added debug checks

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@20210 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

diff --git a/src/msw/dc.cpp b/src/msw/dc.cpp
index c153967b61f0ad8622bc82238a0529ac9dcdfa54..e44692390d80cecf56123bda38d33e10ace0bd60 100644 (file)
--- a/src/msw/dc.cpp
+++ b/src/msw/dc.cpp
@@ -2303,7 +2303,7 @@ static void
 wxAlphaBlend(wxDC& dc, int xDst, int yDst, int w, int h, const wxBitmap& bmpSrc)
 {
     // get the destination DC pixels
-    wxBitmap bmpDst(w, h, 32);
+    wxBitmap bmpDst(w, h, 32 /* force creating RGBA DIB */);
     MemoryHDC hdcMem;
     SelectInHDC select(hdcMem, GetHbitmapOf(bmpDst));
 
@@ -2316,6 +2316,9 @@ wxAlphaBlend(wxDC& dc, int xDst, int yDst, int w, int h, const wxBitmap& bmpSrc)
     wxRawBitmapData dataDst(bmpDst),
                     dataSrc(bmpSrc);
 
+    wxCHECK_RET( dataDst && dataSrc,
+                    _T("failed to get raw data in wxAlphaBlend") );
+
     wxRawBitmapIterator pDst(dataDst),
                         pSrc(dataSrc);