2 files changed, 6 insertions, 0 deletions
diff --git a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H
index 6f511c6e4..67265c304 100644
--- a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H
+++ b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.H
@@ -59,6 +59,7 @@ protected:
   CGLineJoin quartz_line_join_;
   CGFloat *quartz_line_pattern;
   int quartz_line_pattern_size;
+  virtual void cache_size(int &width, int &height);
 public:
   Fl_Quartz_Graphics_Driver();
   virtual ~Fl_Quartz_Graphics_Driver() { if (p) free(p); }
diff --git a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.cxx b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.cxx
index 4ea518c9a..f8fab114e 100644
--- a/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.cxx
+++ b/src/drivers/Quartz/Fl_Quartz_Graphics_Driver.cxx
@@ -153,3 +153,8 @@ void Fl_Quartz_Graphics_Driver::XDestroyRegion(Fl_Region r) {
     free(r);
   }
 }
+
+void Fl_Quartz_Graphics_Driver::cache_size(int &width, int &height) {
+  width *= 2 * scale();
+  height *= 2 * scale();
+}