QwtAbstractLegend − Abstract base class for legend widgets.
#include <qwt_abstract_legend.h>
Inherits QFrame.
Inherited by QwtLegend.
virtual void
updateLegend (const QVariant &itemInfo, const
QList< QwtLegendData > &data)=0
Update the entries for a plot item.
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
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
Definition at line 34 of file qwt_abstract_legend.h.
Constructor
Parameters
parent Parent widget
Definition at line 18 of file qwt_abstract_legend.cpp.
Destructor.
Definition at line 24 of file qwt_abstract_legend.cpp.
Returns
True, when no plot item is inserted
Implemented in QwtLegend.
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.
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.
Definition at line 35 of file qwt_abstract_legend.cpp.
Update the entries for a plot item.
Parameters
itemInfo Info about an
item
data List of legend entry attributes for the item
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