Ubuntu Manpage: X11::Protocol::WM -- window manager things for client programs

Provided by: libx11-protocol-other-perl_28-1_all

NAME

       X11::Protocol::WM -- window manager things for client programs

SYNOPSIS

        use X11::Protocol::WM;

DESCRIPTION

       This is some window manager related functions for use by client programs, as per the "Inter-Client
       Communication Conventions Manual" and some of the Net-WM "Extended Window Manager Hints".

           /usr/share/doc/xorg-docs/specs/ICCCM/icccm.txt.gz

           <http://www.freedesktop.org/wiki/Specifications/wm-spec>

   Usual Properties
       Every toplevel client window should usually

       •   "set_wm_class()" to identify itself to other programs (see "WM_CLASS").

       •   "set_wm_name()"   and   "set_wm_icon_name()"   for   user-visible   identification   (see   "WM_NAME,
           WM_ICON_NAME").

       •   "set_wm_client_machine_from_syshostname()"  and  "set_net_wm_pid()"  for  the  running  process  (see
           "WM_CLIENT_MACHINE" and "_NET_WM_PID").

       Then optionally,

       •   If you have an icon image then "set_wm_hints()" with a bitmap or a window (see "WM_HINTS").

       •   If  the  user gave an initial size or position on the command line then "set_wm_normal_hints()".  The
           same if the program has min/max sizes or aspect ratio desired (see "WM_NORMAL_HINTS").

       •   If a command to re-run the program can be constructed then "set_wm_command()",  and  preferably  keep
           that up-to-date with changes such as currently open file etc (see "WM_COMMAND").

FUNCTIONS

Text Properties
Property functions taking text strings such as "set_wm_name()" accept either byte strings or Perl 5.8
wide char strings. Byte strings in 5.8 and all strings in earlier Perl are presumed to be Latin-1 and
set as "STRING" type in properties. Perl 5.8 wide char strings are stored as "STRING" if entirely
Latin-1, or encoded to "COMPOUND_TEXT" for other chars (see Encode::X11).

In the future perhaps the string functions could accept some sort of compound text object to represent
segments of various encodings to become "COMPOUND_TEXT", together with manipulations for such content
etc. If text is bytes in one of the ICCCM encodings then it might save some work to represent it
directly as "COMPOUND_TEXT" segments rather than going to wide chars and back again.

"set_text_property ($X, $window, $prop, $str)"
Set the given $prop (integer atom) property on $window (integer XID) using either "STRING" or
"COMPOUND_TEXT" as described above. If $str is "undef" then $prop is deleted.

$str is limited to "$X->maximum_request_length()". There's no attempt to store very long strings
piecewise. The protocol makes this limit at least 16384 bytes and the server may allow more,
possibly much more.

WM_CLASS
"X11::Protocol::WM::set_wm_class ($X, $window, $instance, $class)"
Set the "WM_CLASS" property on $window (an XID).

This property may be used by the window manager to lookup settings and preferences for the program
through the X Resource system (see "RESOURCES" in X(7)) or similar.

Usually the instance name is the program command such as "xterm" and the class name something like
"XTerm". Some programs have command line options to set the class and/or instance so the user can
have different window manager settings applied to a particular running copy of a program.

X11::Protocol::WM::set_wm_class ($X, $window,
"myprog", "MyProg");

$instance and $class must be ASCII or Latin-1 only. Perl 5.8 wide-char strings which are Latin-1 are
converted as necessary.

WM_CLIENT_MACHINE
"X11::Protocol::WM::set_wm_client_machine ($X, $window, $hostname)"
Set the "WM_CLIENT_MACHINE" property on $window to $hostname (a string).

$hostname should be the name of the client machine as seen from the server. If $hostname is "undef"
then the property is deleted.

Usually a machine name is ASCII-only, but anything per "Text Properties" above is accepted.

"X11::Protocol::WM::set_wm_client_machine_from_syshostname ($X, $window)"
Set the "WM_CLIENT_MACHINE" property on $window using the Sys::Hostname module.

If "Sys::Hostname" can't determine a hostname by its various gambits then currently the property is
deleted. Would it be better to leave it unchanged, or return a flag to say if set?

Some of the "Sys::Hostname" cases might return "localhost". That's put through unchanged, on the
assumption that it would be when there's no networking beyond the local host so client and server are
always on the same machine and name "localhost" suffices.

WM_COMMAND
"X11::Protocol::WM::set_wm_command ($X, $window, $command, $arg...)"
Set the "WM_COMMAND" property on $window (an XID).

