qpainterstateguard.h

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// Copyright (C) 2024 Christian Ehrlicher <ch.ehrlicher@gmx.de>

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

// Qt-Security score:significant reason:default

#ifndef QPAINTERSTATEGUARD_H

#define QPAINTERSTATEGUARD_H

#include <QtCore/qtclasshelpermacros.h>

#include <QtGui/qpainter.h>

QT_BEGIN_NAMESPACE

class QPainterStateGuard

    Q_DISABLE_COPY(QPainterStateGuard)

public:

    enum class InitialState : quint8 {

        Save,

        NoSave,

};

    QPainterStateGuard(QPainterStateGuard &&other) noexcept

        : m_painter(std::exchange(other.m_painter, nullptr))

        , m_level(std::exchange(other.m_level, 0))

{}

    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QPainterStateGuard)

    void swap(QPainterStateGuard &other) noexcept

        qt_ptr_swap(m_painter, other.m_painter);

        std::swap(m_level, other.m_level);

    Q_NODISCARD_CTOR

    explicit QPainterStateGuard(QPainter *painter, InitialState state = InitialState::Save)

        : m_painter(painter)

        verifyPainter();

        if (state == InitialState::Save)

            save();

    ~QPainterStateGuard()

        while (m_level > 0)

            restore();

    void save()

        verifyPainter();

        m_painter->save();

        ++m_level;

    void restore()

        verifyPainter();

        Q_ASSERT(m_level > 0);

        --m_level;

        m_painter->restore();

private:

    void verifyPainter()

        Q_ASSERT(m_painter);

    QPainter *m_painter;

    int m_level = 0;

};

QT_END_NAMESPACE

#endif  // QPAINTERSTATEGUARD_H