1// Copyright (C) 2024 Christian Ehrlicher <ch.ehrlicher@gmx.de>
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#include "qpainterstateguard.h"
5
6QT_BEGIN_NAMESPACE
7
8/*!
9 \class QPainterStateGuard
10 \brief The QPainterStateGuard is a RAII convenience class for balanced
11 QPainter::save() and QPainter::restore() calls.
12 \since 6.9
13
14 \inmodule QtGui
15 \ingroup painting
16
17 \reentrant
18
19 \sa QPainter
20
21 QPainterStateGuard should be used everywhere as a replacement for QPainter::save()
22 to make sure that the corresponding QPainter::restore() is called upon finishing
23 of the painting routine to avoid unbalanced calls between those two functions.
24
25 Example with QPainter::save()/QPainter::restore():
26 \snippet code/src_gui_painting_qpainterstateguard.cpp 0
27
28 Example with QPainterStateGuard:
29 \snippet code/src_gui_painting_qpainterstateguard.cpp 1
30*/
31
32/*!
33 \fn QPainterStateGuard::QPainterStateGuard(QPainter *painter, InitialState state = InitialState::Save)
34 Constructs a QPainterStateGuard and calls save() on \a painter if \a state
35 is \c InitialState::Save (which is the default). When QPainterStateGuard is
36 destroyed, restore() is called as often as save() was called to restore the
37 QPainter's state.
38*/
39
40/*!
41 \fn QPainterStateGuard::QPainterStateGuard(QPainterStateGuard &&other)
42
43 Move-constructs a painter state guard from \a other.
44*/
45
46/*!
47 \fn QPainterStateGuard &QPainterStateGuard::operator=(QPainterStateGuard &&other)
48
49 Move-assigns \a other to this painter state guard.
50*/
51
52/*!
53 \fn void QPainterStateGuard::swap(QPainterStateGuard &other)
54
55 Swaps the \a other with this painter state guard. This operation is very
56 fast and never fails.
57*/
58
59/*!
60 \fn QPainterStateGuard::~QPainterStateGuard()
61 Destroys the QPainterStateGuard instance and calls restore() as often as save()
62 was called to restore the QPainter's state.
63*/
64
65/*!
66 \fn void QPainterStateGuard::save()
67 Calls QPainter::save() and increases the internal save/restore counter by one.
68*/
69
70/*!
71 \fn void QPainterStateGuard::restore()
72 Calls QPainter::restore() if the internal save/restore counter is greater than zero.
73
74 \note This function asserts in debug builds if the counter has already reached zero.
75*/
76
77QT_END_NAMESPACE
78

source code of qtbase/src/gui/painting/qpainterstateguard.cpp