This should be a program name and argument strings which will restart the client. $command is the
program name, followed by any argument strings.

X11::Protocol::WM::set_wm_command ($X, $window,
'myprog',
'--option',
'filename.txt');

A client can set this at any time, or if participating in the "WM_SAVE_YOURSELF" session manager
protocol then it should set in response to a "WM_SAVE_YOURSELF" "ClientMessage".

The command should start the client in its current state as far as possible, so the command might
include a filename, command line options for current settings, etc.

Non-ASCII is allowed per "Text Properties" above. The ICCCM spec is for Latin-1 to work on a POSIX
Latin-1 system, but how well anything else survives a session manager etc is another matter.

WM_ICON_SIZE
"($min_width,$min_height, $max_width,$max_height, $width_inc,$height_inc) =
X11::Protocol::WM::get_wm_icon_size($X,$root)"
Return the window manager's "WM_ICON_SIZE" recommended icon sizes (in pixels) as a range, and
increment above the minimum. If there's no "WM_ICON_SIZE" property then return an empty list.

$root is the root window to read. If omitted then read the "$X->root" default.

An icon pixmap or window in "WM_HINTS" should be a size in this range. Many window managers don't
set a preferred icon size. 32x32 might be typical on a small screen or 48x48 on a bigger screen.

WM_HINTS
"X11::Protocol::WM::set_wm_hints ($X, $window, key=>value, ...)"
Set the "WM_HINTS" property on $window (an XID). For example,

X11::Protocol::WM::set_wm_hints
($X, $my_window,
input => 1,
initial_state => 'NormalState',
icon_pixmap => $my_pixmap);

The key/value parameters are as follows.

input integer 0 or 1
initial_state enum string or number
icon_pixmap pixmap (XID integer), depth 1
icon_window window (XID integer)
icon_x \ integer coordinate
icon_y / integer coordinate
icon_mask pixmap (XID integer)
window_group window (XID integer)
urgency boolean

"input" is 1 if the client wants the window manager to give $window the keyboard input focus. This
will be with "$X->SetInputFocus()", or if "WM_TAKE_FOCUS" is in "WM_PROTOCOLS" then instead by a
"ClientMessage".

"input" is 0 if the window manager should not give the client the focus. This is either because
$window is output-only, or if "WM_TAKE_FOCUS" is in "WM_PROTOCOLS" then because the client will do a
"SetInputFocus()" to itself on an appropriate button press etc.

"initial_state" is a string or number. The ICCCM allows "NormalState" or "IconicState" as initial
states.

"NormalState" 1
"IconicState" 3

"icon_pixmap" should be a pixmap (an XID) with depth 1, ie. a bitmap. The window manager will draw
it in suitable contrasting colours. "1" pixels are foreground and "0" is background. "icon_mask"
bitmap is applied to the displayed icon. It can be used to make a non-rectangular icon.

"icon_window" is a window which the window manager may show when $window is iconified. This can be
used for a multi-colour icon, either by a background or by client drawing (in response to "Expose"
events, or updated periodically for a clock, etc). The window should be a child of the root and
should use the default visual and colormap of the screen. The window manager might resize the window
and/or border.

The window manager might set a "WM_ICON_SIZE" property on the root window for good icon sizes. See
"WM_ICON_SIZE".

"window_group" is the XID of a window which is the group leader of a group of top-level windows being
used by the client. The window manager might provide a way to manipulate the group as a whole, for
example to iconify it all. If iconified then the icon hints of the leader are used for the icon.
The group leader can be an unmapped window. It can be convenient to use a never-mapped window as the
leader for all subsequent windows.

"urgency" true means the window is important and the window manager should draw the user's attention
to it in some way. The client can change this hint at any time to change the current importance.

"(key => $value, ...) = X11::Protocol::WM::get_wm_hints ($X, $window)"
Return the "WM_HINTS" property from $window. The return is a list of key/value pairs as per
"set_wm_hints()" above

input => 1,
icon_pixmap => 1234,
...

Only fields with their flag bits set in the hints are included in the return. If there's no
"WM_HINTS" at all or or its flags field is zero then the return is an empty list.

The return can be put into a hash to get fields by name,

my %hints = X11::Protocol::WM::get_wm_hints ($X, $window);
if (exists $hints{'icon_pixmap'}) {
print "icon_pixmap is ", $hints{'icon_pixmap'}, "\n";
}

"initial_state" is a string such as "NormalState". The pixmaps and windows are string "None" if set
but zero (which is probably unusual). If "$X->{'do_interp'}" is disabled then all are numbers.

