Re: [OT] Quartz Extreme in developer previews?
Re: [OT] Quartz Extreme in developer previews?
- Subject: Re: [OT] Quartz Extreme in developer previews?
- From: Pierre-Olivier Latour <email@hidden>
- Date: Sat, 13 Jul 2002 18:36:50 +0200
>
One suggested that Quartz Extreme would store off screen bitmaps in the
>
graphics memory, so that the blitter could be use for all these trivial
>
clear, copy and compose functions that make up most layer operations --
>
which should make the speed of Quartz closer to the 2.1 GB/s that my
>
GeForce claims to offer in bandwidth.
That's a common misconception about Quartz Extreme (btw Apple has some
responsibility in it by not saying clearly what QE is).
Do not forget that all Quartz operations are done in software by the CPU
(bezier drawing, font drawing, etc...). Quartz Extreme _only_ helps in
window compositing (according to Apple's own definition), which will be done
by the graphic card instead of the CPU as in today's OS X.
Therefore, QE won't speed up quartz drawing inside the window, nor help
window resizing and so on.
The main difference is that dragging a window onscreen consumes up to 80%
processing power today (even on my 800MP). With QE, the graphic card will do
the computations (thanks to window content being available as textures), and
it will consume extremely few processing power. You can also have
transparency in windows or aliasing for Aqua effects without any penalty.
FYI: copy, clear and copy with scaling operations from RAM to VRAM are
hardware accelerated in the current OS X versions. Otherwise it would be
slow as hell.
_____________________________________________________________
Pierre-Olivier Latour email@hidden
Lausanne, Switzerland
http://www.pol-online.net
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