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

		internal override PaintEventArgs PaintEventStart(ref Message msg, IntPtr handle, bool client) {
			PaintEventArgs	paint_event;
			Hwnd		hwnd;
			Hwnd		paint_hwnd;
			
			// 
			// handle  (and paint_hwnd) refers to the window that is should be painted.
			// msg.HWnd (and hwnd) refers to the window that got the paint message.
			// 
			
			hwnd = Hwnd.ObjectFromHandle(msg.HWnd);
			if (msg.HWnd == handle) {
				paint_hwnd = hwnd;
			} else {
				paint_hwnd = Hwnd.ObjectFromHandle (handle);
			}
	
			if (Caret.Visible == true) {
				Caret.Paused = true;
				HideCaret();
			}

			Graphics dc;

			if (client) {
				dc = Graphics.FromHwnd (paint_hwnd.client_window);

				Region clip_region = new Region ();
				clip_region.MakeEmpty();

				foreach (Rectangle r in hwnd.ClipRectangles) {
					/* Expand the region slightly.
					 * See bug 464464.
					 */
					Rectangle r2 = Rectangle.FromLTRB (r.Left, r.Top, r.Right, r.Bottom + 1);
					clip_region.Union (r2);
				}

				if (hwnd.UserClip != null) {
					clip_region.Intersect(hwnd.UserClip);
				}

				dc.Clip = clip_region;
				paint_event = new PaintEventArgs(dc, hwnd.Invalid);
				hwnd.expose_pending = false;

				hwnd.ClearInvalidArea();

				hwnd.drawing_stack.Push (paint_event);
				hwnd.drawing_stack.Push (dc);

				return paint_event;
			} else {
				dc = Graphics.FromHwnd (paint_hwnd.whole_window);

				if (!hwnd.nc_invalid.IsEmpty) {
					dc.SetClip (hwnd.nc_invalid);
					paint_event = new PaintEventArgs(dc, hwnd.nc_invalid);
				} else {
					paint_event = new PaintEventArgs(dc, new Rectangle(0, 0, hwnd.width, hwnd.height));
				}
				hwnd.nc_expose_pending = false;

				hwnd.ClearNcInvalidArea ();

				hwnd.drawing_stack.Push (paint_event);
				hwnd.drawing_stack.Push (dc);

				return paint_event;
			}
		}