Index: nsThebesDeviceContext.cpp
===================================================================
RCS file: /cvsroot/mozilla/gfx/src/thebes/nsThebesDeviceContext.cpp,v
retrieving revision 1.76
diff -d -u -p -r1.76 nsThebesDeviceContext.cpp
--- nsThebesDeviceContext.cpp	16 Apr 2008 03:27:03 -0000	1.76
+++ nsThebesDeviceContext.cpp	17 Apr 2008 17:25:31 -0000
@@ -170,8 +170,9 @@ nsThebesDeviceContext::SetDPI()
         }
 
 #if defined(MOZ_ENABLE_GTK2)
-        float screenWidthIn = float(::gdk_screen_width_mm()) / 25.4f;
-        PRInt32 OSVal = NSToCoordRound(float(::gdk_screen_width()) / screenWidthIn);
+        GdkScreen *screen = gdk_screen_get_default();
+        (void)gtk_settings_get_for_screen(screen); // Make sure init is run so we have a resolution
+        PRInt32 OSVal = (PRInt32) gdk_screen_get_resolution(screen);
 
         if (prefDPI == 0) // Force the use of the OS dpi
             dpi = OSVal;