X11R2 Xlib had a bug in its "XSetWMHints()" which chopped off the "window_group" value from the hints
stored. The "window_group" field is omitted from the return in that case.

"(key => $value, ...) = X11::Protocol::WM::change_wm_hints ($X, $window, key=>value, ...)"
Change some fields of the "WM_HINTS" property on $window. The given key/value fields are changed.
Other fields are left alone. For example,

X11::Protocol::WM::set_wm_hints ($X, $window,
urgency => 1);

A value "undef" means delete a field,

X11::Protocol::WM::set_wm_hints ($X, $window,
icon_pixmap => undef,
icon_mask => undef);

The change requires a server round-trip to fetch the current values from $window. An application
might prefer to remember its desired hints and send a full "set_wm_hints()" each time.

"$bytes = X11::Protocol::WM::pack_wm_hints ($X, key=>value...)"
Pack a set of values into a byte string of "WM_HINTS" format. The key/value arguments are per
"set_wm_hints()" above and the result is the raw bytes stored in a "WM_HINTS" property.

The $X argument is not actually used currently, but is present in case "initial_state" or other
values might use an "$X->num()" lookup in the future.

"(key => $value, ...) = X11::Protocol::WM::unpack_wm_hints ($X, $bytes)"
Unpack a byte string as a "WM_HINTS" structure. The return is key/value pairs as per
"get_wm_hints()" above. The $X parameter is used for "do_interp". There's no communication with the
server.

WM_NAME, WM_ICON_NAME
"X11::Protocol::WM::set_wm_name ($X, $window, $name)"
Set the "WM_NAME" property on $window (an integer XID) to $name (a string).

The window manager might display this as a title above the window, or in a menu of windows, etc. It
can be a Perl 5.8 wide-char string per "Text Properties" above. A good window manager ought to
support non-ASCII or non-Latin-1 titles, but how well it displays might depend on fonts etc.

"X11::Protocol::WM::set_wm_icon_name ($X, $window, $name)"
Set the "WM_ICON_NAME" property on $window (an integer XID) to $name (a string).

The window manager might display this when $window is iconified. If $window doesn't have an icon (in
"WM_HINTS" or from the window manager itself) then this text might be all that's shown. Either way
it should be something short. It can be a Perl 5.8 wide-char string per "Text Properties" above.

WM_NORMAL_HINTS
"X11::Protocol::WM::set_wm_normal_hints ($X, $window, key=>value,...)"
Set the "WM_NORMAL_HINTS" property on $window (an integer XID). This is a "WM_SIZE_HINTS" structure
which tells the window manager what sizes the client would like. For example,

set_wm_normal_hints ($X, $window,
min_width => 200,
min_height => 100);

Generally the window manager restricts user resizing to the hint limits. Most window managers use
these hints, but of course they're only hints and a good program should be prepared for other sizes
even if it won't look good or can't do much useful when too big or too small etc.

The key/value parameters are

user_position boolean, window x,y is user specified
user_size boolean, window width,height is user specified
program_position boolean, window x,y is program specified
program_size boolean, window width,height is program specified
min_width \ integers, min size in pixels
min_height /
max_width \ integers, max size in pixels
max_height /
base_width \ integers, size base in pixels
base_height /
width_inc \ integers, size increment in pixels
height_inc /
min_aspect \ fraction 2/3 or decimal 2 or 1.5
min_aspect_num | or integer num/den up to 0x7FFFFFFF
min_aspect_den |
max_aspect |
max_aspect_num |
max_aspect_den /
win_gravity WinGravity enum "NorthEast" etc

"user_position" and "user_size" are flags meaning that the window's x,y or width,height (in the usual
core "$X->SetWindowAttributes()") were given by the user, for example from a "-geometry" command line
option. The window manager will generally obey these values and skip any auto-placement or
interactive placement it might otherwise do.

"program_position" and "program_size" are flags meaning the window x,y or width,height were
calculated by the program. The window manager might override with its own positioning or sizing
policy. There's generally no need to set these fields unless the program has a definite idea of
where and how big it should be. For a size it's enough to set the core window width,height and let
the window manager (if there's one running) go from there.

Items shown grouped above must be given together, so for instance if a "min_width" is given then
"min_height" should be given too.

