PDF4QT/Pdf4QtLib/sources/pdfpagenavigation.h

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// Copyright (C) 2020 Jakub Melka
//
// This file is part of Pdf4Qt.
//
// Pdf4Qt is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Pdf4Qt is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Pdf4Qt. If not, see <https://www.gnu.org/licenses/>.
#ifndef PDFPAGENAVIGATION_H
#define PDFPAGENAVIGATION_H
#include "pdfpage.h"
#include "pdfcatalog.h"
#include "pdfdocument.h"
#include "pdfpagetransition.h"
#include "pdfaction.h"
#include <QObject>
namespace pdf
{
/// Page navigation node for subpage navigation.
class PDFNavigationNode
{
public:
explicit PDFNavigationNode() = default;
PDFActionPtr getPreviousAction() const;
PDFActionPtr getNextAction() const;
PDFObjectReference getPreviousNode() const;
PDFObjectReference getNextNode() const;
PDFReal getDuration() const;
/// Parses navigation node. If error occurs, then empty optional
/// item is returned.
/// \param storage Storage
/// \param object Object
static std::optional<PDFNavigationNode> parse(const PDFObjectStorage* storage, PDFObject object);
private:
PDFActionPtr m_previousAction;
PDFActionPtr m_nextAction;
PDFObjectReference m_previousNode;
PDFObjectReference m_nextNode;
PDFReal m_duration = 0.0;
};
/// Navigation object, which helps to navigate trough document.
/// It also handles subpage navigation, if subpage navigation
/// steps are present.
class Pdf4QtLIBSHARED_EXPORT PDFPageNavigation : public QObject
{
Q_OBJECT
public:
explicit PDFPageNavigation(const PDFDocument* document, QObject* parent);
/// Navigates to specified page. Page index must be valid.
/// \param pageIndex Page index
void navigateToPage(size_t pageIndex);
/// Navigates forward. If subpage navigation is present,
/// navigates to next page navigation node. Otherwise
/// navigates to next page.
void navigateForward();
/// Navigates backward. If subpage navigation is present,
/// navigates to previous page navigation node. Otherwise
/// navigates to previous page.
void navigateBackward();
signals:
/// This signal is emitted, if subpage navigation is requested.
void actionTriggered(const PDFAction* action);
/// This signal is emitted, if navigation to another page is required.
/// Page index is always valid. If document contains no pages, then
/// this signal is never emitted. Also, transition is always a valid
/// object (not null pointer).
void pageChangeRequest(const size_t pageIndex, const PDFPageTransition* transition);
private:
enum class Direction
{
Forward, ///< We navigate forward
Backward ///< We navigate backward
};
void executeNavigationNode(Direction direction);
size_t m_currentPageIndex;
std::optional<PDFNavigationNode> m_currentNavigationNode;
PDFPageTransition m_transition;
const PDFDocument* m_document;
};
} // namespace pdf
#endif // PDFPAGENAVIGATION_H