TDE base libraries and programs
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Slávek Banko b95b665c78
Add CMakeL10n rules.
5 months ago
..
clients Add CMakeL10n rules. Update TIMEZONES list. 5 months ago
compton-tde Avoid using 10bit FBConfigs 11 months ago
data Fix kdesktop_lock bad visual appearance due to incorrect focus stealing settings 4 years ago
kcmtwin Add CMakeL10n rules. Update TIMEZONES list. 5 months ago
killer LIB_QT -> LIB_TQT conversion to align to updated admin module 8 months ago
lib Add CMakeL10n rules. Update TIMEZONES list. 5 months ago
oldheaders Additional renaming of kde to tde 7 years ago
pics Fix invalid headers in PNG files and optimize for size 2 years ago
resumer Rename additional header files to avoid conflicts with KDE4 6 years ago
tools LIB_QT -> LIB_TQT conversion to align to updated admin module 8 months ago
wm-spec Remove additional unneeded tq method conversions 7 years ago
CMakeL10n.txt Add CMakeL10n rules. Update TIMEZONES list. 5 months ago
CMakeLists.txt Fix syntax errors in compton-tde configuration module Remove obsolete kompmgr 4 years ago
COMPLIANCE Add basic support for a modified compton compositor instead of the old buggy kompmgr Update additional Xorg atom names 5 years ago
CONFIGURING Rename a number of libraries and executables to avoid conflicts with KDE4 6 years ago
HACKING Update bug reports url to bugs.trinitydesktop.org 10 months ago
KWinInterface.h Add preliminary taskbar task state support 6 years ago
LICENSE Rename kwin to twin (Part 2 of 2) 7 years ago
Makefile.am Fix syntax errors in compton-tde configuration module Remove obsolete kompmgr 4 years ago
NEWCOLORSCHEME.README Rename kwin to twin (Part 2 of 2) 7 years ago
README Rename a number of libraries and executables to avoid conflicts with KDE4 6 years ago
activation.cpp Send setActive signal when taking focus in Client::takeFocus This relates to Bug 2189 Clean up minor formatting issues 4 years ago
atoms.cpp Add basic support for a modified compton compositor instead of the old buggy kompmgr Update additional Xorg atom names 5 years ago
atoms.h Rename kwin to twin (Part 2 of 2) 7 years ago
bridge.cpp Call setActive if new focus window is found and set when rotating focus to next available window This resolves Bug 2189 4 years ago
bridge.h Call setActive if new focus window is found and set when rotating focus to next available window This resolves Bug 2189 4 years ago
client.cpp Fix FTBFS with GCC7 1 year ago
client.h Send setActive signal when taking focus in Client::takeFocus This relates to Bug 2189 Clean up minor formatting issues 4 years ago
cr16-app-twin.png Fix invalid headers in PNG files and optimize for size 2 years ago
cr32-app-twin.png Fix invalid headers in PNG files and optimize for size 2 years ago
cr48-app-twin.png Fix invalid headers in PNG files and optimize for size 2 years ago
events.cpp Send setActive signal when taking focus in Client::takeFocus This relates to Bug 2189 Clean up minor formatting issues 4 years ago
eventsrc Fix kcontrol branding with event sound files. 7 years ago
geometry.cpp Fix remnant QMIN/QMAX to TQMIN/TQMAX. 5 years ago
geometrytip.cpp Fix remnant QMIN/QMAX to TQMIN/TQMAX. 5 years ago
geometrytip.h Rename kwin to twin (Part 2 of 2) 7 years ago
group.cpp Remove QT_CLEAN_NAMESPACE/TQT_CLEAN_NAMESPACE unnecessary define. 8 months ago
group.h Rename kwin to twin (Part 2 of 2) 7 years ago
killwindow.cpp Remove QT_CLEAN_NAMESPACE/TQT_CLEAN_NAMESPACE unnecessary define. 8 months ago
killwindow.h Rename kwin to twin (Part 2 of 2) 7 years ago
layers.cpp Rename additional global functions and variables for tqt3 7 years ago
main.cpp Remove QT_CLEAN_NAMESPACE/TQT_CLEAN_NAMESPACE unnecessary define. 8 months ago
main.h Rename common header files for consistency with class renaming 6 years ago
manage.cpp Rename additional header files to avoid conflicts with KDE4 6 years ago
notifications.cpp Rename a number of classes to enhance compatibility with KDE4 6 years ago
notifications.h Rename kwin to twin (Part 2 of 2) 7 years ago
options.cpp Rename KStyle to TDEStyle to avoid conflicts with KDE4. 5 years ago
options.h Revert "Rename a number of old tq methods that are no longer tq specific" 7 years ago
placement.cpp Send setActive signal when taking focus in Client::takeFocus This relates to Bug 2189 Clean up minor formatting issues 4 years ago
placement.h Rename kwin to twin (Part 2 of 2) 7 years ago
plugins.cpp Fix KWin->TWin references in text strings. 5 years ago
plugins.h Rename kwin to twin (Part 2 of 2) 7 years ago
popupinfo.cpp Remove QT_CLEAN_NAMESPACE/TQT_CLEAN_NAMESPACE unnecessary define. 8 months ago
popupinfo.h Rename kwin to twin (Part 2 of 2) 7 years ago
rules.cpp Fix remnant QMIN/QMAX to TQMIN/TQMAX. 5 years ago
rules.h Rename KCModule, KConfig, KIO, KServer, and KSocket to avoid conflicts with KDE4 6 years ago
sm.cpp Rename additional header files to avoid conflicts with KDE4 6 years ago
sm.h Rename common header files for consistency with class renaming 6 years ago
tabbox.cpp Remove QT_CLEAN_NAMESPACE/TQT_CLEAN_NAMESPACE unnecessary define. 8 months ago
tabbox.h Added Mac-like window switching for one app with keyboard shortcut Alt-~. This resolves bug report 869. Thanks to Calvin Morrison. 7 years ago
twin.kcfg Rename kwin to twin (Part 2 of 2) 7 years ago
twinbindings.cpp Rename KGlobal, KProcess, and KClipboard to avoid conflicts with KDE4 6 years ago
update_compton_tde Fix update_compton_tde script 4 years ago
useractions.cpp Fix exec icon location and bring it into XDG compliance 4 years ago
utils.cpp Fix FTBFS because missing header in twin utils 4 years ago
utils.h Rename many classes and header files to avoid conflicts with KDE4 6 years ago
workspace.cpp Remove QT_CLEAN_NAMESPACE/TQT_CLEAN_NAMESPACE unnecessary define. 8 months ago
workspace.h Rename many classes and header files to avoid conflicts with KDE4 6 years ago

