Re: Hardware accelerated 2D graphics (with gtk-osx)

[Kristian Rietveld <kris gtk org>]

On Jul 27, 2010, at 10:49 AM, John Emmas wrote:
> Under Windows and Linux the (2D) scrolling display is smooth.  But under OS-X it's horribly jerky and has a 
> very 'klunky' look to it.  I happen to be viewing it on a Mac Mini but other people have seen the same 
> effect with more powerful machines.  It isn't a processor issue because even with my lowly Mac Mini, the 
> cpu usage rarely gets higher than about 30 percent.

On my Macs the GTK+ graphics rendering is pretty fast.  There might have been issues in the past, but recent 
GTK+ releases should be pretty good.

That said, some people do see performance issues that cannot be reproduced on other machines, for example 
https://bugzilla.gnome.org/show_bug.cgi?id=615917.  What exactly is causing this and whether this is 
hardware-specific still has to be found out.  We need to collect GTK+ version in use and hardware details in 
these cases.

> My guess is either that gtk-osx isn't using any technology that's compatible with Quartz Compositor - or if 
> it is, it's maybe using QuartzGL.  Disappointingly, QuartzGL DISABLES 2D hardware acceleration by default 
> and I'm wondering if this might explain the poor performance that we observe under OS-X?  As I said 
> earlier, Windows and Linux are both fine.

GTK+ OSX does all drawing using CoreGraphics, this should be hardware-accelerated whenever possible.


regards,

-kris.