diff -r dee5afe5301f -r 3f74d0d4af4c doc/src/howtos/restoring-geometry.qdoc --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/doc/src/howtos/restoring-geometry.qdoc Thu Apr 08 14:19:33 2010 +0300 @@ -0,0 +1,82 @@ +/**************************************************************************** +** +** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \page restoring-geometry.html + \title Restoring a Window's 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. +*/