+/* clip.c */
+int clipsegment(double *x1, double *y1, double *x2, double *y2, const double u, const double v);
+int clipsector(double *x1, double *y1, double *x2, double *y2, const double u, const double v);
+int clipcircle(double *x1, double *y1, double *x2, double *y2, const double cx, const double cy, const double radius, double t1, double t2);
+int cliptriangle(double *x1, double *y1, double *x2, double *y2, const double u, const double v, const int clip_xaxis);
+/* xform.c */
+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(GRFMTX_2D m1, GRFMTX_2D m2, GRFMTX_2D result);
+void xform_mtx2(GRFMTX_2D const m, double *x, double *y);