1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
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
\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.
*/
|
