/* clip.cpp */
int clip_rect(double *x1, double *y1, double *x2, double *y2, const double rect[4]);
int clip_segment(double *x1, double *y1, double *x2, double *y2, const double u, const double v);
/* clip.cpp */
int clip_rect(double *x1, double *y1, double *x2, double *y2, const double rect[4]);
int clip_segment(double *x1, double *y1, double *x2, double *y2, const double u, const double v);