#define PI 3.14159265358979323846
#define HALFPI 1.57079632679489661923 /* PI divided by 2 */
#define QUARTPI 0.78539816339744830962 /* PI divided by 4 */
#define PI 3.14159265358979323846
#define HALFPI 1.57079632679489661923 /* PI divided by 2 */
#define QUARTPI 0.78539816339744830962 /* PI divided by 4 */
void scale_mtx2(GRFMTX_2D m, const double sx, const double sy);
void rot_mtx2(GRFMTX_2D m, const double theta);
void mult_mtx2(GRFMTX_2D m1, GRFMTX_2D m2, GRFMTX_2D result);
void scale_mtx2(GRFMTX_2D m, const double sx, const double sy);
void rot_mtx2(GRFMTX_2D m, const double theta);
void mult_mtx2(GRFMTX_2D m1, GRFMTX_2D m2, GRFMTX_2D result);
void rotate2d(double x[], double y[], int pts, double angle);
void xlat2d(double x[], double y[], int pts, double xoffset, double yoffset);
void scale2d(double x[], double y[], int pts, double xfact, double yfact);
void rotate2d(double x[], double y[], int pts, double angle);
void xlat2d(double x[], double y[], int pts, double xoffset, double yoffset);
void scale2d(double x[], double y[], int pts, double xfact, double yfact);