[cairo] Bug in _cairo_xlib_surface_create_similar

[Jim Gettys]

The Nvidia closed source driver doesn't use XAA.

Something else stinks.
			- Jim


On Mon, 2006-02-20 at 17:03 -0500, Owen Taylor wrote:
> On Tue, 2006-02-21 at 10:26 +1300, Robert O'Callahan wrote:
> > I recently discovered that cairo_create_similar on a 16-bit xlib surface
> > creates a surface backed by a 24-bit pixmap. This results in absymal
> > performance --- I can actually watch a copy from the similar to the
> > original move down the screen, on my dual Xeon, NVidia vendor driver
> > machine. It also means xlib-based code like GTK themes can't render to
> > the surface because it doesn't match the screen depth.
> > 
> > The attached patch makes _cairo_xlib_surface_create_similar match the
> > characteristics of the input surface as closely as I know how, and fixes
> > my issues. Please evaluate...
> 
> No real opinion on the patch, one way or the other. Strong opinion
> that you need to file a bug with NVidia; even if they can't accelerate
> drawing to the surface (limitations of XAA), they definitely should
> be able to copy to the screen with high performance.
> 
> Well, actually one opinion on the patch, from a quick glance.
> It's very much wrong to create an image surface when you can't
> create a surface with matching depth... let the X server decide
> it can't accelerate that.
> 
> 						Owen
> 
> 
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