INT_PI            268 libavfilter/vf_rotate.c     if (a < 0) a = INT_PI-a; // 0..inf
INT_PI            269 libavfilter/vf_rotate.c     a %= 2 * INT_PI;         // 0..2PI
INT_PI            271 libavfilter/vf_rotate.c     if (a >= INT_PI*3/2) a -= 2*INT_PI;  // -PI/2 .. 3PI/2
INT_PI            272 libavfilter/vf_rotate.c     if (a >= INT_PI/2  ) a = INT_PI - a; // -PI/2 ..  PI/2
INT_PI            485 libavfilter/vf_rotate.c     c = int_sin(angle_int + INT_PI/2);