Subject: Re: bug#745: pop-to-buffer, frames, and input focus

From: Helmut Eller <[email-masked]>
Date: Fri, 29 Aug 2008 17:02:54 +0200

* martin rudalics [2008-08-29 11:26+0200] writes:

>> Emacs could first test whether the window manager is EWMH compliant
>
> How?  Emacs can't even test whether the window manager is click to focus
> or focus follows mouse.

xterm.c:wm_supports implements the test already.  By inspecting the
_NET_SUPPORTED property on the root window.  A compliant window manager
must enumerate the supported features there.

See http://standards.freedesktop.org/wm-spec/1.4/ar01s03.html#id2523263.

E.g. for Sawfish I get

shell$ xprop _NET_SUPPORTED
_NET_SUPPORTED(ATOM) = _NET_ACTIVE_WINDOW, _NET_CLIENT_LIST,
_NET_CLIENT_LIST_STACKING, _NET_CLOSE_WINDOW, _NET_CURRENT_DESKTOP,
_NET_DESKTOP_GEOMETRY, _NET_DESKTOP_NAMES, _NET_DESKTOP_VIEWPORT,
_NET_NUMBER_OF_DESKTOPS, _NET_PROTOCOLS, _NET_SHOWING_DESKTOP,
_NET_SUPPORTED, _NET_SUPPORTING_WM_CHECK, _NET_WORKAREA,
_NET_WM_DESKTOP, _NET_WM_ICON_GEOMETRY, _NET_WM_MOVERESIZE,
_NET_WM_MOVERESIZE_MOVE, _NET_WM_MOVERESIZE_SIZE_BOTTOM,
_NET_WM_MOVERESIZE_SIZE_BOTTOMLEFT, _NET_WM_MOVERESIZE_SIZE_BOTTOMRIGHT,
_NET_WM_MOVERESIZE_SIZE_LEFT, _NET_WM_MOVERESIZE_SIZE_RIGHT,
_NET_WM_MOVERESIZE_SIZE_TOP, _NET_WM_MOVERESIZE_SIZE_TOPLEFT,
_NET_WM_MOVERESIZE_SIZE_TOPRIGHT, _NET_WM_MOVERESIZE_SIZE_KEYBOARD,
_NET_WM_MOVERESIZE_MOVE_KEYBOARD, _NET_WM_PING, _NET_WM_STATE,
_NET_WM_STATE_ABOVE, _NET_WM_STATE_ADD, _NET_WM_STATE_BELOW,
_NET_WM_STATE_FULLSCREEN, _NET_WM_STATE_MAXIMIZED,
_NET_WM_STATE_MAXIMIZED_HORZ, _NET_WM_STATE_MAXIMIZED_VERT,
_NET_WM_STATE_REMOVE, _NET_WM_STATE_SHADED, _NET_WM_STATE_SKIP_PAGER,
_NET_WM_STATE_SKIP_TASKBAR, _NET_WM_STATE_STICKY, _NET_WM_STATE_TOGGLE,
_NET_WM_STRUT, _NET_WM_WINDOW_TYPE, _NET_WM_WINDOW_TYPE_DESKTOP,
_NET_WM_WINDOW_TYPE_DIALOG, _NET_WM_WINDOW_TYPE_DOCK,
_NET_WM_WINDOW_TYPE_TOOLBAR, _NET_WM_WINDOW_TYPE_MENU,
_NET_WM_WINDOW_TYPE_UTILITY, _NET_WM_WINDOW_TYPE_SPLASH

>> I also found the gtk_window_set_focus_on_map function.  This seems to
>> rely on the _NET_WM_USER_TIME EWMH.  Sawfish ignores _NET_WM_USER_TIME,
>> but it could be useful for other window managers.
>
> And this would have to be supplied by the user separately.  Or is there
> some way to get such basic information from window-managers?

For a window manager which supports it, _NET_SUPPORTED will contain
_NET_WM_USER_TIME.  But it wouldn't hurt to set _NET_WM_USER_TIME to 0,
because that should be interpreted as "disable focus-on-map".  At least
gtk_window_set_focus_on_map sets the property unconditionally.

Helmut.