don't always create DIBs in wxBitmap(wxImage) ctor

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@55153 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -135,7 +135,9 @@ wxMSW:
 - Fix quoting of arguments passed to wxExecute(char **) (Brian Ravnsgaard Riis).
 - Support disabling items before adding them to the menu (Christian Walther).
 - Allow to call SetFont(wxNullFont) to reset the font to default.
-- Implement UUID::operator==() and !=() (SQLAware).
+- Implement UUID::operator==() and !=() (SQLAware Corporation).
+- Fixed long standing (introduced in 2.6.3) bug which resulted in always
+  creating a DIB and not DDB in wxBitmap(const wxImage&) ctor.
 
 wxGTK:
 

src/msw/bitmap.cpp

@@ -808,14 +808,15 @@ bool wxBitmap::CreateFromImage(const wxImage& image, int depth, WXHDC hdc)
     if ( !dib.IsOk() )
         return false;
 
-    if ( depth == -1 )
-        depth = dib.GetDepth(); // Get depth from image if none specified
+    const bool hasAlpha = image.HasAlpha();
 
     // store the bitmap parameters
-    wxBitmapRefData *refData = new wxBitmapRefData;
+    wxBitmapRefData * const refData = new wxBitmapRefData;
     refData->m_width = w;
     refData->m_height = h;
-    refData->m_hasAlpha = image.HasAlpha();
+    refData->m_hasAlpha = hasAlpha;
+    refData->m_depth = depth == -1 ? (hasAlpha ? 32 : 24)
+                                   : depth;
 
     m_refData = refData;
 
@@ -826,20 +827,17 @@ bool wxBitmap::CreateFromImage(const wxImage& image, int depth, WXHDC hdc)
     // are we going to use DIB?
     //
     // NB: DDBs don't support alpha so if we have alpha channel we must use DIB
-    if ( image.HasAlpha() || wxShouldCreateDIB(w, h, depth, hdc) )
+    if ( hasAlpha || wxShouldCreateDIB(w, h, depth, hdc) )
     {
         // don't delete the DIB section in dib object dtor
         hbitmap = dib.Detach();
 
         refData->m_isDIB = true;
-        refData->m_depth = depth;
     }
 #ifndef ALWAYS_USE_DIB
     else // we need to convert DIB to DDB
     {
         hbitmap = dib.CreateDDB((HDC)hdc);
-
-        refData->m_depth = depth;
     }
 #endif // !ALWAYS_USE_DIB