## CGAL::rational_rotation_approximation

#include <CGAL/rational_rotation.h>

template <RingNumberType>

void

rational_rotation_approximation ( | RingNumberType dirx, RingNumberType diry, RingNumberType & sin_num, RingNumberType & cos_num, RingNumberType & denom, RingNumberType eps_num, RingNumberType eps_den)

|  | computes integers sin_num, cos_num and denom, such that sin_num/denom approximates the sine of direction (dirx,diry). The difference between the sine and the approximating rational is bounded by eps_num/eps_den. Precondition: eps_num 0.

### Implementation

The approximation is based on Farey sequences as described in the rational rotation method presented by Canny and Ressler at the 8th SoCG 1992. We use a slower version which needs no division operation in the approximation.

### See Also

CGAL::Aff_transformation_2<Kernel>