virtual double legendSize(double value, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is) const =0
Returns the size of the legend item for the diagram corresponding to a specified value.
virtual void renderDiagram(const QgsFeature &feature, QgsRenderContext &c, const QgsDiagramSettings &s, QPointF position)=0
Draws the diagram at the given position (in pixel coordinates)
virtual QSizeF diagramSize(const QgsAttributes &attributes, const QgsRenderContext &c, const QgsDiagramSettings &s)=0
Returns the size in map units the diagram will use to render.
Contains information about the context of a rendering operation.