pieview.h Example File

 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of The Qt Company Ltd nor the names of its
 **     contributors may be used to endorse or promote products derived
 **     from this software without specific prior written permission.
 **
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #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);
     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