"base_width","base_height" and "width_inc","height_inc" ask that the window be a certain base size in
pixels then a multiple of "inc" pixels above that. This can be used by things like "xterm" which
want a fixed size for border or scrollbar and then a multiple of the character size above that. If
"base_width","base_height" are not given then "min_width","min_height" is the base size.

"base_width","base_height" can be smaller than "min_width","min_height". This means the size should
still be a base+inc multiple, but the first such which is at least the min size. The window manager
generally presents the "inc" multiple to the user, so that for example on an xterm the user sees a
count of characters. A min size can then demand for example a minimum 1x1 or 2x2 character size.

"min_aspect","max_aspect" ask that the window have a certain minimum or maximum width/height ratio.
For example aspect 2/1 means it should be twice as wide as it is high. This is applied to the size
above "base_width","base_height", or if base not given then to the whole window size.

"min_aspect_num","min_aspect_den" and "max_aspect_num","max_aspect_den" set numerator and denominator
values directly (INT32, so maximum 0x7FFF_FFFF). Or "min_aspect" and "max_aspect" accept a single
value in various forms which are turned into num/den values.

2 integer
1.125 decimal, meaning 1125/1000
2/3 fraction
1.5/4.5 fraction with decimals

Values bigger than 0x7FFFFFFF in these forms are reduced proportionally as necessary. A Perl
floating point value will usually have more bits of precision than 0x7FFFFFFF and is truncated to
something that fits.

"win_gravity" is how the client would like to be shifted to make room for any surrounding frame the
window manager might add. For example if the program calculated the window size and position to
ensure the north-east corner is at a desired position, then give "win_gravity => "NorthEast"" so that
the window manager keeps the north-east corner the same when it applies its frame.

"win_gravity => "Static"" means the frame is put around the window and the window not moved at all.
Of course that might mean some of the frame ends up off-screen.

"$bytes = X11::Protocol::WM::pack_size_hints ($X, key=>value,...)"
Return a bytes string which is a "WM_SIZE_HINTS" structure made from the given key/value parameters.
"WM_SIZE_HINTS" is structure type for "WM_NORMAL_HINTS" described above and the key/value parameters
are as described above.

The $X parameter is used to interpret "win_gravity" enum values. There's no communication with the
server.

"($num,$den) = X11::Protocol::WM::aspect_to_num_den ($aspect)"
Return a pair of INT32 integers 0 to 0x7FFF_FFFF for the given aspect ratio $aspect. This is the
conversion applied to "min_aspect" and "max_aspect" above. $aspect can be any of the integer,
decimal or fraction described.

WM_PROTOCOLS
"X11::Protocol::WM::set_wm_protocols ($X, $window, $protocol,...)"
Set the "WM_PROTOCOLS" property on $window (an XID). Each argument is a string protocol name or an
integer atom ID.

X11::Protocol::WM::set_wm_protocols
($X, $window, 'WM_DELETE_WINDOW', '_NET_WM_PING')

For example "WM_DELETE_WINDOW" means that when the user clicks the close button the window manager
sends a "ClientMessage" event rather than doing a "KillClient()". The "ClientMessage" event allows a
program to clean-up or ask the user about saving a document before exiting, etc.

WM_STATE
The window manager maintains a state for each client window it manages,

WithdrawnState
NormalState
IconicState

Withdrawn means the window is not mapped and the window manager is not managing it. A Newly created
window ("$X->CreateWindow()") is initially withdrawn state and on first "$X->MapWindow()" goes to normal
state (or to iconic state if that's the initial state asked for in "WM_HINTS").

"iconify()" and "withdraw()" below can change the state to iconic or withdrawn. A window can be restored
from iconic to normal state by a "MapWindow()".

"($state, $icon_window) = X11::Protocol::WM::get_wm_state ($X, $window)"
Return the "WM_STATE" property from $window. This is set by the window manager on top-level
application windows. If there's no such property then the return is an empty list.

$state returned is an enum string, or an integer value if "$X->{'do_interp'}" is disabled or the
value unrecognised.

"WithdrawnState" 0 not displayed
"NormalState" 1 window displayed
"IconicState" 3 iconified in some way

"ZoomState" 2 \ no longer in ICCCM
"InactiveState" 4 / (zoom meant maximized)

$icon_window returned is the window (integer XID) used by the window manager to display an icon of
$window. If there's no such window then $icon_window is "None" (or 0 if "$X->{'do_interp'}" is
disabled).

