C++ (Cpp) ScopedComPtr::GetFrame示例

static Bitmap *WICDecodeImageFromStream(IStream *stream)
{
    ScopedCom com;

#define HR(hr) if (FAILED(hr)) return NULL;
    ScopedComPtr<IWICImagingFactory> pFactory;
    if (!pFactory.Create(CLSID_WICImagingFactory)) return NULL;
    ScopedComPtr<IWICBitmapDecoder> pDecoder;
    HR(pFactory->CreateDecoderFromStream(stream, NULL, WICDecodeMetadataCacheOnDemand,
                                         &pDecoder));
    ScopedComPtr<IWICBitmapFrameDecode> srcFrame;
    HR(pDecoder->GetFrame(0, &srcFrame));
    ScopedComPtr<IWICFormatConverter> pConverter;
    HR(pFactory->CreateFormatConverter(&pConverter));
    HR(pConverter->Initialize(srcFrame, GUID_WICPixelFormat32bppBGRA,
                              WICBitmapDitherTypeNone, NULL, 0.f, WICBitmapPaletteTypeCustom));

    UINT w, h;
    HR(pConverter->GetSize(&w, &h));
    double xres, yres;
    HR(pConverter->GetResolution(&xres, &yres));
    Bitmap bmp(w, h, PixelFormat32bppARGB);
    Rect bmpRect(0, 0, w, h);
    BitmapData bmpData;
    Status ok = bmp.LockBits(&bmpRect, ImageLockModeWrite, PixelFormat32bppARGB, &bmpData);
    if (ok != Ok)
        return NULL;
    HR(pConverter->CopyPixels(NULL, bmpData.Stride, bmpData.Stride * h, (BYTE *)bmpData.Scan0));
    bmp.UnlockBits(&bmpData);
    bmp.SetResolution((REAL)xres, (REAL)yres);
#undef HR

    // hack to avoid the use of ::new (because there won't be a corresponding ::delete)
    return bmp.Clone(0, 0, w, h, PixelFormat32bppARGB);
}