Qwt User's Guide
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.

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 ( QWidget *  parent = NULL) [explicit]

Constructor

Parameters:
parentParent widget

Member Function Documentation

virtual bool QwtAbstractLegend::isEmpty ( ) const [pure virtual]
Returns:
True, when no plot item is inserted

Implemented in QwtLegend.

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

Render the legend into a given rectangle.

Parameters:
painterPainter
rectBounding rectangle
fillBackgroundWhen true, fill rect with the widget background
See also:
renderLegend() is used by QwtPlotRenderer

Implemented in QwtLegend.

int QwtAbstractLegend::scrollExtent ( Qt::Orientation  orientation) const [virtual]

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

Parameters:
orientationOrientation
Returns:
Extent of the corresponding scroll element

Reimplemented in QwtLegend.

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

Update the entries for a plot item.

Parameters:
itemInfoInfo about an item
dataList of legend entry attributes for the item

Implemented in QwtLegend.

List of all members.

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