Fix duplicate wxContextMenuEvent generation in wxMSW.

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

diff --git a/src/msw/dib.cpp b/src/msw/dib.cpp
index 8da2f37757c6f6934244972b3d857f63b8e7d902..b12baf0f83fe751c48a6f6b05b854663a9b81ef8 100644 (file)
--- a/src/msw/dib.cpp
+++ b/src/msw/dib.cpp
@@ -6,7 +6,7 @@
 // Created:     03.03.03 (replaces the old file with the same name)
 // RCS-ID:      $Id$
 // Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
 // Created:     03.03.03 (replaces the old file with the same name)
 // RCS-ID:      $Id$
 // Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>

-// License:     wxWindows licence
+// Licence:     wxWindows licence

 ///////////////////////////////////////////////////////////////////////////////
 
 /*
 ///////////////////////////////////////////////////////////////////////////////
 
 /*


@@ -30,29 +30,23 @@
     #pragma hdrstop
 #endif
 
     #pragma hdrstop
 #endif
 

+#if wxUSE_WXDIB
+

 #ifndef WX_PRECOMP
     #include "wx/string.h"
     #include "wx/log.h"
 #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
 
 #endif //WX_PRECOMP
 

-#if wxUSE_WXDIB
-
-#include "wx/bitmap.h"
-#include "wx/intl.h"

 #include "wx/file.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "wx/file.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 

-#if !defined(__MWERKS__) && !defined(__SALFORDC__)
-    #include <memory.h>
-#endif
-
-#ifdef __GNUWIN32_OLD__
-    #include "wx/msw/gnuwin32/extra.h"
-#endif
+#include <memory.h>

 
 

-#include "wx/image.h"

 #include "wx/msw/dib.h"
 
 #ifdef __WXWINCE__
 #include "wx/msw/dib.h"
 
 #ifdef __WXWINCE__


@@ -69,7 +63,7 @@ static inline WORD GetNumberOfColours(WORD bitsPerPixel)
 {
     // only 1, 4 and 8bpp bitmaps use palettes (well, they could be used with
     // 24bpp ones too but we don't support this as I think it's quite uncommon)
 {
     // only 1, 4 and 8bpp bitmaps use palettes (well, they could be used with
     // 24bpp ones too but we don't support this as I think it's quite uncommon)

-    return bitsPerPixel <= 8 ? 1 << bitsPerPixel : 0;
+    return (WORD)(bitsPerPixel <= 8 ? 1 << bitsPerPixel : 0);

 }
 
 // wrapper around ::GetObject() for DIB sections
 }
 
 // wrapper around ::GetObject() for DIB sections


@@ -95,44 +89,38 @@ bool wxDIB::Create(int width, int height, int depth)
 {
     // we don't support formats using palettes right now so we only create
     // either 24bpp (RGB) or 32bpp (RGBA) bitmaps
 {
     // we don't support formats using palettes right now so we only create
     // either 24bpp (RGB) or 32bpp (RGBA) bitmaps

-    wxASSERT_MSG( depth, _T("invalid image depth in wxDIB::Create()") );
+    wxASSERT_MSG( depth, wxT("invalid image depth in wxDIB::Create()") );

     if ( depth < 24 )
         depth = 24;
 
     // allocate memory for bitmap structures
     if ( depth < 24 )
         depth = 24;
 
     // allocate memory for bitmap structures

-    static const int sizeHeader = sizeof(BITMAPINFOHEADER);
+    BITMAPINFO info;
+    wxZeroMemory(info);

 
 

-    BITMAPINFO *info = (BITMAPINFO *)malloc(sizeHeader);
-    wxCHECK_MSG( info, false, _T("malloc(BITMAPINFO) failed") );
-
-    memset(info, 0, sizeHeader);
-
-    info->bmiHeader.biSize = sizeHeader;
-    info->bmiHeader.biWidth = width;
+    info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
+    info.bmiHeader.biWidth = width;

 
     // we use positive height here which corresponds to a DIB with normal, i.e.
     // bottom to top, order -- normally using negative height (which means
     // reversed for MS and hence natural for all the normal people top to
     // bottom line scan order) could be used to avoid the need for the image
     // reversal in Create(image) but this doesn't work under NT, only Win9x!
 
