/ 
X11-Protocol-Other-21
/ X11::Protocol::WM

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"

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

Usual Properties

Any client window should generally

Then optionally,

  • If the client has an icon then set_wm_hints() with that (pixmap or window).

  • 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 to declare.

  • 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 which open file etc.

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. 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, with manipulations for such content etc. If text is bytes in one of the ICCCM encodings then it may 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, but 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 names so the user can have different window manager settings applied to a particular running client.

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

icon_window is a window which the window manager can 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 its 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 create a window which is never mapped but just acts as the leader for 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. 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 avoid a round-trip by remembering its desired hints and sending changes with 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. Newly created windows start as withdrawn and on their first MapWindow() go 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 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      neither window nor icon display
"NormalState"       1      window displayed
"IconicState"       3      iconified in some way

"ZoomState"         2      \ no longer in ICCCM
"InactiveState"     4      /

$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 created by the window manager. Either way 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 mean 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 the 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 any windows which are "transient" for it (see "WM_TRANSIENT_FOR" below) then usually the window manager will iconify or hide those windows too.

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 $window is unmapped 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 QueryTree().

If any windows are WM_TRANSIENT_FOR this $window then generally the client should withdraw them too. The window manager might make such transients 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 when it's in IconicState or perhaps during some window manager reparenting, etc.

$window can be changed back to NormalState or IconicState later with a $X->MapWindow() the same as for a newly created window (with WM_HINTS initial_state for desired initial state). But before doing so be sure the window manager has recognised the withdraw(), by it changing WM_STATE to WithdrawnState.

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. 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).

This controls window decorations and "modal" state. It originated in the Motif mwm window manager but is recognised by many 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_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 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 managerM implement a large desktop, or multiple desktops, though it tends to fail in subtle ways with various root oriented programs, including for example xsetroot or the xwininfo and xprop click-to-select.

$window = X11::Protocol::WM::root_to_virtual_root ($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 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.

SEE ALSO

X11::Protocol, X11::Protocol::Other, X11::Protocol::ChooseWindow, X11::Protocol::XSetRoot

"Inter-Client Communication Conventions Manual"

http://www.x.org/docs/ICCCM/
/usr/share/doc/xorg-docs/specs/ICCCM/icccm.txt.gz

"Compound Text Encoding" specification.

http://www.x.org/docs/CTEXT/
/usr/share/doc/xorg-docs/specs/CTEXT/ctext.txt.gz

"Extended Window Manager Hints" which is the _NET_WM things.

http://www.freedesktop.org/wiki/Specifications/wm-spec
http://mail.gnome.org/archives/wm-spec-list/

wmctrl(1), xwit(1), X(7)

HOME PAGE

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

LICENSE

Copyright 2011, 2012 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/>.