在MFCC ++中捕获并保存窗口的屏幕截图

问题描述

我想在MFC中捕获窗口的屏幕截图并将其另存为图像文件。在这些示例之后，我得到了如下内容

OnSave()
{
    CRect rect;
    GetwindowRect(&rect);
    CImage* img = new CImage();
    img->Create(rect.Width(),rect.Height(),32);
    HDC device_context_handle = img->GetDC();
    HWND hwnd = this->GetSafeHwnd();
    bool IsPrint =::Printwindow(hwnd,device_context_handle,PW_CLIENTONLY);
    HRESULT res = img->Save(L"image12.bmp",Gdiplus::ImageFormatBMP);
    img->ReleaseDC();

    delete img;
}

这样做，我得到了具有正确尺寸的文件，但是它始终是黑色的。我检查了一下，结果保存（res）也始终为0。我尝试在线检查其他示例，但无法解决此黑色图像问题。是否有修改建议或以其他方式进行修改？

解决方法

应该像下面这样

    int x1,y1,x2,y2,w,h;

    // get window dimensions for following vars.
    // Don.t know if you want all area or just client area,// so use GetClientRect or GetWindowRect accordingly.
    // These functions sometimes are not so obvious on what they do.
    x1 = /**/;
    y1 = /**/;
    x2 = /**/;
    y2 = /**/;

    // width and height
    w = x2 - x1;
    h = y2 - y1;

    // copy window to bitmap
    HDC     hWindow = (HDC) window.GetDC();
    HDC     hDC = CreateCompatibleDC(hWindow);
    HBITMAP hBitmap = CreateCompatibleBitmap(hWindow,h);
    HGDIOBJ old_obj = SelectObject(hDC,hBitmap);
    BOOL    bRet = BitBlt(hDC,h,hWindow,x1,SRCCOPY);
    
    CImage image;
    image.Attach(hBitmap);
    image.Save(debug_dir + L"window.bmp",Gdiplus::ImageFormatBMP);

    // clean-up
    SelectObject(hDC,old_obj);
    DeleteDC(hDC);
    ::ReleaseDC(NULL,hWindow);
    DeleteObject(hBitmap);