     // we use positive height here which corresponds to a DIB with normal, i.e.
     // bottom to top, order -- normally using negative height (which means
     // reversed for MS and hence natural for all the normal people top to
     // bottom line scan order) could be used to avoid the need for the image
     // reversal in Create(image) but this doesn't work under NT, only Win9x!

-    info->bmiHeader.biHeight = height;
+    info.bmiHeader.biHeight = height;

 
 

-    info->bmiHeader.biPlanes = 1;
-    info->bmiHeader.biBitCount = depth;
-    info->bmiHeader.biSizeImage = GetLineSize(width, depth)*height;
+    info.bmiHeader.biPlanes = 1;
+    info.bmiHeader.biBitCount = (WORD)depth;
+    info.bmiHeader.biSizeImage = GetLineSize(width, depth)*height;

 
     m_handle = ::CreateDIBSection
                  (
                     0,              // hdc (unused with DIB_RGB_COLORS)
 
     m_handle = ::CreateDIBSection
                  (
                     0,              // hdc (unused with DIB_RGB_COLORS)

-                    info,           // bitmap description
+                    &info,          // bitmap description

                     DIB_RGB_COLORS, // use RGB, not palette
                     &m_data,        // [out] DIB bits
                     NULL,           // don't use file mapping
                     0               // file mapping offset (not used here)
                  );
 
                     DIB_RGB_COLORS, // use RGB, not palette
                     &m_data,        // [out] DIB bits
                     NULL,           // don't use file mapping
                     0               // file mapping offset (not used here)
                  );
 

-    free(info);
-

     if ( !m_handle )
     {
         wxLogLastError(wxT("CreateDIBSection"));
     if ( !m_handle )
     {
         wxLogLastError(wxT("CreateDIBSection"));


@@ -147,14 +135,12 @@ bool wxDIB::Create(int width, int height, int depth)
     return true;
 }
 
     return true;
 }
 

-bool wxDIB::Create(const wxBitmap& bmp)
+bool wxDIB::Create(HBITMAP hbmp)

 {
 {

-    wxCHECK_MSG( bmp.Ok(), false, _T("wxDIB::Create(): invalid bitmap") );
+    wxCHECK_MSG( hbmp, false, wxT("wxDIB::Create(): invalid bitmap") );

 
     // this bitmap could already be a DIB section in which case we don't need
     // to convert it to DIB
 
     // this bitmap could already be a DIB section in which case we don't need
     // to convert it to DIB

-    HBITMAP hbmp = GetHbitmapOf(bmp);
-

     DIBSECTION ds;
     if ( GetDIBSection(hbmp, &ds) )
     {
     DIBSECTION ds;
     if ( GetDIBSection(hbmp, &ds) )
     {


@@ -172,13 +158,20 @@ bool wxDIB::Create(const wxBitmap& bmp)
     }
     else // no, it's a DDB -- convert it to DIB
     {
     }
     else // no, it's a DDB -- convert it to DIB
     {

-        const int w = bmp.GetWidth();
-        const int h = bmp.GetHeight();
-        int d = bmp.GetDepth();
+        // prepare all the info we need
+        BITMAP bm;
+        if ( !::GetObject(hbmp, sizeof(bm), &bm) )
+        {
+            wxLogLastError(wxT("GetObject(bitmap)"));
+
+            return false;
+        }
+
+        int d = bm.bmBitsPixel;

         if ( d <= 0 )
             d = wxDisplayDepth();
 
         if ( d <= 0 )
             d = wxDisplayDepth();
 

