[BUG] CXTPGraphicBitmapPng [UPDATED - 22-o9-2o11]

First:

HBITMAP CXTPGraphicBitmapPng::ConvertToBitmap(BYTE* pbImage, CSize szImage,  int cImgChannels) const
{

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bmi.bmiHeader.biBitCount = 32;   // Here the destination bitmap will be created 32bits even the source png is not 32bits.

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// copy image to screen

    for (yImg = 0; yImg < szImage.cy; yImg++)
    {
        src = pbImage + yImg * wImgRowBytes;
        dst = pBits + yImg * wDIRowBytes;

        for (xImg = 0; xImg < szImage.cx; xImg++)
        {
            r = *src++;
            g = *src++;
            b = *src++;
            *dst++ = b;
            *dst++ = g;
            *dst++ = r;
            a = 0;

            if (cImgChannels == 4)   // Else (cImgChannels != 4), a = 0, so all the destination bitmap alpha bytes will be 0 (the destination bitmap will draw transparent).
            {
                a = *src++;
            }
            *dst++ = a;
        }
    }

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}

And a call to the function

BOOL CXTPGraphicBitmapPng::LoadFromFile(CFile* pFile)
{

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m_bAlpha = (cImgChannels == 4);   // Asumming (cImgChannels != 4). So m_bAlpha = FALSE.

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}

Will cause

AFX_INLINE BOOL CXTPGraphicBitmapPng::IsAlpha() const {
    return m_bAlpha;
}

returning FALSE, and actually
bmi.bmiHeader.biBitCount = 32;   // The destination bitmap is created 32bits.

=======================================================

Second:

HBITMAP AFX_CDECL CXTPImageManagerIcon::LoadBitmapFromFile(LPCTSTR lpszFileName, BOOL* lbAlphaBitmap)
{

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HBITMAP hBmp = (HBITMAP)LoadImage(0, lpszFileName, IMAGE_BITMAP, 0, 0, LR_DEFAULTSIZE | (bAlphaBitmap ? LR_CREATEDIBSECTION : 0) | LR_LOADFROMFILE);   // LoadImage here is always returning 32bits bitmaps even they are 24, 16, 8, 4 or monochrome.

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}

LoadImage is working right outside CXTPImageManagerIcon::LoadBitmapFromFile function

The same problem about LoadImage function for the below functions:

HBITMAP AFX_CDECL CXTPImageManagerIcon::LoadBitmapFromResource(LPCTSTR lpszResource, BOOL* lbAlphaBitmap)

HBITMAP AFX_CDECL CXTPImageManagerIcon::LoadBitmapFromResource(HMODULE hModule, LPCTSTR lpszResource, BOOL* lbAlphaBitmap)

Finally:

This is the correct CXTPGraphicBitmapPng::ConvertToBitmap function that should be

HBITMAP CXTPGraphicBitmapPng::ConvertToBitmap(LPBYTE lpbytImage, CSize szImage, int iImgChannels) const
{
    BITMAPINFO bmi;
   
    // Initialize header to 0s.
    ::ZeroMemory(&bmi, sizeof(BITMAPINFO));
   
    // Fill out the fields you care about.
    bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bmi.bmiHeader.biWidth = szImage.cx;
    bmi.bmiHeader.biHeight = -szImage.cy;
    bmi.bmiHeader.biPlanes = 1;
    bmi.bmiHeader.biBitCount = (WORD)(iImgChannels == 4 ? 32 : 24);
    bmi.bmiHeader.biCompression = BI_RGB;
   
    HBITMAP hBitmap;
    LPBYTE lpbytBits;
   
    hBitmap = ::CreateDIBSection(::CreateCompatibleDC(NULL), &bmi, DIB_RGB_COLORS, (LPVOID*)&lpbytBits, NULL, 0);
   
    if (hBitmap == NULL)
        return NULL;
   
    // Copy image
    LPBYTE lpbytSrc, lpbytDst;
   
    lpbytSrc = lpbytImage;
    lpbytDst = lpbytBits;
   
    for (int i = 0; i < szImage.cy; i ++)
    {
        for (int j = 0; j < szImage.cx; j ++)
        {
            lpbytDst[0] = lpbytSrc[2];
            lpbytDst[1] = lpbytSrc[1];
            lpbytDst[2] = lpbytSrc[0];
           
            if (iImgChannels == 4)
                lpbytDst[3] = lpbytSrc[3];
           
            lpbytSrc += iImgChannels;
            lpbytDst += iImgChannels;
        }
       
        if (iImgChannels == 3)
            lpbytDst += -(szImage.cx * 3) & 3;
    }
   
    return hBitmap;
}

And the LoadImage implementation that should be

(HBITMAP)::LoadImage(NULL, lpszFileName, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE);   // For files.

And

(HBITMAP)::LoadImage(hModule, lpszResource, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION);   // For resources.

Thank you for your understand ;)