Windows API 截屏，并转换成cv::Mat

抓取当前屏幕函数

void Screen() {
    //创建画板
    HDC hScreen	= CreateDC("DISPLAY", NULL, NULL, NULL);
    HDC	hCompDC	= CreateCompatibleDC(hScreen);

    //取屏幕宽度和高度
    int nWidth = GetSystemMetrics(SM_CXSCREEN);
    int nHeight = GetSystemMetrics(SM_CYSCREEN);

    //创建Bitmap对象
    hBmp = CreateCompatibleBitmap(hScreen, nWidth, nHeight);
    hOld = (HBITMAP)SelectObject(hCompDC, hBmp);
    BitBlt(hCompDC, 0, 0, nWidth, nHeight, hScreen, 0, 0, SRCCOPY);
    SelectObject(hCompDC, hOld);

    //释放对象
    DeleteDC(hScreen);
    DeleteDC(hCompDC);	
}

把HBITMAP型转成Mat型

BOOL HBitmapToMat(HBITMAP& _hBmp,Mat& _mat) {
    //BITMAP操作
    BITMAP bmp;
    GetObject(_hBmp,sizeof(BITMAP),&bmp);
    int nChannels = bmp.bmBitsPixel == 1 ? 1 : bmp.bmBitsPixel/8 ;
    int depth = bmp.bmBitsPixel == 1 ? IPL_DEPTH_1U : IPL_DEPTH_8U;

    //mat操作
    Mat v_mat;
    v_mat.create(cvSize(bmp.bmWidth,bmp.bmHeight), CV_MAKETYPE(CV_8U,nChannels));
    GetBitmapBits(_hBmp,bmp.bmHeight*bmp.bmWidth*nChannels,v_mat.data);
    _mat=v_mat;
    return TRUE;   
}