-        if ( !Create(w, h, d) || !CopyFromDDB(hbmp) )
+        if ( !Create(bm.bmWidth, bm.bmHeight, d) || !CopyFromDDB(hbmp) )

             return false;
     }
 
             return false;
     }
 


@@ -221,7 +214,7 @@ bool wxDIB::CopyFromDDB(HBITMAP hbmp)
                     SRCCOPY
                   ) )
     {
                     SRCCOPY
                   ) )
     {

-        wxLogLastError(_T("BitBlt(DDB -> DIB)"));
+        wxLogLastError(wxT("BitBlt(DDB -> DIB)"));

 
         return false;
     }
 
         return false;
     }


@@ -237,7 +230,7 @@ bool wxDIB::CopyFromDDB(HBITMAP hbmp)
     if ( !GetDIBSection(m_handle, &ds) )
     {
         // we're sure that our handle is a DIB section, so this should work
     if ( !GetDIBSection(m_handle, &ds) )
     {
         // we're sure that our handle is a DIB section, so this should work

-        wxFAIL_MSG( _T("GetObject(DIBSECTION) unexpectedly failed") );
+        wxFAIL_MSG( wxT("GetObject(DIBSECTION) unexpectedly failed") );

 
         return false;
     }
 
         return false;
     }


@@ -275,7 +268,7 @@ bool wxDIB::Load(const wxString& filename)
     m_handle = (HBITMAP)::LoadImage
                          (
                             wxGetInstance(),
     m_handle = (HBITMAP)::LoadImage
                          (
                             wxGetInstance(),

-                            filename,
+                            filename.t_str(),

                             IMAGE_BITMAP,
                             0, 0, // don't specify the size
                             LR_CREATEDIBSECTION | LR_LOADFROMFILE
                             IMAGE_BITMAP,
                             0, 0, // don't specify the size
                             LR_CREATEDIBSECTION | LR_LOADFROMFILE


@@ -284,7 +277,7 @@ bool wxDIB::Load(const wxString& filename)
 
     if ( !m_handle )
     {
 
     if ( !m_handle )
     {

-        wxLogLastError(_T("Loading DIB from file"));
+        wxLogLastError(wxT("Loading DIB from file"));

 
         return false;
     }
 
         return false;
     }


@@ -294,8 +287,9 @@ bool wxDIB::Load(const wxString& filename)
 
 bool wxDIB::Save(const wxString& filename)
 {
 
 bool wxDIB::Save(const wxString& filename)
 {

-    wxCHECK_MSG( m_handle, false, _T("wxDIB::Save(): invalid object") );
+    wxCHECK_MSG( m_handle, false, wxT("wxDIB::Save(): invalid object") );

 
 

+#if wxUSE_FILE

     wxFile file(filename, wxFile::write);
     bool ok = file.IsOpened();
     if ( ok )
     wxFile file(filename, wxFile::write);
     bool ok = file.IsOpened();
     if ( ok )


@@ -303,7 +297,7 @@ bool wxDIB::Save(const wxString& filename)
         DIBSECTION ds;
         if ( !GetDIBSection(m_handle, &ds) )
         {
         DIBSECTION ds;
         if ( !GetDIBSection(m_handle, &ds) )
         {

-            wxLogLastError(_T("GetObject(hDIB)"));
+            wxLogLastError(wxT("GetObject(hDIB)"));

         }
         else
         {
         }
         else
         {


@@ -324,6 +318,9 @@ bool wxDIB::Save(const wxString& filename)
                         file.Write(ds.dsBm.bmBits, sizeImage) == sizeImage;
         }
     }
                         file.Write(ds.dsBm.bmBits, sizeImage) == sizeImage;
         }
     }

