PDF Viewer Example

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 #ifndef ZOOMSELECTOR_H
 #define ZOOMSELECTOR_H

 #include <QComboBox>
 #include <QPdfView>

 class ZoomSelector : public QComboBox
 {
     Q_OBJECT

 public:
     explicit ZoomSelector(QWidget *parent = nullptr);

 public slots:
     void setZoomFactor(qreal zoomFactor);

     void reset();

 signals:
     void zoomModeChanged(QPdfView::ZoomMode zoomMode);
     void zoomFactorChanged(qreal zoomFactor);

 private slots:
     void onCurrentTextChanged(const QString &text);
 };

 #endif // ZOOMSELECTOR_H