示例#1
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        /// <summary>
        /// Capture transparent Screenshot of a Window.
        /// </summary>
        /// <param name="Window">The <see cref="Window"/> to Capture.</param>
        /// <param name="IncludeCursor">Whether to include Mouse Cursor.</param>
        public static Bitmap CaptureTransparent(Window Window, bool IncludeCursor = false)
        {
            if (Window == null)
            {
                throw new ArgumentNullException(nameof(Window));
            }

            var backdrop = new Form
            {
                AllowTransparency = true,
                BackColor         = Color.White,
                FormBorderStyle   = FormBorderStyle.None,
                ShowInTaskbar     = false,
                Opacity           = 0
            };

            var r = new RECT();

            const int extendedFrameBounds = 0;

            if (DwmGetWindowAttribute(Window.Handle, extendedFrameBounds, ref r, Marshal.SizeOf <RECT>()) != 0)
            {
                // DwmGetWindowAttribute() failed, usually means Aero is disabled so we fall back to GetWindowRect()
                User32.GetWindowRect(Window.Handle, out r);
            }

            var R = r.ToRectangle();

            // Add a 100px margin for window shadows. Excess transparency is trimmed out later
            R.Inflate(100, 100);

            // This check handles if the window is outside of the visible screen
            R.Intersect(WindowProvider.DesktopRectangle);

            ShowWindow(backdrop.Handle, 4);
            SetWindowPos(backdrop.Handle, Window.Handle,
                         R.Left, R.Top,
                         R.Width, R.Height,
                         SetWindowPositionFlags.NoActivate);
            backdrop.Opacity = 1;
            Application.DoEvents();

            // Capture screenshot with white background
            using (var whiteShot = Capture(R))
            {
                backdrop.BackColor = Color.Black;
                Application.DoEvents();

                // Capture screenshot with black background
                using (var blackShot = Capture(R))
                {
                    backdrop.Dispose();

                    var transparentImage = Extensions.DifferentiateAlpha(whiteShot, blackShot);

                    if (transparentImage == null)
                    {
                        return(null);
                    }

                    if (IncludeCursor)
                    {
                        using (var g = Graphics.FromImage(transparentImage))
                            MouseCursor.Draw(g, P => new Point(P.X - R.X, P.Y - R.Y));
                    }

                    return(transparentImage.CropEmptyEdges());
                }
            }
        }