+#else // !wxUSE_FILE
+    bool ok = false;
+#endif // wxUSE_FILE/!wxUSE_FILE

 
     if ( !ok )
     {
 
     if ( !ok )
     {


@@ -352,7 +349,7 @@ void wxDIB::DoGetObject() const
         DIBSECTION ds;
         if ( !GetDIBSection(m_handle, &ds) )
         {
         DIBSECTION ds;
         if ( !GetDIBSection(m_handle, &ds) )
         {

-            wxLogLastError(_T("GetObject(hDIB)"));
+            wxLogLastError(wxT("GetObject(hDIB)"));

             return;
         }
 
             return;
         }
 


@@ -373,23 +370,47 @@ void wxDIB::DoGetObject() const
 
 HBITMAP wxDIB::CreateDDB(HDC hdc) const
 {
 
 HBITMAP wxDIB::CreateDDB(HDC hdc) const
 {

-    wxCHECK_MSG( m_handle, 0, _T("wxDIB::CreateDDB(): invalid object") );
+    wxCHECK_MSG( m_handle, 0, wxT("wxDIB::CreateDDB(): invalid object") );

 
     DIBSECTION ds;
     if ( !GetDIBSection(m_handle, &ds) )
     {
 
     DIBSECTION ds;
     if ( !GetDIBSection(m_handle, &ds) )
     {

-        wxLogLastError(_T("GetObject(hDIB)"));
+        wxLogLastError(wxT("GetObject(hDIB)"));

 
         return 0;
     }
 
 
         return 0;
     }
 

-    return ConvertToBitmap((BITMAPINFO *)&ds.dsBmih, hdc, ds.dsBm.bmBits);
+    // how many colours are we going to have in the palette?
+    DWORD biClrUsed = ds.dsBmih.biClrUsed;
+    if ( !biClrUsed )
+    {
+        // biClrUsed field might not be set
+        biClrUsed = GetNumberOfColours(ds.dsBmih.biBitCount);
+    }
+
+    if ( !biClrUsed )
+    {
+        return ConvertToBitmap((BITMAPINFO *)&ds.dsBmih, hdc, ds.dsBm.bmBits);
+    }
+    else
+    {
+        // fake a BITMAPINFO w/o bits, just the palette info
+        wxCharBuffer bmi(sizeof(BITMAPINFO) + (biClrUsed - 1)*sizeof(RGBQUAD));
+        BITMAPINFO *pBmi = (BITMAPINFO *)bmi.data();
+        MemoryHDC hDC;
+        // get the colour table
+        SelectInHDC sDC(hDC, m_handle);
+        ::GetDIBColorTable(hDC, 0, biClrUsed, pBmi->bmiColors);
+        memcpy(&pBmi->bmiHeader, &ds.dsBmih, ds.dsBmih.biSize);
+
+        return ConvertToBitmap(pBmi, hdc, ds.dsBm.bmBits);
+    }

 }
 
 /* static */
 HBITMAP wxDIB::ConvertToBitmap(const BITMAPINFO *pbmi, HDC hdc, void *bits)
 {
 }
 
 /* static */
 HBITMAP wxDIB::ConvertToBitmap(const BITMAPINFO *pbmi, HDC hdc, void *bits)
 {

-    wxCHECK_MSG( pbmi, 0, _T("invalid DIB in ConvertToBitmap") );
+    wxCHECK_MSG( pbmi, 0, wxT("invalid DIB in ConvertToBitmap") );

 
     // here we get BITMAPINFO struct followed by the actual bitmap bits and
     // BITMAPINFO starts with BITMAPINFOHEADER followed by colour info
 
     // here we get BITMAPINFO struct followed by the actual bitmap bits and
     // BITMAPINFO starts with BITMAPINFOHEADER followed by colour info


@@ -525,17 +546,17 @@ HGLOBAL wxDIB::ConvertFromBitmap(HBITMAP hbmp)
     {
         // this is an error which does risk to happen especially under Win9x
         // and which the user may understand so let him know about it
     {
         // this is an error which does risk to happen especially under Win9x
         // and which the user may understand so let him know about it

-        wxLogError(_("Failed to allocated %luKb of memory for bitmap data."),
+        wxLogError(_("Failed to allocate %luKb of memory for bitmap data."),

                    (unsigned long)(size / 1024));
 
         return NULL;
     }
 
                    (unsigned long)(size / 1024));
 
         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?
     {
         // this really shouldn't happen... it worked the first time, why not
         // now?