$icon_window might be the icon window from the client's "WM_HINTS" or it might be a window created by
the window manager. The client can draw into it for animations etc, perhaps selecting "Expose"
events on it to know when to redraw.

"WM_STATE" is set by the window manager when a toplevel window is first mapped (or perhaps earlier),
and then kept up-to-date. Generally no "WM_STATE" property or a "WM_STATE" set to WithdrawnState
means the window manager is not managing the window, or not yet doing so. A client can select
"PropertyChange" event mask in the usual way to listen for "WM_STATE" changes.

"($state, $icon_window) = X11::Protocol::WM::unpack_wm_state ($X, $bytes)"
Unpack the bytes of a "WM_STATE" property to a $state and $icon_window as per "get_wm_state()" above.

$X is used for "$X->{'do_interp'}" but there's no communication with the server.

"X11::Protocol::WM::iconify ($X, $window)"
"X11::Protocol::WM::iconify ($X, $window, $root)"
Change $window to "IconicState" by sending a "ClientMessage" to the window manager. If there's no
window manager running then iconification is not possible and this message does nothing.

$root should be the root window of $window. If not given or "undef" then it's obtained from a
"QueryTree()". Any client can iconify any top level window.

If $window has other windows which are "WM_TRANSIENT_FOR" for it then generally the window manager
will iconify or hide those windows too (see "WM_TRANSIENT_FOR" below).

"X11::Protocol::WM::withdraw ($X, $window)"
"X11::Protocol::WM::withdraw ($X, $window, $root)"
Change $window to "WithdrawnState" by an "$X->UnmapWindow()" and a synthetic "UnmapNotify" message to
the window manager.

If there's no window manager running then the "UnmapWindow()" unmaps and the "UnmapNotify" message
does nothing.

$root should be the root window of $window. If not given or "undef" then it's obtained from a
"$X->QueryTree()".

If other windows are "WM_TRANSIENT_FOR" this $window (eg. open dialog windows) then generally the
client should withdraw them too. The window manager might make such other windows inaccessible
anyway.

The ICCCM specifies an "UnmapNotify" message so the window manager is notified of the desired state
change even if $window is already unmapped, such as in "IconicState" or perhaps during some window
manager reparenting, etc.

$window can be changed back to NormalState or IconicState later with "$X->MapWindow()" the same as
for a newly created window. (And "WM_HINTS" "initial_state" can give a desired initial iconic/normal
state). But before doing so be sure the window manager has recognised the "withdraw()". This will
be when the window manager changes the "WM_STATE" property to "WithdrawnState", or deletes that
property.

Any client can withdraw any toplevel window, but it's unusual for a client to withdraw windows which
are not its own.

WM_TRANSIENT_FOR
"X11::Protocol::WM::set_wm_transient_for ($X, $window, $transient_for)"
Set the "WM_TRANSIENT_FOR" property on $window (an XID).

$transient_for is another window XID, or "undef" if $window is not transient for anything so
"WM_TRANSIENT_FOR" should be deleted.

"Transient for" means $window is some sort of dialog or menu related to the given $transient_for
window. The window manager will generally iconify $window together with its $transient_for, etc.
See "set_motif_wm_hints()" below for "modal" transients.

_MOTIF_WM_HINTS
"X11::Protocol::WM::set_motif_wm_hints ($X, $window, key=>value...)"
Set the "MOTIF_WM_HINTS" property on $window (an XID).

These hints control window decorations and "modal" state. It originated in the Motif "mwm" window
manager but is recognised by most other window managers. It should be set on a toplevel window
before mapping. Changes made later might not affect what the window manager does.

X11::Protocol::WM::set_motif_wm_hints
($X, $dialog_window,
input_mode => "full_application_modal");
$X->MapWindow ($dialog_window);

Ordinary windows generally don't need to restrict their decorations etc, but something special like a
clock or gadget might benefit.

