c++ - 循环中的 C++ 窗口图像导致延迟

Question

我正在尝试抓取窗口的图像来抓取像素数据。以下代码段在循环内运行。似乎一切正常，但运行几分钟后，应用程序开始挂起。我的猜测是存在某种内存泄漏。我希望有人能指出我在这里做错了什么。

void ScreenShot(LPCSTR filename)
{
    RECT DesktopParams;
    GetWindowRect(hwnd, &DesktopParams);
    DWORD Width = DesktopParams.right - DesktopParams.left;
    DWORD Height = DesktopParams.bottom - DesktopParams.top;

    DWORD FileSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + (sizeof(RGBTRIPLE) + 1 * (Width*Height * 4));
    char *BmpFileData = (char*)GlobalAlloc(GMEM_FIXED, FileSize);

    PBITMAPFILEHEADER BFileHeader = (PBITMAPFILEHEADER)BmpFileData;
    PBITMAPINFOHEADER  BInfoHeader = (PBITMAPINFOHEADER)&BmpFileData[sizeof(BITMAPFILEHEADER)];

    BFileHeader->bfType = 0x4D42; // BM
    BFileHeader->bfSize = sizeof(BITMAPFILEHEADER);
    BFileHeader->bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);

    BInfoHeader->biSize = sizeof(BITMAPINFOHEADER);
    BInfoHeader->biPlanes = 1;
    BInfoHeader->biBitCount = 24;
    BInfoHeader->biCompression = BI_RGB;
    BInfoHeader->biHeight = Height;
    BInfoHeader->biWidth = Width;

    RGBTRIPLE *Image = (RGBTRIPLE*)&BmpFileData[sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)];
    RGBTRIPLE color;

    HDC CaptureDC = CreateCompatibleDC(DevC);
    HBITMAP CaptureBitmap = CreateCompatibleBitmap(DevC, Width, Height);
    SelectObject(CaptureDC, CaptureBitmap);
    BitBlt(CaptureDC, 0, 0, Width, Height, DevC, 0, 0, SRCCOPY | CAPTUREBLT);
    GetDIBits(CaptureDC, CaptureBitmap, 0, Height, Image, (LPBITMAPINFO)BInfoHeader, DIB_RGB_COLORS);



    RGBTRIPLE *pixel = get_pixel(BInfoHeader, Image, 100, 100);
    cout << (int)pixel->rgbtRed << ", " << (int)pixel->rgbtBlue << "," << (int)pixel->rgbtGreen << endl;
    GlobalFree(BmpFileData);

}

经过更多的测试后，我意识到如果我注释掉 get_pixel，lage 就会消失。

RGBTRIPLE * get_pixel(PBITMAPINFOHEADER  BInfoHeader, RGBTRIPLE *Image, int x, int y)
{
    return &Image[(BInfoHeader->biHeight - 1 - y)*BInfoHeader->biWidth + x];
}

标签： c++winapi