10 #ifndef QWT_ABSTRACT_LEGEND_H    11 #define QWT_ABSTRACT_LEGEND_H    13 #include "qwt_global.h"    14 #include "qwt_legend_data.h"    51     virtual void renderLegend( QPainter *painter, 
    52         const QRectF &rect, 
bool fillBackground ) 
const = 0;
    55     virtual bool isEmpty() 
const = 0;
    57     virtual int scrollExtent( Qt::Orientation ) 
const;
    67     virtual void updateLegend( 
const QVariant &itemInfo, 
    68         const QList<QwtLegendData> &data ) = 0;
 Abstract base class for legend widgets. 
Definition: qwt_abstract_legend.h:34