Give a meaningful default implementation to a few more member functions of class Fl_Graphics_Driver.

FL/Fl_Graphics_Driver.H

@@ -269,27 +269,27 @@ public:
   /** see fl_line(int, int, int, int) */
   virtual void line(int x, int y, int x1, int y1) {}
   /** see fl_line(int, int, int, int, int, int) */
-  virtual void line(int x, int y, int x1, int y1, int x2, int y2) {}
+  virtual void line(int x, int y, int x1, int y1, int x2, int y2);
   /** see fl_xyline(int, int, int) */
-  virtual void xyline(int x, int y, int x1) {}
+  virtual void xyline(int x, int y, int x1);
   /** see fl_xyline(int, int, int, int) */
-  virtual void xyline(int x, int y, int x1, int y2) {}
+  virtual void xyline(int x, int y, int x1, int y2);
   /** see fl_xyline(int, int, int, int, int) */
-  virtual void xyline(int x, int y, int x1, int y2, int x3) {}
+  virtual void xyline(int x, int y, int x1, int y2, int x3);
   /** see fl_yxline(int, int, int) */
-  virtual void yxline(int x, int y, int y1) {}
+  virtual void yxline(int x, int y, int y1);
   /** see fl_yxline(int, int, int, int) */
-  virtual void yxline(int x, int y, int y1, int x2) {}
+  virtual void yxline(int x, int y, int y1, int x2);
   /** see fl_yxline(int, int, int, int, int) */
-  virtual void yxline(int x, int y, int y1, int x2, int y3) {}
+  virtual void yxline(int x, int y, int y1, int x2, int y3);
   /** see fl_loop(int, int, int, int, int, int) */
-  virtual void loop(int x0, int y0, int x1, int y1, int x2, int y2) {}
+  virtual void loop(int x0, int y0, int x1, int y1, int x2, int y2);
   /** see fl_loop(int, int, int, int, int, int, int, int) */
-  virtual void loop(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3) {}
+  virtual void loop(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3);
   /** see fl_polygon(int, int, int, int, int, int) */
   virtual void polygon(int x0, int y0, int x1, int y1, int x2, int y2) {}
   /** see fl_polygon(int, int, int, int, int, int, int, int) */
-  virtual void polygon(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3) {}
+  virtual void polygon(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3);
   // --- clipping
   /** see fl_push_clip() */
   virtual void push_clip(int x, int y, int w, int h) {}

src/Fl_Graphics_Driver.cxx

@@ -332,6 +332,59 @@ Fl_Offscreen Fl_Graphics_Driver::get_offscreen_and_delete_image_surface(Fl_Image
   return off;
 }
 
+void Fl_Graphics_Driver::xyline(int x, int y, int x1) {
+  line(x, y, x1, y);
+}
+
+void Fl_Graphics_Driver::xyline(int x, int y, int x1, int y2) {
+  line(x, y, x1, y);
+  line(x1, y, x1, y2);
+}
+
+void Fl_Graphics_Driver::xyline(int x, int y, int x1, int y2, int x3) {
+  line(x, y, x1, y);
+  line(x1, y, x1, y2);
+  line(x1, y2, x3, y2);
+}
+
+void Fl_Graphics_Driver::yxline(int x, int y, int y1) {
+  line(x, y, x, y1);
+}
+
+void Fl_Graphics_Driver::yxline(int x, int y, int y1, int x2) {
+  line(x, y, x, y1);
+  line(x, y1, x2, y1);
+}
+
+void Fl_Graphics_Driver::yxline(int x, int y, int y1, int x2, int y3) {
+  line(x, y, x, y1);
+  line(x, y1, x2, y1);
+  line(x2, y1, x2, y3);
+}
+
+void Fl_Graphics_Driver::line(int x, int y, int x1, int y1, int x2, int y2) {
+  line(x, y, x1, y1);
+  line(x1, y1, x2, y2);
+}
+
+void Fl_Graphics_Driver::loop(int x0, int y0, int x1, int y1, int x2, int y2) {
+  line(x0, y0, x1, y1);
+  line(x1, y1, x2, y2);
+  line(x2, y2, x0, y0);
+}
+
+void Fl_Graphics_Driver::loop(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3) {
+  line(x0, y0, x1, y1);
+  line(x1, y1, x2, y2);
+  line(x2, y2, x3, y3);
+  line(x3, y3, x0, y0);
+}
+
+void Fl_Graphics_Driver::polygon(int x0, int y0, int x1, int y1, int x2, int y2, int x3, int y3) {
+  polygon(x0, y0, x1, y1, x3, y3);
+  polygon(x1, y1, x2, y2, x3, y3);
+}
+
 /**
  \}
  \endcond