System.Windows.Forms.XplatUIX11.ScrollWindow C# (CSharp) Method

		internal override void ScrollWindow(IntPtr handle, Rectangle area, int XAmount, int YAmount, bool with_children) {
			Hwnd		hwnd;
			IntPtr		gc;
			XGCValues	gc_values;

			hwnd = Hwnd.ObjectFromHandle(handle);

			Rectangle r = Rectangle.Intersect (hwnd.Invalid, area);
			if (!r.IsEmpty) {
				/* We have an invalid area in the window we're scrolling. 
				   Adjust our stored invalid rectangle to to match the scrolled amount */

				r.X += XAmount;
				r.Y += YAmount;

				if (r.X < 0) {
					r.Width += r.X;
					r.X =0;
				}

				if (r.Y < 0) {
					r.Height += r.Y;
					r.Y =0;
				}

				if (area.Contains (hwnd.Invalid))
					hwnd.ClearInvalidArea ();
				hwnd.AddInvalidArea(r);
			}

			gc_values = new XGCValues();

			if (with_children) {
				gc_values.subwindow_mode = GCSubwindowMode.IncludeInferiors;
			}

			gc = XCreateGC(DisplayHandle, hwnd.client_window, IntPtr.Zero, ref gc_values);

			Rectangle visible_rect = GetTotalVisibleArea (hwnd.client_window);
			visible_rect.Intersect (area);

			Rectangle dest_rect = visible_rect;
			dest_rect.Y += YAmount;
			dest_rect.X += XAmount;
			dest_rect.Intersect (area);

			Point src = new Point (dest_rect.X - XAmount, dest_rect.Y - YAmount);
			XCopyArea (DisplayHandle, hwnd.client_window, hwnd.client_window, gc, src.X, src.Y, 
					dest_rect.Width, dest_rect.Height, dest_rect.X, dest_rect.Y);

			Rectangle dirty_area = GetDirtyArea (area, dest_rect, XAmount, YAmount);
			AddExpose (hwnd, true, dirty_area.X, dirty_area.Y, dirty_area.Width, dirty_area.Height);

			ProcessGraphicsExpose (hwnd);

			XFreeGC(DisplayHandle, gc);
		}