在大字体模式下，opencv 桌面捕获 returns 仅 windows 屏幕的一部分

Question

我用这个标准样例用opencv抓屏。如果我在控制面板中的字体大小为 100%，它可以正常工作：

Mat hwnd2mat(HWND hwnd) {
    HDC hwindowDC, hwindowCompatibleDC;
    int height, width, srcheight, srcwidth;
    HBITMAP hbwindow;
    Mat src;
    BITMAPINFOHEADER  bi;
    hwindowDC = GetDC(hwnd);
    hwindowCompatibleDC = CreateCompatibleDC(hwindowDC);
    SetStretchBltMode(hwindowCompatibleDC, COLORONCOLOR);
    RECT windowsize;    // get the height and width of the screen
    GetClientRect(hwnd, &windowsize);
    srcheight = windowsize.bottom;
    srcwidth = windowsize.right;
    height = windowsize.bottom / 1;  //change this to whatever size you want to resize to
    width = windowsize.right / 1;
    src.create(height, width, CV_8UC4);
    // create a bitmap
    hbwindow = CreateCompatibleBitmap(hwindowDC, width, height);
    bi.biSize = sizeof(BITMAPINFOHEADER);    //http://msdn.microsoft.com/en-us/library/windows/window/dd183402%28v=vs.85%29.aspx
    bi.biWidth = width;
    bi.biHeight = -height;  //this is the line that makes it draw upside down or not
    bi.biPlanes = 1;
    bi.biBitCount = 32;
    bi.biCompression = BI_RGB;
    bi.biSizeImage = 0;
    bi.biXPelsPerMeter = 0;
    bi.biYPelsPerMeter = 0;
    bi.biClrUsed = 0;
    bi.biClrImportant = 0;
    SelectObject(hwindowCompatibleDC, hbwindow);
    StretchBlt(hwindowCompatibleDC, 0, 0, width, height, hwindowDC, 0, 0, srcwidth, srcheight, SRCCOPY); //change SRCCOPY to NOTSRCCOPY for wacky colors !
    GetDIBits(hwindowCompatibleDC, hbwindow, 0, height, src.data, (BITMAPINFO *)&bi, DIB_RGB_COLORS);  //copy from hwindowCompatibleDC to hbwindow
    DeleteObject(hbwindow);
    DeleteDC(hwindowCompatibleDC);
    ReleaseDC(hwnd, hwindowDC);
    return src;
}

int main() {
    HWND hwndDesktop = GetDesktopWindow();
    Mat src = hwnd2mat(hwndDesktop);
    imwrite("output.bmp", src);
    return 0;
}

但是如果我启用大字体（至少 Windows 10），那么它只会给我屏幕的左上角：

我该如何解决？

Answer 1

我认为您需要通过创建 corresponding manifest entry 将应用程序标记为支持 HighDpi。否则您的应用程序将处理 DPI 虚拟化。

Answer 2

另一个解决方案可能是在程序开头调用 SetProcessDPIAware()。帮了我。

在大字体模式下，opencv 桌面捕获 returns 仅 windows 屏幕的一部分

opencv desktop capture returns only part of the screen on windows in large fonts mode

c++

winapi

opencv

gdi