Other Root Window Messages



Pagers wanting to close a window MUST send a _NET_CLOSE_WINDOW client message request to the root window:

  window = window to close
  message_type = _NET_CLOSE_WINDOW
  format = 32
  data.l[0] = timestamp
  data.l[1] = source indication
  other data.l[] elements = 0

The Window Manager MUST then attempt to close the window specified. See the section called “Source indication in requests” for details on the source indication.

Rationale: A Window Manager might be more clever than the usual method (send WM_DELETE message if the protocol is selected, XKillClient otherwise). It might introduce a timeout, for example. Instead of duplicating the code, the Window Manager can easily do the job.


  window = window to be moved or resized
  message_type = _NET_MOVERESIZE_WINDOW
  format = 32
  data.l[0] = gravity and flags 
  data.l[1] = x 
  data.l[2] = y
  data.l[3] = width
  data.l[4] = height

The low byte of data.l[0] contains the gravity to use; it may contain any value allowed for the WM_SIZE_HINTS.win_gravity property: NorthWest (1), North (2), NorthEast (3), West (4), Center (5), East (6), SouthWest (7), South (8), SouthEast (9) and Static (10). A gravity of 0 indicates that the Window Manager should use the gravity specified in WM_SIZE_HINTS.win_gravity. The bits 8 to 11 indicate the presence of x, y, width and height. The bits 12 to 15 indicate the source (see the section called “Source indication in requests”), so 0001 indicates the application and 0010 indicates a Pager or a Taskbar. The remaining bits should be set to zero.

Pagers wanting to move or resize a window may send a _NET_MOVERESIZE_WINDOW client message request to the root window instead of using a ConfigureRequest.

Window Managers should treat a _NET_MOVERESIZE_WINDOW message exactly like a ConfigureRequest (in particular, adhering to the ICCCM rules about synthetic ConfigureNotify events), except that they should use the gravity specified in the message.

Rationale: Using a _NET_MOVERESIZE_WINDOW message with StaticGravity allows Pagers to exactly position and resize a window including its decorations without knowing the size of the decorations.


  window = window to be moved or resized
  message_type = _NET_WM_MOVERESIZE
  format = 32
  data.l[0] = x_root 
  data.l[1] = y_root
  data.l[2] = direction
  data.l[3] = button
  data.l[4] = source indication

This message allows Clients to initiate window movement or resizing. They can define their own move and size "grips", whilst letting the Window Manager control the actual operation. This means that all moves/resizes can happen in a consistent manner as defined by the Window Manager. See the section called “Source indication in requests” for details on the source indication.

When sending this message in response to a button press event, button SHOULD indicate the button which was pressed, x_root and y_root MUST indicate the position of the button press with respect to the root window and direction MUST indicate whether this is a move or resize event, and if it is a resize event, which edges of the window the size grip applies to. When sending this message in response to a key event, the direction MUST indicate whether this this is a move or resize event and the other fields are unused.

#define _NET_WM_MOVERESIZE_SIZE_TOP          1
#define _NET_WM_MOVERESIZE_SIZE_LEFT         7
#define _NET_WM_MOVERESIZE_MOVE              8   /* movement only */
#define _NET_WM_MOVERESIZE_SIZE_KEYBOARD     9   /* size via keyboard */
#define _NET_WM_MOVERESIZE_MOVE_KEYBOARD    10   /* move via keyboard */
#define _NET_WM_MOVERESIZE_CANCEL           11   /* cancel operation */

The Client MUST release all grabs prior to sending such message (except for the _NET_WM_MOVERESIZE_CANCEL message).

The Window Manager can use the button field to determine the events on which it terminates the operation initiated by the _NET_WM_MOVERESIZE message. Since there is a race condition between a client sending the _NET_WM_MOVERESIZE message and the user releasing the button, Window Managers are advised to offer some other means to terminate the operation, e.g. by pressing the ESC key. The special value _NET_WM_MOVERESIZE_CANCEL also allows clients to cancel the operation by sending such message if they detect the release themselves (clients should send it if they get the button release after sending the move resize message, indicating that the WM did not get a grab in time to get the release).



Pagers wanting to restack a window SHOULD send a _NET_RESTACK_WINDOW client message request to the root window:

  window = window to restack
  message_type = _NET_RESTACK_WINDOW
  format = 32
  data.l[0] = source indication
  data.l[1] = sibling window
  data.l[2] = detail
  other data.l[] elements = 0

This request is similar to ConfigureRequest with CWSibling and CWStackMode flags. It should be used only by pagers, applications can use normal ConfigureRequests. The source indication field should be therefore set to 2, see the section called “Source indication in requests” for details.

Rationale: A Window Manager may put restrictions on configure requests from applications, for example it may under some conditions refuse to raise a window. This request makes it clear it comes from a pager or similar tool, and therefore the Window Manager should always obey it.


  window = window for which to set _NET_FRAME_EXTENTS

A Client whose window has not yet been mapped can request of the Window Manager an estimate of the frame extents it will be given upon mapping. To retrieve such an estimate, the Client MUST send a _NET_REQUEST_FRAME_EXTENTS message to the root window. The Window Manager MUST respond by estimating the prospective frame extents and setting the window's _NET_FRAME_EXTENTS property accordingly. The Client MUST handle the resulting _NET_FRAME_EXTENTS PropertyNotify event. So that the Window Manager has a good basis for estimation, the Client MUST set any window properties it intends to set before sending this message. The Client MUST be able to cope with imperfect estimates.

Rationale: A client cannot calculate the dimensions of its window's frame before the window is mapped, but some toolkits need this information. Asking the window manager for an estimate of the extents is a workable solution. The estimate may depend on the current theme, font sizes or other window properties. The client can track changes to the frame's dimensions by listening for _NET_FRAME_EXTENTS PropertyNotify events.