Don't query system option in every DrawBitmap() call under MSW.

Doing this had noticeable (and bad) performance implications so cache the
value of the option during the first call. This doesn't allow changing its
value during the program execution so we may want to provide some way to
update its value later if really needed.

Closes #11172.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61967 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/msw/dc.cpp b/src/msw/dc.cpp
index 46eebf25c5f2f249eee98cf0dedc766091476346..15f83c4955d97322ef583faea5d09bae3de2a40c 100644 (file)
--- a/src/msw/dc.cpp
+++ b/src/msw/dc.cpp
@@ -1214,13 +1214,20 @@ void wxMSWDCImpl::DoDrawBitmap( const wxBitmap &bmp, wxCoord x, wxCoord y, bool
 #ifdef __WIN32__
         // use MaskBlt() with ROP which doesn't do anything to dst in the mask
         // points
+        bool ok = false;
+
+#if wxUSE_SYSTEM_OPTIONS
         // On some systems, MaskBlt succeeds yet is much much slower
         // than the wxWidgets fall-back implementation. So we need
         // to be able to switch this on and off at runtime.
-        bool ok = false;
-#if wxUSE_SYSTEM_OPTIONS
-        if (wxSystemOptions::GetOptionInt(wxT("no-maskblt")) == 0)
-#endif
+        //
+        // NB: don't query the value of the option every time but do it only
+        //     once as otherwise it can have real (and bad) performance
+        //     implications (see #11172)
+        static bool
+            s_maskBltAllowed = wxSystemOptions::GetOptionInt("no-maskblt") == 0;
+        if ( s_maskBltAllowed )
+#endif // wxUSE_SYSTEM_OPTIONS
         {
             HDC cdc = GetHdc();
             HDC hdcMem = ::CreateCompatibleDC(GetHdc());