-        wxFAIL_MSG( _T("wxDIB::ConvertFromBitmap() unexpectedly failed") );
+        wxFAIL_MSG( wxT("wxDIB::ConvertFromBitmap() unexpectedly failed") );

 
         return NULL;
     }
 
         return NULL;
     }


@@ -553,12 +574,16 @@ HGLOBAL wxDIB::ConvertFromBitmap(HBITMAP hbmp)
 
 wxPalette *wxDIB::CreatePalette() const
 {
 
 wxPalette *wxDIB::CreatePalette() const
 {

-    wxCHECK_MSG( m_handle, NULL, _T("wxDIB::CreatePalette(): invalid object") );
+    // GetDIBColorTable not available in eVC3
+#if !defined(__WXMSW__) || defined(_WIN32_WCE) && _WIN32_WCE < 400
+    return NULL;
+#else
+    wxCHECK_MSG( m_handle, NULL, wxT("wxDIB::CreatePalette(): invalid object") );

 
     DIBSECTION ds;
     if ( !GetDIBSection(m_handle, &ds) )
     {
 
     DIBSECTION ds;
     if ( !GetDIBSection(m_handle, &ds) )
     {

-        wxLogLastError(_T("GetObject(hDIB)"));
+        wxLogLastError(wxT("GetObject(hDIB)"));

 
         return 0;
     }
 
         return 0;
     }


@@ -580,18 +605,23 @@ wxPalette *wxDIB::CreatePalette() const
         return NULL;
     }
 
         return NULL;
     }
 

+    MemoryHDC hDC;
+

     // LOGPALETTE struct has only 1 element in palPalEntry array, we're
     // going to have biClrUsed of them so add necessary space
     LOGPALETTE *pPalette = (LOGPALETTE *)
         malloc(sizeof(LOGPALETTE) + (biClrUsed - 1)*sizeof(PALETTEENTRY));
     // LOGPALETTE struct has only 1 element in palPalEntry array, we're
     // going to have biClrUsed of them so add necessary space
     LOGPALETTE *pPalette = (LOGPALETTE *)
         malloc(sizeof(LOGPALETTE) + (biClrUsed - 1)*sizeof(PALETTEENTRY));

-    wxCHECK_MSG( pPalette, NULL, _T("out of memory") );
+    wxCHECK_MSG( pPalette, NULL, wxT("out of memory") );

 
     // initialize the palette header
     pPalette->palVersion = 0x300;  // magic number, not in docs but works
 
     // initialize the palette header
     pPalette->palVersion = 0x300;  // magic number, not in docs but works

-    pPalette->palNumEntries = biClrUsed;
+    pPalette->palNumEntries = (WORD)biClrUsed;

 
 

-    // and the colour table (it starts right after the end of the header)
-    const RGBQUAD *pRGB = (RGBQUAD *)((char *)&ds.dsBmih + ds.dsBmih.biSize);
+    // and the colour table
+    wxCharBuffer rgb(sizeof(RGBQUAD) * biClrUsed);
+    RGBQUAD *pRGB = (RGBQUAD*)rgb.data();
+    SelectInHDC selectHandle(hDC, m_handle);
+    ::GetDIBColorTable(hDC, 0, biClrUsed, pRGB);

     for ( DWORD i = 0; i < biClrUsed; i++, pRGB++ )
     {
         pPalette->palPalEntry[i].peRed = pRGB->rgbRed;
     for ( DWORD i = 0; i < biClrUsed; i++, pRGB++ )
     {
         pPalette->palPalEntry[i].peRed = pRGB->rgbRed;