X11::Protocol::WM::set_motif_wm_hints
($X, $my_gadget_window,
functions => 4+32, # move+close
decorations => 1+4+8); # border+title+menu

The key/value arguments are

functions => integer bits
decorations => integer bits
input_mode => enum string or integer
status => integer bits

"functions" is what actions the window manager should offer to the user in a drop-down menu or
similar. It's an integer bitwise OR of the following values. If not given then the default is
normally all functions.

bit actions offered
--- ---------------
1 all functions
2 resize window
4 move window
8 minimize, to iconify
16 maximize, to full-screen (with a frame still)
32 close window

"decorations" is what visual decorations the window manager should show around the window. It's an
integer bitwise OR of the following values. If not given then the default is normally all
decorations.

bit decorations displayed
--- ---------------------
1 all decorations
2 border around the window
4 resizeh, handles to resize by dragging
8 title bar, showing WM_NAME
16 menu, drop-down menu of the "functions" above
32 minimize button, to iconify
64 maximize button, to full-screen

"input_mode" allows a window to be "modal", meaning the user should interact only with $window. The
window manager will generally keep it on top, not move the focus to other windows, etc. The value is
one of the following strings or corresponding integer,

string integer
"modeless" 0 not modal (the default)
"primary_application_modal" 1 modal to its "transient for"
"system_modal" 2 modal to the whole display
"full_application_modal" 3 modal to the current client

"primary_application_modal" means $window is modal for the "WM_TRANSIENT_FOR" set on $window (see
"WM_TRANSIENT_FOR" above), but other windows on the display can be used normally.
"full_application_modal" means modal for all windows of the same client, but other clients can be
used normally.

Modal behaviour is important for good user interaction and therefore ought to be implemented by a
window manager, but a good program should be prepared to do something with input on other windows.

"status" field is a bitwise OR of the following bits (only one currently).

bit
1 tearoff menu window

Tearoff menu flag is intended for tearoff menus, as the name suggests.

X11::Protocol::WM::set_motif_wm_hints
($X, $my_tearoff_window, status => 1);

Motif "mwm" will expand the window to make it wide enough for the "WM_NAME" in the frame title bar.
Otherwise a title is generally truncated to as much as fits the window's current width. Expanding
can be good for tearoffs where the title bar is some originating item name etc which the user should
see. But don't be surprised if this flag is ignored by other window managers.

Perhaps in the future the individual bits above will have some symbolic names. Either constants or
string values interpreted. What would a possible "get_hints()" return, and what might be convenient
to add/subtract bits?

See /usr/include/Xm/MwmUtil.h on the hints bits, and see "mwm" sources WmWinInfo.c
"ProcessWmWindowTitle()" for the "status" tearoff window flag.

_NET_FRAME_EXTENTS
"my ($left,$right, $top,$bottom) = X11::Protocol::WM::get_net_frame_extents ($X, $window)"
Get the "_NET_FRAME_EXTENTS" property from $window.

This is set on top-level windows by the window manager to report how many pixels of frame or
decoration it has added around $window.

If there's no such property set then the return is an empty list. So for example

my ($left,$right,$top,$bottom)
= get_net_frame_extents ($X, $window)
or print "no frame extents";

my ($left,$right,$top,$bottom)
= get_net_frame_extents ($X, $window);
if (! defined $left) {
print "no frame extents";
}

A client might look at the frame size if moving a window programmatically so as not to put the title
bar etc off-screen. Oldish window managers might not provide this information though.

_NET_WM_PID
"X11::Protocol::WM::set_net_wm_pid ($X, $window)"
"X11::Protocol::WM::set_net_wm_pid ($X, $window, $pid)"
"X11::Protocol::WM::set_net_wm_pid ($X, $window, undef)"
Set the "_NET_WM_PID" property on $window to the given $pid process ID, or to the $$ current process
ID if omitted. (See perlvar for $$.) If $pid is "undef" then the property is deleted.

A window manager or similar might use the PID to forcibly kill an unresponsive client. It's only
useful if "WM_CLIENT_MACHINE" (above) is set too, to know where the client is running.

_NET_WM_STATE
An EWMH compliant window manager maintains a set of state flags for each client window. A state is an
atom such as "_NET_WM_STATE_FULLSCREEN" and each such state can be present or absent. The supported
states are listed in "_NET_SUPPORTED". Any client can ask the window manager to change states on any
window. A client might be able to ask for an initial set of states for a new window (see
"set_net_wm_state()" below). Possible states include

_NET_WM_STATE_MODAL
The window is modal to its "WM_TRANSIENT_FOR" parent or if "WM_TRANSIENT_FOR" not set then modal to
its window group.

See "_MOTIF_WM_HINTS" to set modal with the Motif style hints.

_NET_WM_STATE_STICKY
The window is kept in a fixed position on screen when the desktop scrolls.

_NET_WM_STATE_MAXIMIZED_VERT
_NET_WM_STATE_MAXIMIZED_HORZ
The window is maximum size vertically or horizontally or both. The window still has its surrounding
decoration and the size should obey size increments specified in "WM_NORMAL_HINTS".

