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/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\page restoring-geometry.html
\title Restoring a Window's Geometry
\brief How to save & restore window geometry.
\ingroup best-practices
This document describes how to save and restore a \l{Window
Geometry}{window's geometry} using the geometry properties. On
Windows, this is basically storing the result of
QWidget::geometry() and calling QWidget::setGeometry() in the next
session before calling \l{QWidget::show()}{show()}.
On X11, this might not work because an invisible window does not
have a frame yet. The window manager will decorate the window
later. When this happens, the window shifts towards the
bottom/right corner of the screen depending on the size of the
decoration frame. Although X provides a way to avoid this shift,
some window managers fail to implement this feature.
Since version 4.2, Qt provides functions that saves and restores a
window's geometry and state for you. QWidget::saveGeometry()
saves the window geometry and maximized/fullscreen state, while
QWidget::restoreGeometry() restores it. The restore function also
checks if the restored geometry is outside the available screen
geometry, and modifies it as appropriate if it is:
\snippet doc/src/snippets/code/src_gui_widgets_qmainwindow.cpp 0
\snippet doc/src/snippets/code/src_gui_widgets_qmainwindow.cpp 1
If those functions are not available or cannot be used, then a
workaround is to call \l{QWidget::setGeometry()}{setGeometry()}
after \l{QWidget::show()}{show()}. This has the two disadvantages
that the widget appears at a wrong place for a millisecond
(results in flashing) and that currently only every second window
manager gets it right. A safer solution is to store both
\l{QWidget::pos()}{pos()} and \l{QWidget::size()}{size()} and to
restore the geometry using \l{QWidget::resize()} and
\l{QWidget::move()}{move()} before calling
\l{QWidget::show()}{show()}, as demonstrated in the
\l{mainwindows/application}{Application} example.
*/
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