README

- The mailing list for KWin is twin@kde.org (https://mail.kde.org/mailman/listinfo/twin).

- If you want to develop KWin, see file HACKING.

- If you want to check KWin's compliance with specifications, see file COMPLIANCE.

- File CONFIGURATION includes some details on configuring KWin.

- Below is some info for application developers about application interaction
with the window manager, but it'd need some cleanup.








This README is meant as an explanation of various window manager related
mechanisms that application developers need to be aware of. As some of these
concepts may be difficult to understand for people not having the required
background knowledge (since sometimes it's difficult even for people who
do have the knowledge), the mechanisms are first briefly explained, and
then an example of fixing the various problems is given.

For comments, questions, suggestions and whatever use the twin@kde.org
mailing list.


Table of contents:
==================

- Window relations
- how to make the window manager know which windows belong together
- Focus stealing prevention
- how to solve cases where focus stealing prevention doesn't work
properly automatically



Window relations:
=================

(For now, this explanation of window relations is mainly meant for
focus stealing prevention. To be extended later.)

All windows created by an application should be organized in a tree
with the root being the application's main window. Note that this is about
toplevel windows, not widgets inside the windows. For example, if you
have KWrite running, with a torn-off toolbar (i.e. a standalone toolbar),
a file save dialog open, and the file save dialog showing a dialog
for creating a directory, the window hiearchy should look like this:


KWrite mainwindow
/ \
/ \
file save dialog torn-off toolbar
\
\
create directory dialog

Each subwindow (i.e. all except for the KWrite mainwindow) points to its
main window (which in turn may have another main window, as in the case
of the file save dialog). When the window manager knows these relations,
it can better arrange the windows (keeping subwindows above their
main windows, preventing activation of a main window of a modal dialog,
and similar). Failing to provide this information to the window manager
may have various results, for example having dialogs positioned below
the main window,

The window property used by subwindows to point to their mainwindows is
called WM_TRANSIENT_FOR. It can be seen by running
'xprop | grep WM_TRANSIENT_FOR' and clicking on a window. If the property
is not present, the window does not (claim to) have any mainwindow.
If the property is present, it's value is the window id of its main window;
window id of any window can be found out by running 'xwininfo'. A window
having WM_TRANSIENT_FOR poiting to another window is said to be transient
for that window.

In some cases, the WM_TRANSIENT_FOR property may not point to any other
existing window, having value of 0, or pointing to the screen number
('xwininfo -root'). These special values mean that the window is transient
for all other windows in its window group. This should be used only
in rare cases, everytime a specific main window is known, WM_TRANSIENT_FOR
should be pointing to it instead of using one of these special values.
(The explanation why is beyond the scope of this document - just accept it
as a fact.)

With Qt, the WM_TRANSIENT_FOR property is set by Qt automatically, based
on the toplevel widget's parent. If the toplevel widget is of a normal
type (i.e. not a dialog, toolbar, etc.), Qt doesn't set WM_TRANSIENT_FOR
on it. For special widgets, such as dialogs, WM_TRANSIENT_FOR is set
to point to the widget's parent, if it has a specific parent, otherwise
WM_TRANSIENT_FOR points to the root window.