_NET_WM_STATE_FULLSCREEN
The window is the full screen with no decoration around it, thus being the full screen.

The window manager remembers the "normal" size of the window so that when maximize or fullscreen
state is removed the previous size is restored.

_NET_WM_STATE_SHADED
The window is "shaded" which generally means its title bar is displayed but none of the client
window. This is an alternative to iconifying a window.

_NET_WM_STATE_SKIP_TASKBAR
_NET_WM_STATE_SKIP_PAGER
Don't show the window on a task bar or in a pager, respectively.

_NET_WM_STATE_HIDDEN (read-only)
This state is set by the window manger when the window is iconified or similar and so does not appear
on screen. Clients cannot change this.

_NET_WM_STATE_ABOVE
_NET_WM_STATE_BELOW
The window is kept above or below other client windows. The stacking order maintained is roughly

_NET_WM_STATE_DEMANDS_ATTENTION
The window should be brought to the attention of the user in some way. A client sets this and the
window manager clears it after the window has received user attention (which might mean keyboard
focus or similar).

The following functions get or set the states.

"change_net_wm_state($X, $window, $action, $state, key=>value,...)"
Change one of the "_NET_WM_STATE" state flags on $window by sending a message to the window manager.
For example,

change_net_wm_state ($X, $window, "toggle", "FULLSCREEN");

$window must be a managed window, ie. must have had its initial "MapWindow()" and not be an override-
redirect. If that's not so or if there's no window manager or it doesn't have EWMH then this change
message will have no effect.

$action is a string or integer how to change the state,

"remove" 0
"add" 1
"toggle" 2

$state is a string such as "FULLSCREEN" or an atom integer such as
"$X->atom("_NET_WM_STATE_FULLSCREEN")".

The further optional key/value parameters are

state2 => string or atom
source => "none", "normal", "user", 0,1,2
root => integer XID, or undef

A change message can act on one or two states. For two states the second is "state2". For example
to maximize vertically and horizontally in one operation,

change_net_wm_state ($X, $window, "add", "MAXIMIZED_VERT",
state2 => "MAXIMIZED_HORZ");

"source" is where the change request came from. The default is "normal" which means a normal
application. "user" is for a user-interface control program such as a pager. ("none"=0 is what
clients prior to EWMH 1.2 gave.)

"root" is the root window (integer XID) of $window. If "undef" or not given then it's found with
"$X->QueryTree()". If you already know the root then giving it avoids that round-trip query.

"@strings = get_net_wm_state ($X, $window)"
"@atoms = get_net_wm_state_atoms ($X, $window)"
Get the "_NET_WM_STATE" property from $window. "get_net_wm_state()" returns a list of strings such
as "FULLSCREEN". "get_net_wm_state_atoms()" returns a list of atom integers such as
"$X->atom('_NET_WM_STATE_FULLSCREEN')". In both cases if there's no such property or if it's empty
then return an empty list.

"set_net_wm_state ($X, $window, $state,...)"
Set the "_NET_WM_STATE" property on $window. Each $state can be a string such as "FULLSCREEN" or an
atom integer such as "$X->atom('_NET_WM_STATE_FULLSCREEN')".

A client can set "_NET_WM_STATE" on a new window to tell the window manager of desired initial
states. However this is only a "should" in the EWMH spec so it might not be obeyed.

# initial desired state
set_net_wm_state ($X, $window,
"MAXIMIZED_HORZ", "MAXIMIZED_VERT");

After the window is managed by the window manager (once mapped) clients should not set
"_NET_WM_STATE" but instead ask the window manager with "change_net_wm_state()" per above.

_NET_WM_USER_TIME
"set_net_wm_user_time ($X, $window, $time)"
Set the "_NET_WM_USER_TIME" property on $window.

$time should be a server time value (an integer) from the last user keypress etc event in $window.
Or when $window is created then the time from the event which caused it to be opened.

On a newly created window a special $time value 0 means the window should not receive the focus when
mapped -- assuming the window manager recognises "_NET_WM_USER_TIME" of course.

If the client has the active window it should update "_NET_WM_USER_TIME" for every user input.
Generally KeyPress and ButtonPress events are user input, but KeyRelease and ButtonRelease are not
since it's the Press events which are the user actively doing something.

The window manager might use "_NET_WM_USER_TIME" to control focus and/or stacking order so that for
example a slow popup doesn't steal the focus if you've gone to another window to do other work in the
interim.

