QwtAbstractLegend Class Reference

Abstract base class for legend widgets. More...

#include <qwt_abstract_legend.h>

Inheritance diagram for QwtAbstractLegend:

Public Slots
virtual void	updateLegend (const QVariant &itemInfo, const QList< QwtLegendData > &data)=0
	Update the entries for a plot item. More...

Public Member Functions
	QwtAbstractLegend (QWidget *parent=NULL)
virtual	~QwtAbstractLegend ()
	Destructor.
virtual void	renderLegend (QPainter *painter, const QRectF &rect, bool fillBackground) const =0
virtual bool	isEmpty () const =0
virtual int	scrollExtent (Qt::Orientation) const

Detailed Description

Abstract base class for legend widgets.

Legends, that need to be under control of the QwtPlot layout system need to be derived from QwtAbstractLegend.

Note

Other type of legends can be implemented by connecting to the QwtPlot::legendDataChanged() signal. But as these legends are unknown to the plot layout system the layout code ( on screen and for QwtPlotRenderer ) need to be organized in application code.

See also

QwtLegend

Constructor & Destructor Documentation

QwtAbstractLegend()

QwtAbstractLegend::QwtAbstractLegend ( QWidget *  parent = NULL )

explicit

Constructor

Parameters

parent

Parent widget

Member Function Documentation

isEmpty()

virtual bool QwtAbstractLegend::isEmpty ( ) const

pure virtual

Returns

True, when no plot item is inserted

Implemented in QwtLegend.

renderLegend()

virtual void QwtAbstractLegend::renderLegend ( QPainter *  painter, const QRectF &  rect, bool  fillBackground  ) const

pure virtual

Render the legend into a given rectangle.

Parameters

painter	Painter
rect	Bounding rectangle
fillBackground	When true, fill rect with the widget background

See also

renderLegend() is used by QwtPlotRenderer

Implemented in QwtLegend.

scrollExtent()

int QwtAbstractLegend::scrollExtent ( Qt::Orientation  orientation ) const

virtual

Return the extent, that is needed for elements to scroll the legend ( usually scrollbars ),

Parameters

orientation

Orientation

Returns

Extent of the corresponding scroll element

Reimplemented in QwtLegend.

updateLegend

virtual void QwtAbstractLegend::updateLegend ( const QVariant &  itemInfo, const QList< QwtLegendData > &  data  )

pure virtualslot

Update the entries for a plot item.

Parameters

itemInfo	Info about an item
data	List of legend entry attributes for the item