[twobob]

http://standards.freedesktop.org/wm-...html#id2578152
_NET_WM_STATE notes...

Spoiler:

_NET_WM_STATE

_NET_WM_STATE, ATOM[]
A list of hints describing the window state. Atoms present in the list MUST be considered set, atoms not present in the list MUST be considered not set. The Window Manager SHOULD honor _NET_WM_STATE whenever a withdrawn window requests to be mapped. A Client wishing to change the state of a window MUST send a _NET_WM_STATE client message to the root window (see below). The Window Manager MUST keep this property updated to reflect the current state of the window.

The Window Manager should remove the property whenever a window is withdrawn, but it should leave the property in place when it is shutting down, e.g. in response to losing ownership of the WM_Sn manager selection.

Rationale: Removing the property upon window withdrawal helps legacy applications which want to reuse withdrawn windows. Not removing the property upon shutdown allows the next Window Manager to restore windows to their previous state.

Possible atoms are:

_NET_WM_STATE_MODAL, ATOM
_NET_WM_STATE_STICKY, ATOM
_NET_WM_STATE_MAXIMIZED_VERT, ATOM
_NET_WM_STATE_MAXIMIZED_HORZ, ATOM
_NET_WM_STATE_SHADED, ATOM
_NET_WM_STATE_SKIP_TASKBAR, ATOM
_NET_WM_STATE_SKIP_PAGER, ATOM
_NET_WM_STATE_HIDDEN, ATOM
_NET_WM_STATE_FULLSCREEN, ATOM
_NET_WM_STATE_ABOVE, ATOM
_NET_WM_STATE_BELOW, ATOM
_NET_WM_STATE_DEMANDS_ATTENTION, ATOM
_NET_WM_STATE_FOCUSED, ATOM
An implementation MAY add new atoms to this list. Implementations without extensions MUST ignore any unknown atoms, effectively removing them from the list. These extension atoms MUST NOT start with the prefix _NET.

_NET_WM_STATE_MODAL indicates that this is a modal dialog box. If the WM_TRANSIENT_FOR hint is set to another toplevel window, the dialog is modal for that window; if WM_TRANSIENT_FOR is not set or set to the root window the dialog is modal for its window group.

_NET_WM_STATE_STICKY indicates that the Window Manager SHOULD keep the window's position fixed on the screen, even when the virtual desktop scrolls.

_NET_WM_STATE_MAXIMIZED_{VERT,HORZ} indicates that the window is {vertically,horizontally} maximized.

_NET_WM_STATE_SHADED indicates that the window is shaded.

_NET_WM_STATE_SKIP_TASKBAR indicates that the window should not be included on a taskbar. This hint should be requested by the application, i.e. it indicates that the window by nature is never in the taskbar. Applications should not set this hint if _NET_WM_WINDOW_TYPE already conveys the exact nature of the window.

_NET_WM_STATE_SKIP_PAGER indicates that the window should not be included on a Pager. This hint should be requested by the application, i.e. it indicates that the window by nature is never in the Pager. Applications should not set this hint if _NET_WM_WINDOW_TYPE already conveys the exact nature of the window.

_NET_WM_STATE_HIDDEN should be set by the Window Manager to indicate that a window would not be visible on the screen if its desktop/viewport were active and its coordinates were within the screen bounds. The canonical example is that minimized windows should be in the _NET_WM_STATE_HIDDEN state. Pagers and similar applications should use _NET_WM_STATE_HIDDEN instead of WM_STATE to decide whether to display a window in miniature representations of the windows on a desktop.

Implementation note: if an Application asks to toggle _NET_WM_STATE_HIDDEN the Window Manager should probably just ignore the request, since _NET_WM_STATE_HIDDEN is a function of some other aspect of the window such as minimization, rather than an independent state.

_NET_WM_STATE_FULLSCREEN indicates that the window should fill the entire screen and have no window decorations. Additionally the Window Manager is responsible for restoring the original geometry after a switch from fullscreen back to normal window. For example, a presentation program would use this hint.

_NET_WM_STATE_ABOVE indicates that the window should be on top of most windows (see the section called “Stacking order” for details).

_NET_WM_STATE_BELOW indicates that the window should be below most windows (see the section called “Stacking order” for details).

_NET_WM_STATE_ABOVE and _NET_WM_STATE_BELOW are mainly meant for user preferences and should not be used by applications e.g. for drawing attention to their dialogs (the Urgency hint should be used in that case, see the section called “Urgency”).'

_NET_WM_STATE_DEMANDS_ATTENTION indicates that some action in or with the window happened. For example, it may be set by the Window Manager if the window requested activation but the Window Manager refused it, or the application may set it if it finished some work. This state may be set by both the Client and the Window Manager. It should be unset by the Window Manager when it decides the window got the required attention (usually, that it got activated).

_NET_WM_STATE_FOCUSED indicates whether the window's decorations are drawn in an active state. Clients MUST regard it as a read-only hint. It cannot be set at map time or changed via a _NET_WM_STATE client message. The window given by _NET_ACTIVE_WINDOW will usually have this hint, but at times other windows may as well, if they have a strong association with the active window and will be considered as a unit with it by the user. Clients that modify the appearance of internal elements when a toplevel has keyboard focus SHOULD check for the availability of this state in _NET_SUPPORTED and, if it is available, use it in preference to tracking focus via FocusIn events. By doing so they will match the window decorations and accurately reflect the intentions of the Window Manager.

To change the state of a mapped window, a Client MUST send a _NET_WM_STATE client message to the root window:

window = the respective client window
message_type = _NET_WM_STATE
format = 32
data.l[0] = the action, as listed below
data.l[1] = first property to alter
data.l[2] = second property to alter
data.l[3] = source indication
other data.l[] elements = 0
This message allows two properties to be changed simultaneously, specifically to allow both horizontal and vertical maximization to be altered together. l[2] MUST be set to zero if only one property is to be changed. See the section called “Source indication in requests” for details on the source indication. l[0], the action, MUST be one of:

_NET_WM_STATE_REMOVE 0 /* remove/unset property */
_NET_WM_STATE_ADD 1 /* add/set property */
_NET_WM_STATE_TOGGLE 2 /* toggle property */
See also the implementation notes on urgency and fixed size windows.