to retain SDL for the emulation windows
> > (and SDL does seem to be the tool for the job there), with a
> > separate wxWidgets 
> 
> Bleh, why would you say that?  SDL is pretty crappy on X.  It's just
> a wrapper around XShmImage.  You can access the same thing via GTK or
> any other reasonable toolkit.

Ok; my ignorance is shining through :)  I thought SDL did a lot more
than that.

> SDL is mostly useful because of the number of backend drivers that it 
> supports.

Had a rummage through the wxWidgets code. It uses SDL for sound support
(or can do so, at any rate) but not for video.  With the GTK backend you
get an XShm image if XShm is supported (wxGTK asks GTK for
GDK_IMAGE_FASTEST). I don't find any references to XShm in the x11
backend, so I guess the raw X11 backend doesn't use it.  On X you'd
normally go for the GTK backend anyway.

> Regards,
> 
> Anthony Liguori
> 
> > frontend GUI to manage the launch and visibility of emulation
> > windows, assist in guest creation etc.
> >
> > Perhaps it's worth asking the WxWidgets people what they might
> > suggest.
> >
> >   
> >> Regards,
> >>
> >> Anthony Liguori
> >>
> >>     
> >>> If someone is interested, I am ready to try to include such a GUI
> >>> in the QEMU repository even if it is not usable yet.
> >>>
> >>> Regards,
> >>>
> >>> Fabrice.

-- 
Kevin F. Quinn

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