void rot_mtx2 (GRFMTX_2D m, const double theta);
void mult_mtx2 (const GRFMTX_2D m1, const GRFMTX_2D m2, GRFMTX_2D result);
void xform_mtx2 (const GRFMTX_2D m, double& x, double& y);
+void copy_mtx2 (GRFMTX_2D to, const GRFMTX_2D from);
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);