kwin/wm-spec/x107.html
Luboš Luňák f52b8e48cd branches/work/kwin_composite becomes new trunk kwin.
svn path=/trunk/KDE/kdebase/workspace/; revision=659202
2007-04-29 17:35:43 +00:00

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>Root Window Properties (+Related Messages)</TITLE
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><H1
CLASS="SECT1"
><A
NAME="AEN107"
>3. Root Window Properties (+Related Messages)</A
></H1
><P
>Whenever this spec speaks about <SPAN
CLASS="QUOTE"
>"sending a message to the root
window"</SPAN
>, it is understood that the client is supposed to create
a ClientMessage event with the specified contents and send it by using
a SendEvent request with the following arguments:
<PRE
CLASS="PROGRAMLISTING"
>destination root
propagate False
event-mask (SubstructureNotify|SubstructureRedirect)
event the specified ClientMessage</PRE
>
</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN112"
>3.1. _NET_SUPPORTED</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_SUPPORTED, ATOM[]/32</PRE
><P
>This property MUST be set by the Window Manager to indicate which hints it
supports. For example: considering _NET_WM_STATE
both this atom and all supported states e.g. _NET_WM_STATE_MODAL,
_NET_WM_STATE_STICKY, would be listed. This assumes that backwards
incompatible changes will not be made to the hints (without being renamed).
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN116"
>3.2. _NET_CLIENT_LIST</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_CLIENT_LIST, WINDOW[]/32
_NET_CLIENT_LIST_STACKING, WINDOW[]/32</PRE
><P
>These arrays contain all X Windows managed by the Window Manager.
_NET_CLIENT_LIST has initial mapping order, starting with the oldest window.
_NET_CLIENT_LIST_STACKING has bottom-to-top stacking order. These properties
SHOULD be set and updated by the Window Manager.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN120"
>3.3. _NET_NUMBER_OF_DESKTOPS</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_NUMBER_OF_DESKTOPS, CARDINAL/32</PRE
><P
>This property SHOULD be set and updated by the Window Manager to indicate the
number of virtual desktops.
</P
><P
>A Pager can request change in the desktops number by sending a _NET_NUMBER_OF_DESKTOPS message to the root window:
</P
><PRE
CLASS="PROGRAMLISTING"
>_NET_NUMBER_OF_DESKTOPS
message_type = _NET_NUMBER_OF_DESKTOPS
format = 32
data.l[0] = new_number_of_desktops</PRE
><P
>The Window Manager is free to honor or reject this request. If request is honored _NET_NUMBER_OF_DESKTOPS MUST be set to the new number of desktops, _NET_VIRTUAL_ROOTS MUST be set to store the new number of desktop virtual root window IDs and _NET_DESKTOP_VIEWPORT and _NET_WORKAREA must also be changed accordingly. The _NET_DESKTOP_NAMES property MAY remain unchanged.
</P
><P
>
If the number of desktops is shrinking and _NET_CURRENT_DESKTOP is out of the new range of available desktops, then this MUST be set to the last available desktop from the new set. If number of desktops is shrinking then clients that are still present on desktops, that are out of the new range, MUST be moved to the very last desktop from the new set. For these _NET_WM_DESKTOP MUST be updated.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN128"
>3.4. _NET_DESKTOP_GEOMETRY</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_DESKTOP_GEOMETRY width, height, CARDINAL[2]/32</PRE
><P
>Array of two cardinals that defines the common size of all desktops.
This property SHOULD be set by the Window Manager.
</P
><P
>A Pager can request a change in the desktop geometry by sending a _NET_DESKTOP_GEOMETRY client
message to the root window:
</P
><PRE
CLASS="PROGRAMLISTING"
>_NET_DESKTOP_GEOMETRY
message_type = _NET_DESKTOP_GEOMETRY
format = 32
data.l[0] = new_width
data.l[1] = new_height</PRE
><P
>The Window Manager MAY choose to ignore this message, in which case _NET_DESKTOP_GEOMETRY property will remain unchanged.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN135"
>3.5. _NET_DESKTOP_VIEWPORT</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_DESKTOP_VIEWPORT x, y, CARDINAL[][2]/32</PRE
><P
>Array of pairs of cardinals that define the top left corner of each desktops
viewport. For Window Managers that don't support large desktops, this MUST
always be set to (0,0).
