pieview.h Example File

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 #ifndef PIEVIEW_H
 #define PIEVIEW_H

 #include <QAbstractItemView>
 #include <QFont>
 #include <QItemSelection>
 #include <QItemSelectionModel>
 #include <QModelIndex>
 #include <QRect>
 #include <QSize>
 #include <QPoint>
 #include <QWidget>

 class QRubberBand;

 class PieView : public QAbstractItemView
 {
     Q_OBJECT

 public:
     PieView(QWidget *parent = 0);

     QRect visualRect(const QModelIndex &index) const;
     void scrollTo(const QModelIndex &index, ScrollHint hint = EnsureVisible);
     QModelIndex indexAt(const QPoint &point) const;

 protected slots:
     void dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QSet<int> &);
     void rowsInserted(const QModelIndex &parent, int start, int end);
     void rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end);

 protected:
     bool edit(const QModelIndex &index, EditTrigger trigger, QEvent *event);
     QModelIndex moveCursor(QAbstractItemView::CursorAction cursorAction,
                            Qt::KeyboardModifiers modifiers);

     int horizontalOffset() const;
     int verticalOffset() const;

     bool isIndexHidden(const QModelIndex &index) const;

     void setSelection(const QRect&, QItemSelectionModel::SelectionFlags command);

     void mousePressEvent(QMouseEvent *event);

     void mouseMoveEvent(QMouseEvent *event);
     void mouseReleaseEvent(QMouseEvent *event);

     void paintEvent(QPaintEvent *event);
     void resizeEvent(QResizeEvent *event);
     void scrollContentsBy(int dx, int dy);

     QRegion visualRegionForSelection(const QItemSelection &selection) const;

 private:
     QRect itemRect(const QModelIndex &item) const;
     QRegion itemRegion(const QModelIndex &index) const;
     int rows(const QModelIndex &index = QModelIndex()) const;
     void updateGeometries();

     int margin;
     int totalSize;
     int pieSize;
     int validItems;
     double totalValue;
     QPoint origin;
     QRubberBand *rubberBand;
 };

 #endif