@@ -606,7 +636,7 @@ wxPalette *wxDIB::CreatePalette() const
 
     if ( !hPalette )
     {
 
     if ( !hPalette )
     {

-        wxLogLastError(_T("CreatePalette"));
+        wxLogLastError(wxT("CreatePalette"));

 
         return NULL;
     }
 
         return NULL;
     }


@@ -615,6 +645,7 @@ wxPalette *wxDIB::CreatePalette() const
     palette->SetHPALETTE((WXHPALETTE)hPalette);
 
     return palette;
     palette->SetHPALETTE((WXHPALETTE)hPalette);
 
     return palette;

+#endif

 }
 
 #endif // wxUSE_PALETTE
 }
 
 #endif // wxUSE_PALETTE


@@ -625,9 +656,9 @@ wxPalette *wxDIB::CreatePalette() const
 
 #if wxUSE_IMAGE
 
 
 #if wxUSE_IMAGE
 

-bool wxDIB::Create(const wxImage& image)
+bool wxDIB::Create(const wxImage& image, PixelFormat pf)

 {
 {

-    wxCHECK_MSG( image.Ok(), false, _T("invalid wxImage in wxDIB ctor") );
+    wxCHECK_MSG( image.IsOk(), false, wxT("invalid wxImage in wxDIB ctor") );

 
     const int h = image.GetHeight();
     const int w = image.GetWidth();
 
     const int h = image.GetHeight();
     const int w = image.GetWidth();


@@ -645,23 +676,58 @@ bool wxDIB::Create(const wxImage& image)
     const int srcBytesPerLine = w * 3;
     const int dstBytesPerLine = GetLineSize(w, bpp);
     const unsigned char *src = image.GetData() + ((h - 1) * srcBytesPerLine);
     const int srcBytesPerLine = w * 3;
     const int dstBytesPerLine = GetLineSize(w, bpp);
     const unsigned char *src = image.GetData() + ((h - 1) * srcBytesPerLine);

-    const unsigned char *alpha = hasAlpha ? image.GetAlpha() + (h - 1)*w : NULL;
+    const unsigned char *alpha = hasAlpha ? image.GetAlpha() + (h - 1)*w
+                                          : NULL;

     unsigned char *dstLineStart = (unsigned char *)m_data;
     for ( int y = 0; y < h; y++ )
     {
     unsigned char *dstLineStart = (unsigned char *)m_data;
     for ( int y = 0; y < h; y++ )
     {

-        // copy one DIB line
+        // Copy one DIB line. Note that RGB components order is reversed in
+        // Windows bitmaps compared to wxImage and is actually BGR.

         unsigned char *dst = dstLineStart;
         unsigned char *dst = dstLineStart;

-        for ( int x = 0; x < w; x++ )
+        if ( alpha )

         {
         {

-            // also, the order of RGB is inversed for DIBs
-            *dst++ = src[2];
-            *dst++ = src[1];
-            *dst++ = src[0];
-
-            src += 3;
+            int x;
+
+            switch ( pf )
+            {
+                case PixelFormat_PreMultiplied:
+                    // Pre-multiply pixel values so that the DIB could be used
+                    // with ::AlphaBlend().
+                    for ( x = 0; x < w; x++ )
+                    {
+                        const unsigned char a = *alpha++;
+                        *dst++ = (unsigned char)((src[2] * a + 127) / 255);
+                        *dst++ = (unsigned char)((src[1] * a + 127) / 255);
+                        *dst++ = (unsigned char)((src[0] * a + 127) / 255);
+                        *dst++ = a;
+                        src += 3;
+                    }
+                    break;
+
+                case PixelFormat_NotPreMultiplied:
+                    // Just copy pixel data without changing it.
+                    for ( x = 0; x < w; x++ )
+                    {
+                        *dst++ = src[2];
+                        *dst++ = src[1];
+                        *dst++ = src[0];
+
+                        *dst++ = *alpha++;
+                        src += 3;
+                    }
+                    break;
+            }

