doc/src/howtos/restoring-geometry.qdoc
author Eckhart Koeppen <eckhart.koppen@nokia.com>
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/****************************************************************************
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**
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** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
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** All rights reserved.
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** This file is part of the documentation of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** No Commercial Usage
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** This file contains pre-release code and may not be distributed.
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** You may use this file in accordance with the terms and conditions
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** contained in the Technology Preview License Agreement accompanying
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** this package.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file.  Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** In addition, as a special exception, Nokia gives you certain additional
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** rights.  These rights are described in the Nokia Qt LGPL Exception
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** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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**
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** If you have questions regarding the use of this file, please contact
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** Nokia at qt-info@nokia.com.
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**
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**
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**
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**
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**
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**
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**
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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/*!
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    \page restoring-geometry.html
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    \title Restoring a Window's Geometry
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    \ingroup best-practices
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    This document describes how to save and restore a \l{Window
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    Geometry}{window's geometry} using the geometry properties. On
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    Windows, this is basically storing the result of
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    QWidget::geometry() and calling QWidget::setGeometry() in the next
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    session before calling \l{QWidget::show()}{show()}.
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    On X11, this might not work because an invisible window does not
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    have a frame yet. The window manager will decorate the window
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    later.  When this happens, the window shifts towards the
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    bottom/right corner of the screen depending on the size of the
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    decoration frame.  Although X provides a way to avoid this shift,
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    some window managers fail to implement this feature.
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    Since version 4.2, Qt provides functions that saves and restores a
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    window's geometry and state for you. QWidget::saveGeometry()
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    saves the window geometry and maximized/fullscreen state, while
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    QWidget::restoreGeometry() restores it. The restore function also
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    checks if the restored geometry is outside the available screen
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    geometry, and modifies it as appropriate if it is:
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    \snippet doc/src/snippets/code/src_gui_widgets_qmainwindow.cpp 0
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    \snippet doc/src/snippets/code/src_gui_widgets_qmainwindow.cpp 1
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    If those functions are not available or cannot be used, then a
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    workaround is to call \l{QWidget::setGeometry()}{setGeometry()}
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    after \l{QWidget::show()}{show()}. This has the two disadvantages
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    that the widget appears at a wrong place for a millisecond
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    (results in flashing) and that currently only every second window
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    manager gets it right. A safer solution is to store both
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    \l{QWidget::pos()}{pos()} and \l{QWidget::size()}{size()} and to
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    restore the geometry using \l{QWidget::resize()} and
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    \l{QWidget::move()}{move()} before calling
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    \l{QWidget::show()}{show()}, as demonstrated in the
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    \l{mainwindows/application}{Application} example.
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*/