PDF Viewer Example

 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

 #include "mainwindow.h"
 #include "ui_mainwindow.h"

 #include "zoomselector.h"

 #include <QFileDialog>
 #include <QMessageBox>
 #include <QSpinBox>
 #include <QPdfBookmarkModel>
 #include <QPdfDocument>
 #include <QPdfPageNavigator>
 #include <QtMath>

 const qreal zoomMultiplier = qSqrt(2.0);

 Q_LOGGING_CATEGORY(lcExample, "qt.examples.pdfviewer")

 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
     , ui(new Ui::MainWindow)
     , m_zoomSelector(new ZoomSelector(this))
     , m_pageSelector(new QSpinBox(this))
     , m_document(new QPdfDocument(this))
 {
     ui->setupUi(this);

     m_zoomSelector->setMaximumWidth(150);
     ui->mainToolBar->insertWidget(ui->actionZoom_In, m_zoomSelector);

     ui->mainToolBar->insertWidget(ui->actionForward, m_pageSelector);
     connect(m_pageSelector, &QSpinBox::valueChanged, this, &MainWindow::pageSelected);
     auto nav = ui->pdfView->pageNavigator();
     connect(nav, &QPdfPageNavigator::currentPageChanged, m_pageSelector, &QSpinBox::setValue);
     connect(nav, &QPdfPageNavigator::backAvailableChanged, ui->actionBack, &QAction::setEnabled);
     connect(nav, &QPdfPageNavigator::forwardAvailableChanged, ui->actionForward, &QAction::setEnabled);

     connect(m_zoomSelector, &ZoomSelector::zoomModeChanged, ui->pdfView, &QPdfView::setZoomMode);
     connect(m_zoomSelector, &ZoomSelector::zoomFactorChanged, ui->pdfView, &QPdfView::setZoomFactor);
     m_zoomSelector->reset();

     QPdfBookmarkModel *bookmarkModel = new QPdfBookmarkModel(this);
     bookmarkModel->setDocument(m_document);

     ui->bookmarkView->setModel(bookmarkModel);
     connect(ui->bookmarkView, SIGNAL(activated(QModelIndex)), this, SLOT(bookmarkSelected(QModelIndex)));

     ui->tabWidget->setTabEnabled(1, false); // disable 'Pages' tab for now

     ui->pdfView->setDocument(m_document);

     connect(ui->pdfView, &QPdfView::zoomFactorChanged,
             m_zoomSelector, &ZoomSelector::setZoomFactor);
 }

 MainWindow::~MainWindow()
 {
     delete ui;
 }

 void MainWindow::open(const QUrl &docLocation)
 {
     if (docLocation.isLocalFile()) {
         m_document->load(docLocation.toLocalFile());
         const auto documentTitle = m_document->metaData(QPdfDocument::MetaDataField::Title).toString();
         setWindowTitle(!documentTitle.isEmpty() ? documentTitle : QStringLiteral("PDF Viewer"));
         pageSelected(0);
         m_pageSelector->setMaximum(m_document->pageCount() - 1);
     } else {
         qCDebug(lcExample) << docLocation << "is not a valid local file";
         QMessageBox::critical(this, tr("Failed to open"), tr("%1 is not a valid local file").arg(docLocation.toString()));
     }
     qCDebug(lcExample) << docLocation;
 }

 void MainWindow::bookmarkSelected(const QModelIndex &index)
 {
     if (!index.isValid())
         return;

     const int page = index.data(int(QPdfBookmarkModel::Role::Page)).toInt();
     const qreal zoomLevel = index.data(int(QPdfBookmarkModel::Role::Level)).toReal();
     ui->pdfView->pageNavigator()->jump(page, {}, zoomLevel);
 }

 void MainWindow::pageSelected(int page)
 {
     auto nav = ui->pdfView->pageNavigator();
     nav->jump(page, {}, nav->currentZoom());
 }

 void MainWindow::on_actionOpen_triggered()
 {
     QUrl toOpen = QFileDialog::getOpenFileUrl(this, tr("Choose a PDF"), QUrl(), "Portable Documents (*.pdf)");
     if (toOpen.isValid())
         open(toOpen);
 }

 void MainWindow::on_actionQuit_triggered()
 {
     QApplication::quit();
 }

 void MainWindow::on_actionAbout_triggered()
 {
     QMessageBox::about(this, tr("About PdfViewer"),
         tr("An example using QPdfDocument"));
 }

 void MainWindow::on_actionAbout_Qt_triggered()
 {
     QMessageBox::aboutQt(this);
 }

 void MainWindow::on_actionZoom_In_triggered()
 {
     ui->pdfView->setZoomFactor(ui->pdfView->zoomFactor() * zoomMultiplier);
 }

 void MainWindow::on_actionZoom_Out_triggered()
 {
     ui->pdfView->setZoomFactor(ui->pdfView->zoomFactor() / zoomMultiplier);
 }

 void MainWindow::on_actionPrevious_Page_triggered()
 {
     auto nav = ui->pdfView->pageNavigator();
     nav->jump(nav->currentPage() - 1, {}, nav->currentZoom());
 }

 void MainWindow::on_actionNext_Page_triggered()
 {
     auto nav = ui->pdfView->pageNavigator();
     nav->jump(nav->currentPage() + 1, {}, nav->currentZoom());
 }

 void MainWindow::on_actionContinuous_triggered()
 {
     ui->pdfView->setPageMode(ui->actionContinuous->isChecked() ?
                                  QPdfView::PageMode::MultiPage :
                                  QPdfView::PageMode::SinglePage);
 }

 void MainWindow::on_actionBack_triggered()
 {
     ui->pdfView->pageNavigator()->back();
 }

 void MainWindow::on_actionForward_triggered()
 {
     ui->pdfView->pageNavigator()->forward();
 }