Fix transparency in toolbar buttons when not using comctl32.dll v6.

Old versions of comctl32.dll don't support alpha in the toolbar image list, so
use the masks only for them.

Closes #2609.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75785 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/imaglist.cpp

@@ -87,7 +87,8 @@ bool wxImageList::Create(int width, int height, bool mask, int initial)
     flags |= ILC_COLOR32;
 #endif
 
-    if ( mask )
+    // For comctl32.dll < 6 always use masks as it doesn't support alpha.
+    if ( mask || wxApp::GetComCtl32Version() < 600 )
         flags |= ILC_MASK;
 
     // Grow by 1, I guess this is reasonable behaviour most of the time
@@ -148,20 +149,37 @@ int wxImageList::Add(const wxBitmap& bitmap, const wxBitmap& mask)
     // course, very inefficient but it's better than wrong appearance so we do
     // this for now until a better way can be found.
     AutoHBITMAP hbmpRelease;
+    bool useMask;
     if ( bitmap.HasAlpha() )
     {
-        hbmp = wxDIB(bitmap.ConvertToImage(),
-                     wxDIB::PixelFormat_NotPreMultiplied).Detach();
+        wxImage img = bitmap.ConvertToImage();
+
+        // For comctl32.dll < 6 remove alpha channel from image
+        // to prevent possible interferences with the mask.
+        if ( wxApp::GetComCtl32Version() < 600 )
+        {
+            img.ClearAlpha();
+            useMask = true;
+        }
+        else
+        {
+            useMask = false;
+        }
+
+        hbmp = wxDIB(img, wxDIB::PixelFormat_NotPreMultiplied).Detach();
         hbmpRelease.Init(hbmp);
     }
     else
 #endif // wxUSE_WXDIB && wxUSE_IMAGE
+    {
         hbmp = GetHbitmapOf(bitmap);
+        useMask = true;
+    }
 
     // Use mask only if we don't have alpha, the bitmap isn't drawn correctly
     // if we use both.
     AutoHBITMAP hbmpMask;
-    if ( !bitmap.HasAlpha() )
+    if ( useMask )
         hbmpMask.Init(GetMaskForImage(bitmap, mask));
 
     int index = ImageList_Add(GetHImageList(), hbmp, hbmpMask);
@@ -185,8 +203,14 @@ int wxImageList::Add(const wxBitmap& bitmap, const wxColour& maskColour)
     AutoHBITMAP hbmpRelease;
     if ( bitmap.HasAlpha() )
     {
-        hbmp = wxDIB(bitmap.ConvertToImage(),
-                     wxDIB::PixelFormat_NotPreMultiplied).Detach();
+        wxImage img = bitmap.ConvertToImage();
+
+        if ( wxApp::GetComCtl32Version() < 600 )
+        {
+            img.ClearAlpha();
+        }
+
+        hbmp = wxDIB(img, wxDIB::PixelFormat_NotPreMultiplied).Detach();
         hbmpRelease.Init(hbmp);
     }
     else
@@ -224,21 +248,38 @@ bool wxImageList::Replace(int index,
                           const wxBitmap& mask)
 {
     HBITMAP hbmp;
+    bool useMask;
 
 #if wxUSE_WXDIB && wxUSE_IMAGE
     // See the comment in Add() above.
     AutoHBITMAP hbmpRelease;
     if ( bitmap.HasAlpha() )
     {
-        hbmp = wxDIB(bitmap.ConvertToImage(),
-                     wxDIB::PixelFormat_NotPreMultiplied).Detach();
+        wxImage img = bitmap.ConvertToImage();
+
+        if ( wxApp::GetComCtl32Version() < 600 )
+        {
+            img.ClearAlpha();
+            useMask = true;
+        }
+        else
+        {
+            useMask = false;
+        }
+
+        hbmp = wxDIB(img, wxDIB::PixelFormat_NotPreMultiplied).Detach();
         hbmpRelease.Init(hbmp);
     }
     else
 #endif // wxUSE_WXDIB && wxUSE_IMAGE
+    {
         hbmp = GetHbitmapOf(bitmap);
+        useMask = true;
+    }
 
-    AutoHBITMAP hbmpMask(GetMaskForImage(bitmap, mask));
+    AutoHBITMAP hbmpMask;
+    if ( useMask )
+        hbmpMask.Init(GetMaskForImage(bitmap, mask));
 
     if ( !ImageList_Replace(GetHImageList(), index, hbmp, hbmpMask) )
     {

src/msw/toolbar.cpp

@@ -663,7 +663,10 @@ void wxToolBar::CreateDisabledImageList()
                                         (
                                             sizeBitmap.x,
                                             sizeBitmap.y,
-                                            bmpDisabled.GetMask() != NULL,
+                                            // Don't use mask if we have alpha
+                                            // (wxImageList will fall back to
+                                            // mask if alpha not supported)
+                                            !bmpDisabled.HasAlpha(),
                                             GetToolsCount()
                                         );
                 break;