1 files changed, 11 insertions, 2 deletions
diff --git a/Source/WebCore/platform/mac/PlatformScreenMac.mm b/Source/WebCore/platform/mac/PlatformScreenMac.mm
index 5dbfcf4..916fc9f 100644
--- a/Source/WebCore/platform/mac/PlatformScreenMac.mm
+++ b/Source/WebCore/platform/mac/PlatformScreenMac.mm
@@ -76,12 +76,21 @@ NSScreen *screenForWindow(NSWindow *window)
     return nil;
 }
 
+static CGFloat windowScaleFactor(NSWindow *window)
+{
+#if !defined(BUILDING_ON_LEOPARD) && !defined(BUILDING_ON_SNOW_LEOPARD)
+    return [window backingScaleFactor];
+#else
+    return [window userSpaceScaleFactor];
+#endif
+}
+
 FloatRect toUserSpace(const NSRect& rect, NSWindow *destination)
 {
     FloatRect userRect = rect;
     userRect.setY(NSMaxY([screenForWindow(destination) frame]) - (userRect.y() + userRect.height())); // flip
     if (destination)
-        userRect.scale(1 / [destination userSpaceScaleFactor]); // scale down
+        userRect.scale(1 / windowScaleFactor(destination)); // scale down
     return userRect;
 }
 
@@ -89,7 +98,7 @@ NSRect toDeviceSpace(const FloatRect& rect, NSWindow *source)
 {
     FloatRect deviceRect = rect;
     if (source)
-        deviceRect.scale([source userSpaceScaleFactor]); // scale up
+        deviceRect.scale(windowScaleFactor(source)); // scale up
     deviceRect.setY(NSMaxY([screenForWindow(source) frame]) - (deviceRect.y() + deviceRect.height())); // flip
     return deviceRect;
 }