timeline_delegate.h

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#ifndef TIMELINE_DELEGATE_H
#define TIMELINE_DELEGATE_H
 
/*
 * @file Timeline delegate.
 *
 * QStyledItemDelegate subclass that will draw a timeline indicator for
 * the specified value.
 *
 * This is intended to be used in QTreeWidgets to show timelines, e.g. for
 * conversations.
 * To use it, first call setItemDelegate:
 *
 *   myTreeWidget()->setItemDelegateForColumn(col_time_start_, new TimelineDelegate());
 *
 * Then, for each QTreeWidgetItem, set or return a timeline_span for the start and end
 * of the timeline in pixels relative to the column width.
 *
 *   setData(col_start_, Qt::UserRole, start_span);
 *   setData(col_end_, Qt::UserRole, end_span);
 *
 */
 
#include <QStyledItemDelegate>
 
// Pixels are relative to item rect and will be clipped.
struct timeline_span {
    int start;
    int width;
 
    double startTime;
    double stopTime;
    double minRelTime;
    double maxRelTime;
 
    int colStart;
    int colDuration;
};
 
Q_DECLARE_METATYPE(timeline_span)
 
class TimelineDelegate : public QStyledItemDelegate
{
public:
    TimelineDelegate(QWidget *parent = 0);
 
    void setDataRole(int role);
 
protected:
    void paint(QPainter *painter, const QStyleOptionViewItem &option,
               const QModelIndex &index) const;
private:
 
    int _dataRole;
};
 
#endif // TIMELINE_DELEGATE_H