Method insertLegend

3rdparty/qwt/src/qwt_plot.cpp:927–1009

! \brief Insert a legend If the position legend is \c QwtPlot::LeftLegend or \c QwtPlot::RightLegend the legend will be organized in one column from top to down. Otherwise the legend items will be placed in a table with a best fit number of columns from left to right. insertLegend() will set the plot widget as parent for the legend. The legend will be deleted in the destruct

      QwtPlotLayout::setLegendPosition()
 */
void QwtPlot::insertLegend( QwtAbstractLegend* legend,
    QwtPlot::LegendPosition pos, double ratio )
{
    m_data->layout->setLegendPosition( pos, ratio );

    if ( legend != m_data->legend )
    {
        if ( m_data->legend && m_data->legend->parent() == this )
            delete m_data->legend;

        m_data->legend = legend;

        if ( m_data->legend )
        {
            connect(
                this, SIGNAL(legendDataChanged(QVariant,QList<QwtLegendData>)),
                m_data->legend, SLOT(updateLegend(QVariant,QList<QwtLegendData>))
                );

            if ( m_data->legend->parent() != this )
                m_data->legend->setParent( this );

            qwtEnableLegendItems( this, false );
            updateLegend();
            qwtEnableLegendItems( this, true );

            QwtLegend* lgd = qobject_cast< QwtLegend* >( legend );
            if ( lgd )
            {
                switch ( m_data->layout->legendPosition() )
                {
                    case LeftLegend:
                    case RightLegend:
                    {
                        if ( lgd->maxColumns() == 0     )
                            lgd->setMaxColumns( 1 ); // 1 column: align vertical
                        break;
                    }
                    case TopLegend:
                    case BottomLegend:
                    {
                        lgd->setMaxColumns( 0 ); // unlimited
                        break;
                    }
                    default:
                        break;
                }
            }

            QWidget* previousInChain = NULL;
            switch ( m_data->layout->legendPosition() )
            {
                case LeftLegend:
                {
                    const QwtAxisId axisId( QwtAxis::XTop );
                    previousInChain = axisWidget( axisId );
                    break;
                }