windows取窗口rgb数据

HDC srcHdc = GetDC(This->hwnd_);
    HDC destHdc = CreateCompatibleDC(srcHdc);
    //HBITMAP destBitmap = CreateCompatibleBitmap(srcHdc, 128, 128);

    BITMAPINFO bitmapInfo;
    ZeroMemory(&bitmapInfo, sizeof(BITMAPINFO));
    bitmapInfo.bmiHeader.biSize = sizeof(BITMAPINFO);
    bitmapInfo.bmiHeader.biWidth = 256;
    bitmapInfo.bmiHeader.biHeight = -256;    //>0倒立, <0正立,bmp格式数据位倒立.
    bitmapInfo.bmiHeader.biPlanes = 1;
    bitmapInfo.bmiHeader.biBitCount = 24;
    char *lpBitmapBits = 0;
    HBITMAP destBitmap = CreateDIBSection(srcHdc, &bitmapInfo,
        DIB_RGB_COLORS, (void **)&lpBitmapBits, NULL, 0);
    SelectObject(destHdc, destBitmap);
    BitBlt(destHdc,0,0,256,256,srcHdc,100,100,SRCCOPY);

    数据首地址lpBitmapBits