Avoid crash when trying to access m_window from wxScreenDC.

[wxWidgets.git] / src / msw / dib.cpp

diff --git a/src/msw/dib.cpp b/src/msw/dib.cpp
index f56dae0b1fb92b4feabbe8e29345ec166fcf0222..0c89e7e5add0de12fe4b3f1f5993db65889dabae 100644 (file)
--- a/src/msw/dib.cpp
+++ b/src/msw/dib.cpp
@@ -30,15 +30,16 @@
     #pragma hdrstop
 #endif
 
+#if wxUSE_WXDIB
+
 #ifndef WX_PRECOMP
     #include "wx/string.h"
     #include "wx/log.h"
+    #include "wx/intl.h"
+    #include "wx/bitmap.h"
+    #include "wx/image.h"
 #endif //WX_PRECOMP
 
-#if wxUSE_WXDIB
-
-#include "wx/bitmap.h"
-#include "wx/intl.h"
 #include "wx/file.h"
 
 #include <stdio.h>
@@ -48,7 +49,6 @@
     #include <memory.h>
 #endif
 
-#include "wx/image.h"
 #include "wx/msw/dib.h"
 
 #ifdef __WXWINCE__
@@ -566,7 +566,7 @@ HGLOBAL wxDIB::ConvertFromBitmap(HBITMAP hbmp)
         return NULL;
     }
 
-    if ( !ConvertFromBitmap((BITMAPINFO *)(void *)GlobalPtr(hDIB), hbmp) )
+    if ( !ConvertFromBitmap((BITMAPINFO *)(void *)GlobalPtrLock(hDIB), hbmp) )
     {
         // this really shouldn't happen... it worked the first time, why not
         // now?
@@ -634,7 +634,7 @@ wxPalette *wxDIB::CreatePalette() const
     // and the colour table
     wxCharBuffer rgb(sizeof(RGBQUAD) * biClrUsed);
     RGBQUAD *pRGB = (RGBQUAD*)rgb.data();
-    SelectInHDC(hDC, m_handle);
+    SelectInHDC selectHandle(hDC, m_handle);
     ::GetDIBColorTable(hDC, 0, biClrUsed, pRGB);
     for ( DWORD i = 0; i < biClrUsed; i++, pRGB++ )
     {
@@ -775,14 +775,26 @@ wxImage wxDIB::ConvertToImage() const
             dst[1] = *src++;
             dst[0] = *src++;
 
-            dst += 3;
-
             if ( is32bit )
             {
                 if ( alpha )
-                    *alpha++ = *src;
+                {
+                    // wxImage uses non premultiplied alpha so undo
+                    // premultiplication done in Create() above
+                    const unsigned char a = *src;
+                    *alpha++ = a;
+                    if ( a > 0 )
+                    {
+                        dst[0] = (dst[0] * 255 - 127) / a;
+                        dst[1] = (dst[1] * 255 - 127) / a;
+                        dst[2] = (dst[2] * 255 - 127) / a;
+                    }
+                }
+
                 src++;
             }
+
+            dst += 3;
         }
 
         // pass to the previous line in the image
@@ -800,4 +812,3 @@ wxImage wxDIB::ConvertToImage() const
 #endif // wxUSE_IMAGE
 
 #endif // wxUSE_WXDIB
-