Re: Window History Placement
- From: Matthias Clasen <maclas gmx de>
- To: wm-spec-list gnome org
- Subject: Re: Window History Placement
- Date: 30 Jan 2003 00:20:34 +0100
On Wed, 2003-01-29 at 16:09, Havoc Pennington wrote:
> _NET_WM_SAVE_ID lets apps:
> - explicitly control placement history, which may be pretty different
> than SM; for example a valid way to handle SM is to just close all
> dialogs on session save, rather than setting the role on them
> - lets them disable placement history
> - lets them detect whether the WM supports placement history
> by checking for support of _NET_WM_SAVE_ID
Nice summary. Why would a Client want to know about history placement
support though ?
Here is a new patch, incorporating some of the comments.
RCS file: /home/freedesktop/wm-spec/wm-spec.sgml,v
retrieving revision 1.28
diff -u -b -B -p -r1.28 wm-spec.sgml
--- wm-spec.sgml 3 Jan 2003 20:29:28 -0000 1.28
+++ wm-spec.sgml 29 Jan 2003 21:54:59 -0000
@@ -234,6 +234,23 @@ layer.
+Placement of newly-mapped windows is an area where Window Managers
+have traditionally offered a wide range of policies. Simple policies
+like always using the provided geometry or interactive placement are
+already (partially) covered by the ICCCM. Beyond this most Window
+Managers offer automatic policies like tiling, stacking or various
+More recently, "history placement", i.e. restoring the window to it's last
+known position has been introduced. Unlike most other placement policies,
+history placement needs a bit of cooperation from the Client to identify
+which windows are to be considered `the same'.
<title>Scope of this spec</title>
<para>This spec tries to address the following issues:</para>
@@ -244,6 +261,7 @@ decorations and maintain the stacking or
window manager about the type of their windows.</para></listitem>
<listitem><para>Enable pagers and taskbars to be implemented as separate
clients and allow them to work with any compliant window manager.</para></listitem>
+<listitem><para>Support history placement.</para></listitem>
<para>This spec doesn't cover any of the following:</para>
@@ -1205,6 +1223,20 @@ _NET_WM_HANDLED_ICONS
for iconified windows.
+ If this property is set to a non-empty string, the Window Manager
+ will use it to identify this window for the purpose of
+ <link linkend="HISTORY">history placement</link>. If it is not set,
+ the Window Manager may identify the window by other means (see
+ <xref linkend="PLACEMENT">).
+ If it is set to the empty string, the Window Manager should not store
+ the location of this window for history placement.
<title>Window Manager Protocols</title>
@@ -1613,6 +1645,35 @@ int net_get_hostname (char *buf, size_t
+ <sect2 id="PLACEMENT">
+ <title>Placement policies</title>
+ Clients should specify USPosition in the WM_NORMAL_HINTS property to
+ indicate the initial geometry has been explicitly requested by the
+ user (typically via a --geometry command line option).
+ Placement policies should not be applied if the geometry is restored
+ from a saved session. Many Clients erroneously rely on their initial
+ geometry being granted if USPosition or PPosition is specified in the
+ WM_NORMAL_HINTS property, thus Window Managers are well advised to
+ honour these flags at least optionally.
+ To identify a window without _NET_WM_SAVE_ID for the purpose of
+ history placement, the Window Manager may use a combination of
+ WM_CLASS, WM_NAME, SM_CLIENT_ID and WM_WINDOW_ROLE plus an
+ additional tag to differentiate between windows which would otherwise
+ be considered identical. One possibility to generate the tag is to
+ count the windows with the same combination.
+ Note that restoring a window's size (from history or a saved session)
+ requires to also restore its maximization and fullscreen state —
+ otherwise maximized windows will be restored to screen-size normal
@@ -1715,6 +1776,10 @@ and renamed them to columns and row for
Change the description of _NET_WM_STATE_MODAL to no longer require apps to
break the ICCCM for group-modal windows, but still support the
+Added _NET_WM_SAVE_ID to support history placement, together with an
+introductory section and implemenation notes on placement policies.
] [Thread Prev