NAME

       QwtAbstractLegend - Abstract base class for legend widgets.

SYNOPSIS

       #include <qwt_abstract_legend.h>

       Inherits QFrame.

       Inherited by QwtLegend.

   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:
           parent Parent 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:
           painter Painter
           rect Bounding rectangle
           fillBackground When 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:
           orientation Orientation

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

Author

       Generated automatically by Doxygen for Qwt User's Guide from the source code.

Version 6.1.4                                    Wed Jan 2 2019                             QwtAbstractLegend(3)