_NET_WM_WINDOW_TYPE
"X11::Protocol::WM::set_net_wm_window_type ($X, $window, $window_type)"
Set the "_NET_WM_WINDOW_TYPE" property on $window (an XID). $window_type can be a type string as
follows from the EWMH,

"NORMAL"
"DIALOG"
"DESKTOP"
"DOCK"
"TOOLBAR"
"MENU"
"UTILITY"
"SPLASH"

$window_type can also be an integer atom such as "$X->atom('_NET_WM_WINDOW_TYPE_DIALOG')".

Frame to Client
"$window = X11::Protocol::WM::frame_window_to_client ($X, $frame)"
Return the client window (XID) contained within window manager $frame window (an XID). $frame is
usually an immediate child of the root window.

If no client window can be found in $frame then return "undef". This might happen if $frame is an
icon window or similar created by the window manager itself, or an override-redirect client without a
frame, or if there's no window manager running at all. In the latter two cases $frame would be the
client already.

The strategy is to look at $frame and down the window tree seeking a "WM_STATE" property which the
window manager puts on a client's toplevel when mapped. The search depth and total windows are
limited in case the window manager does its decoration in some ridiculous way or the client uses
excessive windows (which would be traversed if there's no window manager).

+-rootwin--------------------------+
| |
| |
| +-frame-win--------+ |
| | +-client-win---+ | |
| | | WM_STATE ... | | |
| | | | | |
| | +--------------+ | |
| +------------------+ |
| |
+----------------------------------+

Care is taken not to error out if some windows are destroyed during the search. The windows may
belong to other clients and could be destroyed at any time. If $frame itself doesn't exist then the
return is "undef".

This function is similar to what "xwininfo" and similar programs do to go from a toplevel root window
child down to the client window, per dmsimple.c "Select_Window()" or Xlib "XmuClientWindow()". (See
also X11::Protocol::ChooseWindow.)

Virtual Root
Some window managers use a "virtual root" window covering the entire screen. Application windows or
frame windows are then children of that virtual root. This can help the window manager implement a large
desktop or multiple desktops, though it tends to fail in subtle ways with various root oriented programs,
including for example xsetroot(1) or the click-to-select in xwininfo(1) and xprop(1).

"$window = X11::Protocol::WM::root_to_virtual_root ($X, $root)"
If the window manager is using a virtual root then return that window XID. If not then return
"undef".

The current implementation searches for a window with an "__SWM_VROOT" property, as per the "swm",
"tvtwm" and "amiwm" window managers, and as used by the "xscreensaver" program and perhaps some
versions of KDE.

There's nothing yet for EWMH "_NET_VIRTUAL_ROOTS". Do any window managers use it? Is
"_NET_CURRENT_DESKTOP" an index into that virtual roots list?

(See X11::Protocol::XSetRoot for changing the background of a root or virtual root.)

EXPORTS

       Nothing is exported by default, but the functions can be requested in usual "Exporter" style,

           use X11::Protocol::WM 'set_wm_hints';
           set_wm_hints ($X, $window, input => 1, ...);

       Or just call with full package name

           use X11::Protocol::WM;
           X11::Protocol::WM::set_wm_hints ($X, $window, input => 1, ...);

       There's no ":all" tag since this module is meant as a grab-bag of functions and to import as-yet  unknown
       things would be asking for name clashes.

BUGS

       Not  much  attention  is  paid  to  text  on an EBCDIC system.  Wide char strings probably work, but byte
       strings may go straight through where they ought to be  re-coded  to  Latin-1.   But  the  same  probably
       applies  to  parts  of  the  core  "X11::Protocol"  such as "$X->atom_name()" where you'd want to convert
       Latin-1 from the server to native EBCDIC.

HOME PAGE

       <http://user42.tuxfamily.org/x11-protocol-other/index.html>

LICENSE

       Copyright 2011, 2012, 2013 Kevin Ryde

       X11-Protocol-Other  is free software; you can redistribute it and/or modify it under the terms of the GNU
       General Public License as published by the Free Software  Foundation;  either  version  3,  or  (at  your
       option) any later version.

       X11-Protocol-Other  is  distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
       even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See  the  GNU  General
       Public License for more details.

       You should have received a copy of the GNU General Public License along with X11-Protocol-Other.  If not,
       see <http://www.gnu.org/licenses/>.

perl v5.18.2                                       2013-11-04                             X11::Protocol::WM(3pm)