.TH "QwtAbstractLegend" 3 "Sun Jul 18 2021" "Version 6.2.0" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtAbstractLegend \- Abstract base class for legend widgets\&.  

.SH SYNOPSIS
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.PP
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\fC#include <qwt_abstract_legend\&.h>\fP
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Inherits QFrame\&.
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Inherited by \fBQwtLegend\fP\&.
.SS "Public Slots"

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.RI "virtual void \fBupdateLegend\fP (const QVariant &itemInfo, const \fBQList\fP< \fBQwtLegendData\fP > &data)=0"
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.RI "Update the entries for a plot item\&. "
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.SS "Public Member Functions"

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.RI "\fBQwtAbstractLegend\fP (QWidget *parent=NULL)"
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.RI "virtual \fB~QwtAbstractLegend\fP ()"
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.RI "Destructor\&. "
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.RI "virtual void \fBrenderLegend\fP (QPainter *painter, const QRectF &rect, bool fillBackground) const =0"
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.RI "virtual bool \fBisEmpty\fP () const =0"
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.RI "virtual int \fBscrollExtent\fP (Qt::Orientation) const"
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.SH "Detailed Description"
.PP 
Abstract base class for legend widgets\&. 

Legends, that need to be under control of the \fBQwtPlot\fP layout system need to be derived from \fBQwtAbstractLegend\fP\&.
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\fBNote\fP
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Other type of legends can be implemented by connecting to the \fBQwtPlot::legendDataChanged()\fP signal\&. But as these legends are unknown to the plot layout system the layout code ( on screen and for \fBQwtPlotRenderer\fP ) need to be organized in application code\&.
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\fBSee also\fP
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\fBQwtLegend\fP 
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Definition at line 34 of file qwt_abstract_legend\&.h\&.
.SH "Constructor & Destructor Documentation"
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.SS "QwtAbstractLegend::QwtAbstractLegend (QWidget * parent = \fCNULL\fP)\fC [explicit]\fP"
Constructor
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\fBParameters\fP
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\fIparent\fP Parent widget 
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Definition at line 18 of file qwt_abstract_legend\&.cpp\&.
.SH "Member Function Documentation"
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.SS "virtual bool QwtAbstractLegend::isEmpty () const\fC [pure virtual]\fP"

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\fBReturns\fP
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True, when no plot item is inserted 
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Implemented in \fBQwtLegend\fP\&.
.SS "virtual void QwtAbstractLegend::renderLegend (QPainter * painter, const QRectF & rect, bool fillBackground) const\fC [pure virtual]\fP"
Render the legend into a given rectangle\&.
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\fBParameters\fP
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\fIpainter\fP Painter 
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\fIrect\fP Bounding rectangle 
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\fIfillBackground\fP When true, fill rect with the widget background
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\fBSee also\fP
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\fBrenderLegend()\fP is used by \fBQwtPlotRenderer\fP 
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Implemented in \fBQwtLegend\fP\&.
.SS "int QwtAbstractLegend::scrollExtent (Qt::Orientation orientation) const\fC [virtual]\fP"
Return the extent, that is needed for elements to scroll the legend ( usually scrollbars ),
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\fBParameters\fP
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\fIorientation\fP Orientation 
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\fBReturns\fP
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Extent of the corresponding scroll element 
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Reimplemented in \fBQwtLegend\fP\&.
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Definition at line 35 of file qwt_abstract_legend\&.cpp\&.
.SS "virtual void QwtAbstractLegend::updateLegend (const QVariant & itemInfo, const \fBQList\fP< \fBQwtLegendData\fP > & data)\fC [pure virtual]\fP, \fC [slot]\fP"

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Update the entries for a plot item\&. 
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\fBParameters\fP
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\fIitemInfo\fP Info about an item 
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\fIdata\fP List of legend entry attributes for the item 
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.SH "Author"
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Generated automatically by Doxygen for Qwt User's Guide from the source code\&.