2x banner images!

Source/Core/DolphinWX/Src/WxUtils.cpp

@@ -9,6 +9,10 @@
 
 #include "WxUtils.h"
 
+#ifdef __APPLE__
+#import <AppKit/AppKit.h>
+#endif
+
 namespace WxUtils {
 
 // Launch a file according to its mime type
@@ -40,6 +44,18 @@ void Explore(const char *path)
 	}
 }
 
+double GetCurrentBitmapLogicalScale()
+{
+#ifdef __APPLE__
+	// wx doesn't expose this itself, unfortunately.
+    if ([[NSScreen mainScreen] respondsToSelector:@selector(backingScaleFactor)])
+	{
+        return [[NSScreen mainScreen] backingScaleFactor];
+	}
+#endif
+	return 1.0;
+}
+
 }  // namespace
 
 std::string WxStrToStr(const wxString& str)