c++ - OpenCV 2.4:在 MFC 中显示 cv::Mat

Question

我正在将现有代码库从 IplImage* 更新为较新的 cv::Mat。我想知道如何向 MFC 显示我的 cv::Mat 对象。我们当前使用的解决方案基于旧的 CvvImage 类:

void DrawPicToHDC(IplImage *img, UINT ID, bool bOnPaint)
{
    CDC *pDC = GetDlgItem(ID)->GetDC();
    HDC hDC= pDC->GetSafeHdc();
    CRect rect;
    GetDlgItem(ID)->GetClientRect(&rect);
    CvvImage cimg;
    cimg.CopyOf( img );
    cimg.DrawToHDC( hDC, &rect );
    ReleaseDC( pDC );
}

我遇到了this线程，但不幸的是提供的答案不能满足我的需求，因为答案仍然要求您在显示之前将 Mat 转换为 IplImage*。

有没有办法只使用 cv::Mat 来做到这一点？非常感谢任何帮助。

更新: 在 Kornel 答案的帮助下，我将上述函数调整为使用 cv::Mat 。我现在不需要包含 CvvImage 类:

void DrawPicToHDC(cv::Mat cvImg, UINT ID, bool bOnPaint)
{
    // Get the HDC handle information from the ID passed
    CDC *pDC = GetDlgItem(ID)->GetDC();
    HDC hDCDst = pDC->GetSafeHdc();
    CRect rect;
    GetDlgItem(ID)->GetClientRect(&rect);
    cv::Size winSize(rect.right, rect.bottom);

    // Resize the source to the size of the destination image if necessary
    cv::Mat cvImgTmp(winSize, CV_8UC3);
    if (cvImg.size() != winSize)
    {
        cv::resize(cvImg, cvImgTmp, winSize);
    }
    else
    {
        cvImgTmp = cvImg;
    }

    // Rotate the image
    cv::flip(cvImgTmp,cvImgTmp,0);

    // Initialize the BITMAPINFO structure
    BITMAPINFO bitInfo;
    bitInfo.bmiHeader.biBitCount = 24;
    bitInfo.bmiHeader.biWidth = winSize.width;
    bitInfo.bmiHeader.biHeight = winSize.height;
    bitInfo.bmiHeader.biPlanes = 1;
    bitInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bitInfo.bmiHeader.biCompression = BI_RGB;
    bitInfo.bmiHeader.biClrImportant = 0;
    bitInfo.bmiHeader.biClrUsed = 0;
    bitInfo.bmiHeader.biSizeImage = 0;
    bitInfo.bmiHeader.biXPelsPerMeter = 0;
    bitInfo.bmiHeader.biYPelsPerMeter = 0;

    // Add header and OPENCV image's data to the HDC
    StretchDIBits(hDCDst, 0, 0,
        winSize.width, winSize.height, 0, 0,
        winSize.width, winSize.height,
        cvImgTmp.data, &bitInfo, DIB_RGB_COLORS, SRCCOPY);

    ReleaseDC( pDC );
}

Answer 1

假设我们有一个 OpenCV 图像 cv::Mat cvImg，应将其转换为 CImage* mfcImg。
当然，MFC 图像应该显示在 MFC 窗口上，即在 CStatic winImg

中

因此，为了在 MFC 窗口中显示 OpenCV 图像，应执行以下转换:

cv::Mat -> CImage -> CStatic

定义MFC窗口大小:

RECT r;
winImg.GetClientRect(&r);
cv::Size winSize(r.right, r.bottom);

cvImg 的大小并不总是与 MFC 窗口的大小相同:

cv::Mat cvImgTmp(winSize, CV_8UC3);
if (cvImg.size() != winSize)
{
    cv::resize(cvImg, cvImgTmp, winSize);
}
else 
{
    cvImgTmp = cvImg.clone();
}

旋转图像:

cv::flip(cvImgTmp, cvImgTmp, 0);

创建 MFC 镜像:

if (mfcImg)
{
    mfcImg->ReleaseDC();
    delete mfcImg; mfcImg = nullptr;
}

mfcImg = new CImage();
mfcImg->Create(winSize.width, winSize.height, 24);

对于mfcImg，您需要一个 header 。使用BITMAPINFO结构创建它

BITMAPINFO bitInfo;
bitInfo.bmiHeader.biBitCount = 24;
bitInfo.bmiHeader.biWidth = winSize.width;
bitInfo.bmiHeader.biHeight = winSize.height;
bitInfo.bmiHeader.biPlanes = 1;
bitInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bitInfo.bmiHeader.biCompression = BI_RGB;
bitInfo.bmiHeader.biClrImportant = 0;
bitInfo.bmiHeader.biClrUsed = 0;
bitInfo.bmiHeader.biSizeImage = 0;
bitInfo.bmiHeader.biXPelsPerMeter = 0;
bitInfo.bmiHeader.biYPelsPerMeter = 0;

将标题和OpenCV图像的数据添加到mfcImg

StretchDIBits(mfcImg->GetDC(), 0, 0,
    winSize.width, winSize.height, 0, 0,
    winSize.width, winSize.height,
    cvImgTmp.data, &bitInfo, DIB_RGB_COLORS, SRCCOPY
);

在MFC窗口中显示mfcImg

mfcImg->BitBlt(::GetDC(winImg.m_hWnd), 0, 0);

如果您不使用mfcImg，请释放它:

if (mfcImg)
{
    mfcImg->ReleaseDC();
    delete mfcImg; mfcImg = nullptr;
}