void indent_mtx2 (GRFMTX_2D m);
void xlat_mtx2 (GRFMTX_2D m, const double x, const double y);
void scale_mtx2 (GRFMTX_2D m, const double sx, const double sy);
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 indent_mtx2 (GRFMTX_2D m);
void xlat_mtx2 (GRFMTX_2D m, const double x, const double y);
void scale_mtx2 (GRFMTX_2D m, const double sx, const double sy);
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);