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

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