[cairo] [Pixman] Floating point API in Pixman

Krzysztof Kosiński tweenk.pl at gmail.com
Mon Aug 16 13:44:42 PDT 2010


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?

How much slower is softfloat - a factor of 5, 15 or 500?

Another thing we have to take into account is that new versions of
Cairo/Pixman are rather unlikely to find their way onto legacy ARM
hardware, because it consists mostly of embedded or mobile systems
where updating the software is either quite a task or not possible. So
the question we should be answering is: what proportion of *new* ARM
systems which Cairo will run on will not have an FPU?

I also note that most of the Cairo API uses double precision floats.

Regards, Krzysztof


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