[cairo] [Pixman] Floating point API in Pixman
sandmann at daimi.au.dk
Mon Aug 16 23:42:12 PDT 2010
Krzysztof Kosiński <tweenk.pl at gmail.com> writes:
> So what is the bottom line? Should we have two versions of all code,
> one using float and one using pixman_fixed_t, or is replacing
> pixman_fixed_t with float sufficient?
As far as I am concerned, using floating point is fine. I have not
heard otherwise from anybody who has done any kind of real work on the
pixman ARM backends.
> How much slower is softfloat - a factor of 5, 15 or 500?
I don't know the number, but it's likely true that if you hit
softfloat at any regularity, the software becomes too slow to be
usable. So when I say we should use floating point, that is implicitly
saying that pixman does not support non-FPU hardware. I'm fine with
If someone shows up with (a) a credible claim that he will ship pixman
to a non-trivial number of people in a non-FPU device, and (b) the
resources to maintain an integer version of all of the pixman code,
then that could be considered.
Until then, floating point is fine.
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