tree 5ac5710de5aa1643f4efc44e1b17318cc66f10cb
parent 768590a99d36e87dd00df30435f274a4567f6ce3
author Alexei Podtelezhnikov <apodtele@gmail.com> 1355983402 -0500
committer Alexei Podtelezhnikov <apodtele@gmail.com> 1355983402 -0500

[base] Improve trigonometric core.

FreeType used to rely on a 24-step iteration CORDIC algorithm to
calculate trigonometric functions and rotate vectors. It turns out
that once the vector is in the right half-plane, the initial rotation
by 63 degrees is not necessary. The algorithm is perfectly capable
to converge to any angle starting from the second 45 degree rotation.
This patch removes the first rotation and makes it a 23-step CORDIC
algorithm.

* src/base/fttrigon.c (FT_TRIG_SCALE, FT_TRIG_COSCALE): Update macro
values.
(ft_trig_pseudo_rotate, ft_trig_pseudo_polarize): Remove initial
rotation.