private byte[] ScreenCapture(out int length){    length = 0;    if (OperatingSystem.IsWindows())    {        IntPtr hdc = GetDC(IntPtr.Zero);        if (hdc != IntPtr.Zero)        {            using Bitmap source = new Bitmap(GetDeviceCaps(hdc, DESKTOPHORZRES), GetDeviceCaps(hdc, DESKTOPVERTRES));            using (Graphics g = Graphics.FromImage(source))            {                g.CopyFromScreen(0, 0, 0, 0, source.Size, CopyPixelOperation.SourceCopy);                                //绘制鼠标                CURSORINFO pci;                pci.cbSize = Marshal.SizeOf(typeof(CURSORINFO));                if (GetCursorInfo(out pci))                {                    if (pci.flags == CURSOR_SHOWING)                    {                        var hdc1 = g.GetHdc();                        DrawIconEx(hdc1, pci.ptScreenPos.x - 0, pci.ptScreenPos.y - 0, pci.hCursor, 0, 0, 0, IntPtr.Zero, DI_NORMAL);                        g.ReleaseHdc();                    }                }                g.Dispose();            }            ReleaseDC(IntPtr.Zero, hdc);            //转为1/5小图            int newWidth = (int)(source.Width * 0.2);            int newHeight = (int)(source.Height * 0.2);            Bitmap bmp = new Bitmap(newWidth, newHeight);            bmp.SetResolution(source.HorizontalResolution, source.VerticalResolution);            using Graphics graphic = Graphics.FromImage(bmp);            graphic.SmoothingMode = SmoothingMode.HighQuality;            graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;            graphic.DrawImage(source, new Rectangle(0, 0, newWidth, newHeight));            using Image image = bmp;                        //压缩为jpg            using MemoryStream ms = new MemoryStream();            image.Save(ms, ImageFormat.Jpeg);            ms.Seek(0, SeekOrigin.Begin);            length = (int)ms.Length;            byte[] bytes = ArrayPool<byte>.Shared.Rent((int)ms.Length);            ms.Read(bytes);            return bytes;        }    }    return Array.Empty<byte>();}private void Return(byte[] bytes){    ArrayPool<byte>.Shared.Return(bytes);}const int DESKTOPVERTRES = 117;const int DESKTOPHORZRES = 118;[DllImport("user32.dll")]static extern IntPtr GetDC(IntPtr ptr);[DllImport("user32.dll", EntryPoint = "ReleaseDC")]static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDc);[DllImport("gdi32.dll", EntryPoint = "GetDeviceCaps", SetLastError = true)]public static extern int GetDeviceCaps(IntPtr hdc, int nIndex);[DllImport("user32.dll", EntryPoint = "GetSystemMetrics")]private static extern int GetSystemMetrics(int mVal);[StructLayout(LayoutKind.Sequential)]private struct CURSORINFO        {            public Int32 cbSize;            public Int32 flags;            public IntPtr hCursor;            public POINTAPI ptScreenPos;        }[StructLayout(LayoutKind.Sequential)]private struct POINTAPI        {            public int x;            public int y;        }private const Int32 CURSOR_SHOWING = 0x0001;private const Int32 DI_NORMAL = 0x0003;[DllImport("user32.dll")]private static extern bool GetCursorInfo(out CURSORINFO pci);[DllImport("user32.dll", SetLastError = true)]static extern bool DrawIconEx(IntPtr hdc, int xLeft, int yTop, IntPtr hIcon, int cxWidth, int cyHeight, int istepIfAniCur, IntPtr hbrFlickerFreeDraw, int diFlags);