+namespace
+{
+
+// helper of DoInsertOrAppend(): returns the HBITMAP to use in MENUITEMINFO
+HBITMAP GetHBitmapForMenu(wxMenuItem *pItem, bool checked = true)
+{
+ // Under versions of Windows older than Vista we can't pass HBITMAP
+ // directly as hbmpItem for 2 reasons:
+ // 1. We can't draw it with transparency then (this is not
+ // very important now but would be with themed menu bg)
+ // 2. Worse, Windows inverts the bitmap for the selected
+ // item and this looks downright ugly
+ //
+ // So we prefer to instead draw it ourselves in MSWOnDrawItem().by using
+ // HBMMENU_CALLBACK when inserting it
+ //
+ // However under Vista using HBMMENU_CALLBACK causes the entire menu to be
+ // drawn using the classic theme instead of the current one and it does
+ // handle transparency just fine so do use the real bitmap there
+#if wxUSE_IMAGE
+ if ( wxGetWinVersion() >= wxWinVersion_Vista )
+ {
+ wxBitmap bmp = pItem->GetBitmap(checked);
+ if ( bmp.IsOk() )
+ {
+ // we must use PARGB DIB for the menu bitmaps so ensure that we do
+ wxImage img(bmp.ConvertToImage());
+ if ( !img.HasAlpha() )
+ {
+ img.InitAlpha();
+ pItem->SetBitmap(img, checked);
+ }
+
+ return GetHbitmapOf(pItem->GetBitmap(checked));
+ }
+ }
+#endif // wxUSE_IMAGE
+
+ return HBMMENU_CALLBACK;
+}
+
+} // anonymous namespace
+