 
 

-            if ( alpha )
-                *dst++ = *alpha++;
+        }
+        else // no alpha channel
+        {
+            for ( int x = 0; x < w; x++ )
+            {
+                *dst++ = src[2];
+                *dst++ = src[1];
+                *dst++ = src[0];
+                src += 3;
+            }

         }
 
         // pass to the previous line in the image
         }
 
         // pass to the previous line in the image


@@ -685,15 +751,26 @@ wxImage wxDIB::ConvertToImage() const
     const int w = GetWidth();
     const int h = GetHeight();
     wxImage image(w, h, false /* don't bother clearing memory */);
     const int w = GetWidth();
     const int h = GetHeight();
     wxImage image(w, h, false /* don't bother clearing memory */);

-    if ( !image.Ok() )
+    if ( !image.IsOk() )

     {
         wxFAIL_MSG( wxT("could not allocate data for image") );
         return wxNullImage;
     }
 
     const int bpp = GetDepth();
     {
         wxFAIL_MSG( wxT("could not allocate data for image") );
         return wxNullImage;
     }
 
     const int bpp = GetDepth();

+
+    // Remember if we have any "real" transparency, i.e. either any partially
+    // transparent pixels or not all pixels are fully opaque or fully
+    // transparent.
+    bool hasAlpha = false;
+    bool hasOpaque = false;
+    bool hasTransparent = false;
+

     if ( bpp == 32 )
     {
     if ( bpp == 32 )
     {

+        // 32 bit bitmaps may be either 0RGB or ARGB and we don't know in
+        // advance which one do we have so suppose we have alpha of them and
+        // get rid of it later if it turns out we didn't.

         image.SetAlpha();
     }
 
         image.SetAlpha();
     }
 


@@ -715,10 +792,42 @@ wxImage wxDIB::ConvertToImage() const
             dst[1] = *src++;
             dst[0] = *src++;
 
             dst[1] = *src++;
             dst[0] = *src++;
 

-            dst += 3;
+            if ( bpp == 32 )
+            {
+                // wxImage uses non premultiplied alpha so undo
+                // premultiplication done in Create() above
+                const unsigned char a = *src;
+                *alpha++ = a;
+
+                // Check what kind of alpha do we have.
+                switch ( a )
+                {
+                    case 0:
+                        hasTransparent = true;
+                        break;
+
+                    default:
+                        // Anything in between means we have real transparency
+                        // and must use alpha channel.
+                        hasAlpha = true;
+                        break;
+
+                    case 255:
+                        hasOpaque = true;
+                        break;
+                }
+
+                if ( a > 0 )
+                {
+                    dst[0] = (dst[0] * 255) / a;
+                    dst[1] = (dst[1] * 255) / a;
+                    dst[2] = (dst[2] * 255) / a;
+                }
+
+                src++;
+            }

 
 

-            if ( alpha )
-                *alpha++ = *src++;
+            dst += 3;

         }
 
         // pass to the previous line in the image
         }
 
         // pass to the previous line in the image


@@ -730,10 +839,15 @@ wxImage wxDIB::ConvertToImage() const
         srcLineStart += srcBytesPerLine;
     }
 
         srcLineStart += srcBytesPerLine;
     }
 

+    if ( hasOpaque && hasTransparent )
+        hasAlpha = true;
+
+    if ( !hasAlpha && image.HasAlpha() )
+        image.ClearAlpha();
+

     return image;
 }
 
 #endif // wxUSE_IMAGE
 
 #endif // wxUSE_WXDIB
     return image;
 }
 
 #endif // wxUSE_IMAGE
 
 #endif // wxUSE_WXDIB

-