</P
><P
>A Pager can request to change the viewport for the current desktop by sending a
_NET_DESKTOP_VIEWPORT client message to the root window:
</P
><PRE
CLASS="PROGRAMLISTING"
>_NET_DESKTOP_VIEWPORT
message_type = _NET_DESKTOP_VIEWPORT
format = 32
data.l[0] = new_vx
data.l[1] = new_vy</PRE
><P
>The Window Manager MAY choose to ignore this message, in which case _NET_DESKTOP_VIEWPORT property will remain unchanged.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN142"
>3.6. _NET_CURRENT_DESKTOP</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_CURRENT_DESKTOP desktop, CARDINAL/32</PRE
><P
>The index of the current desktop. This is always an integer between 0 and
_NET_NUMBER_OF_DESKTOPS - 1. This MUST be set and updated by the Window
Manager If a Pager wants to switch to another virtual desktop, it MUST send
a _NET_CURRENT_DESKTOP client message to the root window:
</P
><PRE
CLASS="PROGRAMLISTING"
>_NET_CURRENT_DESKTOP
message_type = _NET_CURRENT_DESKTOP
format = 32
data.l[0] = new_index</PRE
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN147"
>3.7. _NET_DESKTOP_NAMES</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_DESKTOP_NAMES, UTF8_STRING[]</PRE
><P
>The names of all virtual desktops. This is a list of NULL-terminated strings in UTF-8 [1] encoding. This property MAY be changed by a Pager or the Window Manager at any time.
</P
><P
>Note: The number of names could be different from _NET_NUMBER_OF_DESKTOPS.
If it is less than _NET_NUMBER_OF_DESKTOPS - then the desktops with high
numbers are unnamed. If it is larger than _NET_NUMBER_OF_DESKTOPS, then the
excess names outside of the _NET_NUMBER_OF_DESKTOPS are considered to be
reserved in case number of desktops is increased.</P
><P
>Rationale: The name is not a necessary attribute of a virtual desktop. Thus
the availability or unavailability of names has no impact on virtual desktop
functionality. Since names are set by users and users are likely to preset
names for a fixed number of desktops, it doesn't make sense to shrink or grow
this list when the number of available desktops changes.</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN153"
>3.8. _NET_ACTIVE_WINDOW</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_ACTIVE_WINDOW, WINDOW/32</PRE
><P
>The window ID of the currently active window or None if no window has the focus.
This is a read-only property set by the
Window Manager. If a client (for example, a taskbar) wants to activate
another window, it MUST send a _NET_ACTIVE_WINDOW client message to the root
window:
</P
><PRE
CLASS="PROGRAMLISTING"
>_NET_ACTIVE_WINDOW
window = window to activate
message_type = _NET_ACTIVE_WINDOW
format = 32
data.l[0] = 0 /* may be used later */</PRE
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN158"
>3.9. _NET_WORKAREA</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_WORKAREA, x, y, width, height CARDINAL[][4]/32
</PRE
><P
>This property MUST be set by WM upon calculating the work area for
each desktop. Contains a geometry for each desktop. These geometries are
specified relative to the viewport on each desktop and specify an area that is
completely contained within the viewport.
Work area SHOULD be used by desktop applications to place desktop icons appropriately.
</P
><P
> The Window Manager SHOULD calculate this space by taking the current page minus space occupied by dock and panel windows, as indicated by the <A
HREF="x225.html#NETWMSTRUT"
>_NET_WM_STRUT</A
> property set on client windows.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN164"
>3.10. _NET_SUPPORTING_WM_CHECK</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_SUPPORTING_WM_CHECK, WINDOW/32</PRE
><P
>The Window Manager MUST set this property on the root window to be the ID of a
child window created by the WM, to indicate that a compliant WM is
active. The child window MUST also have the _NET_SUPPORTING_WM_CHECK
property set to the ID of the child window. The child window MUST also
have the _NET_WM_NAME property set to the name of the Window Manager.
</P
><P
>Rationale: The child window is used to distinguish an active Window Manager
from a stale _NET_SUPPORTING_WM_CHECK
property that happens to point to another window. If the
_NET_SUPPORTING_WM_CHECK window on the client window is missing
or not properly set, clients SHOULD assume that no conforming
Window Manager is present.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN169"
>3.11. _NET_VIRTUAL_ROOTS</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_VIRTUAL_ROOTS, WINDOW[]/32</PRE
><P
>To implement virtual desktops, some window managers reparent client windows to
a child of the root window. Window managers using this technique MUST set
this property to a list of IDs for windows that are acting as virtual root
windows. This property allows background setting programs to work with
virtual roots and allows clients to figure out the WM frame windows of their
windows.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN173"
>3.12. _NET_DESKTOP_LAYOUT</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_DESKTOP_LAYOUT, orientation, x, y, starting_corner CARDINAL[4]/32
#define _NET_WM_ORIENTATION_HORZ 0
#define _NET_WM_ORIENTATION_VERT 1
#define _NET_WM_TOPLEFT 0
#define _NET_WM_TOPRIGHT 1
#define _NET_WM_BOTTOMRIGHT 2
#define _NET_WM_BOTTOMLEFT 3</PRE
><P
> <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>This property is set by a Pager, not by the Window
Manager.</I
></SPAN
>
When setting this property, the Pager must own a manager selection (as
defined in the ICCCM 2.8). The manager selection is called
<TT
CLASS="LITERAL"
>_NET_DESKTOP_LAYOUT_Sn</TT
> where
<TT
CLASS="LITERAL"
>n</TT
> is the screen number. The purpose of
this property is to allow the Window Manager to know the desktop
layout displayed by the Pager.
