CODEWITHSUNDEEP
c++gdi+
Maximiliano Santa Cruz
Maximiliano Santa Cruz

Reputation: 401

Bitmap::FromFile method returns NULL on x86

I've this piece of code working on Windows 7 64-bit: it allows me to transform a representation of an Image contained into a std::string (Base64EncodedImage) to a GdiPlus::Bitmap:

HRESULT hr; 
using namespace Gdiplus;
std::string decodedImage = Base64EncodedImage;
DWORD imageSize = decodedImage.length();

HGLOBAL hMem = ::GlobalAlloc(GMEM_MOVEABLE, imageSize);
if (!hMem)
    ErrorExit(TEXT("GlobalAlloc")); //http://msdn.microsoft.com/en-us/library/windows/desktop/ms682499(v=vs.85).aspx

LPVOID pImage = ::GlobalLock(hMem);
if (!pImage)
    ErrorExit(TEXT("GlobalLock"));

CopyMemory(pImage, decodedImage.c_str(), imageSize);
IStream* pStream = NULL;

BitmapData* bitmapData = new BitmapData;
if (::CreateStreamOnHGlobal(hMem, FALSE, &pStream) != S_OK)
    ErrorExit(TEXT("CreateStreamOnHGlobal"));
else
{
    bitmap = Bitmap::FromStream(pStream);   //FAILS on WIN32
    if (!bitmap)
        ErrorExit(TEXT("FromStream"));

    RECT clientRect;
    GetClientRect(hwnd, &clientRect);

    bitmapClone = bitmap->Clone(0, 0, clientRect.right, clientRect.bottom, PixelFormatDontCare);
    delete bitmap;
    bitmap = NULL;    
}

But it fails on Windows 7 32-bit, specifically on this line:

bitmap = Bitmap::FromStream(pStream);

It always returns NULL, but I can't get how is this working on x64 but not in x86. If someone can enlighten me, I'll be grateful.

Thanks!

Upvotes: 5

Views: 5030

Answers (1)

Sergey Vyacheslavovich Brunov
Sergey Vyacheslavovich Brunov

Reputation: 18136

The code you've provided works well for me.

But when I've commented the GDI+ initialization, the Bitmap::FromStream(pStream) method always returns NULL pointer.

Do you have the GDI+ initialization?

GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
// Initialize GDI+.
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

By the way, the GDI+ uninitialization:

GdiplusShutdown(gdiplusToken);

Upvotes: 13

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