Mac-specific: Fix for retina display

lionsupport.h

@@ -15,6 +15,9 @@ public:
      * Adds fullscreen button to window for Lion.
      */
     static void addFullscreen(MainWindow *window);
+
+    //Check for retina display
+    static bool isRetinaDisplay();
 };
 
 #endif // LIONSUPPORT_H

lionsupport.mm

@@ -1,4 +1,5 @@
 #include <AppKit/NSWindow.h>
+#include <AppKit/NSScreen.h>
 #include "lionsupport.h"
 
 bool LionSupport::isLion()
@@ -21,3 +22,13 @@ void LionSupport::addFullscreen(MainWindow *window)
 #warning No fullscreen support will be included in this build
 #endif
 }
+
+bool LionSupport::isRetinaDisplay()
+{
+#if defined(MAC_OS_X_VERSION_10_7) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
+  return( [ [ NSScreen mainScreen ] respondsToSelector:@selector( backingScaleFactor ) ]
+          && [ [ NSScreen mainScreen ] backingScaleFactor ] > 1.5 );
+#else
+  return false;
+#endif
+}

main.cc

@@ -33,6 +33,10 @@
 
 #include "gddebug.hh"
 
+#ifdef Q_OS_MAC
+#include "lionsupport.h"
+#endif
+
 void gdMessageHandler( QtMsgType type, const char *msg )
 {
   QString message = QString::fromUtf8( msg );
@@ -83,7 +87,12 @@ int main( int argc, char ** argv )
 {
   #ifdef Q_OS_MAC
     setenv("LANG", "en_US.UTF-8", 1);
-    setenv("QT_GRAPHICSSYSTEM", "raster", 1);
+
+   // Check for retina display
+   if( LionSupport::isRetinaDisplay() )
+     QApplication::setGraphicsSystem( "native" );
+   else
+     QApplication::setGraphicsSystem( "raster" );
   #endif
 
   // The following clause fixes a race in the MinGW runtime where throwing