</P
><P
> <TT
CLASS="LITERAL"
>_NET_DESKTOP_LAYOUT</TT
> describes the layout of virtual
desktops relative to each other. More specifically, it describes the layout
used by the owner of the manager selection. The Window Manager may use
this layout information or may choose to ignore it.
The property contains four values: the Pager orientation, the number of
desktops in the X direction, the number in the Y direction, and the
starting corner of the Pager.
</P
><P
> Note: In order to interoperate with Pagers implementing an earlier
draft of this document, Window Managers should accept a
<TT
CLASS="LITERAL"
>_NET_DESKTOP_LAYOUT</TT
> property of length 3 and
use <TT
CLASS="LITERAL"
>_NET_WM_TOPLEFT</TT
> as the starting corner in this case.
</P
><P
> The virtual desktops are arranged in a rectangle
with X rows and Y columns. If X times Y does not match the total number of
desktops as specified by
<TT
CLASS="LITERAL"
>_NET_NUMBER_OF_DESKTOPS</TT
>, the highest-numbered
workspaces are assumed to be nonexistent. Either X or Y (but not
both) may be specified as 0 in which case its actual value will be
derived from <TT
CLASS="LITERAL"
>_NET_NUMBER_OF_DESKTOPS</TT
>.
</P
><P
> When the orientation is <TT
CLASS="LITERAL"
>_NET_WM_ORIENTATION_HORZ</TT
>
the desktops are layed out in rows, with the first desktop in the
specified starting corner. So a layout with X=4 and Y=3 starting in
the <TT
CLASS="LITERAL"
>_NET_WM_TOPLEFT</TT
> corner looks like this:
<PRE
CLASS="PROGRAMLISTING"
> +--+--+--+--+
| 0| 1| 2| 3|
+--+--+--+--+
| 4| 5| 6| 7|
+--+--+--+--+
| 8| 9|10|11|
+--+--+--+--+</PRE
>
With starting_corner <TT
CLASS="LITERAL"
>_NET_WM_BOTTOMRIGHT</TT
>, it looks like
this:
<PRE
CLASS="PROGRAMLISTING"
> +--+--+--+--+
|11|10| 9| 8|
+--+--+--+--+
| 7| 6| 5| 4|
+--+--+--+--+
| 3| 2| 1| 0|
+--+--+--+--+</PRE
>
</P
><P
>&#13; When the orientation is <TT
CLASS="LITERAL"
>_NET_WM_ORIENTATION_VERT</TT
>
the layout for X=4 and Y=3 starting in the <TT
CLASS="LITERAL"
>_NET_WM_TOPLEFT</TT
>
corner looks like:
<PRE
CLASS="PROGRAMLISTING"
> +--+--+--+--+
| 0| 3| 6| 9|
+--+--+--+--+
| 1| 4| 7|10|
+--+--+--+--+
| 2| 5| 8|11|
+--+--+--+--+</PRE
>
With starting_corner <TT
CLASS="LITERAL"
>_NET_WM_TOPRIGHT</TT
>, it looks like:
<PRE
CLASS="PROGRAMLISTING"
> +--+--+--+--+
| 9| 6| 3| 0|
+--+--+--+--+
|10| 7| 4| 1|
+--+--+--+--+
|11| 8| 5| 2|
+--+--+--+--+</PRE
>
</P
><P
> The numbers here are the desktop numbers, as for
<TT
CLASS="LITERAL"
>_NET_CURRENT_DESKTOP</TT
>.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN202"
>3.13. _NET_SHOWING_DESKTOP</A
></H2
><PRE
CLASS="PROGRAMLISTING"
>_NET_SHOWING_DESKTOP desktop, CARDINAL/32</PRE
><P
> Some Window Managers have a "showing the desktop" mode in which windows
are hidden, and the desktop background is displayed and focused. If a
Window Manager supports the _NET_SHOWING_DESKTOP hint, it MUST set it
to a value of 1 if the Window Manager is in "showing the desktop" mode,
and a value of zero if the Window Manager is not in this mode.
</P
><P
> If a Pager wants to enter or leave the mode, it MUST
send a _NET_SHOWING_DESKTOP client message to the root window
requesting the change:
<PRE
CLASS="PROGRAMLISTING"
>_NET_SHOWING_DESKTOP
message_type = _NET_SHOWING_DESKTOP
format = 32
data.l[0] = boolean 0 or 1</PRE
>
The Window Manager may choose to ignore this client message.
</P
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