As already said above, WM_TRANSIENT_FOR poiting to the root window should
be usually avoided, so everytime the widget's main widget is known, the widget
should get it passed as a parent in its constructor.
(TODO KDialog etc. classes should not have a default argument for the parent
argument, and comments like 'just pass 0 as the parent' should go.)



Focus stealing prevention:
==========================

Since KDE3.2 KWin has a feature called focus stealing prevention. As the name
suggests, it prevents unexpected changes of focus. With older versions of KWin,
if any application opened a new dialog, it became active, and
if the application's main window was on another virtual desktop, also
the virtual desktop was changed. This was annoying, and also sometimes led
to dialogs mistakenly being closed because they received keyboard input that
was meant for the previously active window.

The basic principle of focus stealing prevention is that the window with most
recent user activity wins. Any window of an application will become active
when being shown only if this application was the most recently used one.
KWin itself, and some of the related tdecore classes should take care
of the common cases, so usually there's no need for any special handling
in applications. Qt/KDE applications, that is. Applications using other
toolkits should in most cases work fine too. If they don't support
the window property _NET_WM_USER_TIME, the window manager may fail to detect
the user timestamp properly, resulting either in other windows becoming active
while the user works with this application, or this application may sometimes
steal focus (this second case should be very rare though).

There are also cases where KDE applications needs special handling. The two
most common cases are when windows relations are not setup properly to make
KWin realize that they belong to the same application, and when the user
activity is not represented by manipulating with the application windows
themselves.

Also note that focus stealing prevention implemented in the window manager
can only help with focus stealing between different applications.
If an application itself suddenly pops up a dialog, KWin cannot do anything about
it, and its the application's job to handle this case.


Window relations:
-----------------

The common case here is when a dialog is shown for an application, but this
dialog is not provided by the application itself, but by some other process.
For example, dialogs with warnings about accepted cookies are provided
by KCookieJar, instead of being shown by Konqueror. In the normal case,
from KWin's point of view the cookie dialog would be an attempt of another
application to show a dialog, and KWin wouldn't allow activation of this
window.

The solution is to tell the window manager about the relation between
the Konqueror main window and the cookie dialog, by making the dialog
point to the mainwindow. Note that this is not special to focus stealing
prevention, subwindows such as dialogs, toolbars and similar should always
point to their mainwindow. See the section on window relations for full
description.

The WM_TRANSIENT_FOR property that's set on dialogs to point to their
mainwindow should in the cookie dialog case point to the Konqueror window
for which it has been shown. This is solved in kcookiejar by including
the window id in the DCOP call. When the cookie dialog is shown, its
WM_TRANSIENT_FOR property is manually set using the XSetTransientForHint()
call (see tdelibs/tdeioslave/http/kcookiejar/kcookiewin.cpp). The arguments
to XSetTransientForHint() call are the X display (i.e. qt_xdisplay()),
the window id on which the WM_TRANSIENT_FOR property is to be set
(i.e. use QWidget::winId()), and the window id of the mainwindow.


Simple short HOWTO:

To put it simply: Let's say you have a daemon application that has
DCOP call "showDialog( QString text )", and when this is called, it shows
a dialog with the given text. This won't work properly with focus stealing
prevention. The DCOP call should be changed to
"showDialog( QString text, long id )". The caller should pass something like
myMainWindow->winId() as the second argument. In the daemon, before
the dialog is shown, a call to XSetTransientHint() should be added:

XSetTransientForHint( qt_xdisplay(), dialog->winId(), id_of_mainwindow );

That's it.

Non-standard user activity:
---------------------------

The most common case in KDE will be DCOP calls. For example, KDesktop's DCOP
call "KDesktopIface popupExecuteCommand". Executing this DCOP call e.g.
from Konsole as 'dcop kdesktop KDesktopIface popupExecuteCommand" will lead
to showing the minicli, but the last user activity timestamp gained from events
sent by X server will be older than user activity timestamp of Konsole, and
would normally result in minicli not being active. Therefore, before showing
the minicli, kdesktop needs to call TDEApplication::updateUserTimestamp().

However, this shouldn't be done with all DCOP calls. If a DCOP call is not
a result of direct user action, calling TDEApplication::updateUserTimestamp()
would lead to focus stealing. For example, let's assume for a moment
that KMail would use this DCOP call in case it detects the modem is not
connected, allowing to you to start KPPP or whatever tool you use. If KMail
would be configured to check mail every 10 minutes, this would lead to minicli
possibly suddenly showing up at every check. Basically, doing the above change
to kdesktop's minicli means that the popupExecuteCommand() DCOP call is only
for user scripting. (TODO write about focus transferring?)

Simply said, TDEApplication::updateUserTimestamp() should be called only
as a result of user action. Unfortunately, I'm not aware of any universal
way how to handle this, so every case will have to be considered separately.