Anti-aliasing via GPU

Kohei Yoshida kohei.yoshida at
Wed Dec 12 11:46:50 PST 2012

On 12/12/2012 12:53 PM, Thorsten Behrens wrote:
> Kohei Yoshida wrote:
>> I'm just wondering, whether our anti-aliasing is done strictly at software
>> level, or via hardware, and if former, what it would take to do it via
>> hardware so that we can take advantage of GPU to speed it up if it's there.
> On Linux, we use cairo, and XRender directly in vcl, so in theory that
> trapezoid rendering should be hw-accelerated. There were some
> unfortunate impedance mismatches though between cairo and gpu
> semantics, so at times this will fallback to software rendering.

Thanks for the info.  So, I'm guess this fallback happens inside cairo 
library?  IOW there isn't much we can do about it on the LibreOffice side?

My main concern was that, and the reason why I asked it was that when 
the anti-aliasing is enabled, the scrolling inside some quite complex 
Draw document becomes very very slow, and wondered if there was anything 
we could do about it.  When anti-alising is disabled, the scroll becomes 
smooth again.

Anyway, thanks a lot.  I'll sit on this.


Kohei Yoshida, LibreOffice hacker, Calc

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