QtCharts 图例图标大小怎么设置

练习QtChart图例显示的时候发现图例太小了，如下图所示

设置图例大小后，有所改善，但是没有达到我想要的效果，下图是我重设字体的效果

如何设置前面的矩形颜色显示的地方大于字体，达到的效果如下所示

//头文件
#pragma once

#include <QScatterSeries>
#include <QtCharts/QChartView>

QT_CHARTS_USE_NAMESPACE

class TestChartView :public QChartView
{
    Q_OBJECT

public:
    explicit TestChartView(QWidget *parent = Q_NULLPTR);
    ~TestChartView();
private:
    QList<QScatterSeries *>m_series;
};
//cpp文件
#include "testchartview.h"

#include <QLegend>
TestChartView::TestChartView(QWidget *parent)
    : QChartView(new QChart(),parent)
{
    QStringList list;
    list << "0"
        << "2"
        << "5"
        << "10"
        << "20"
        << "50"
        << "100"
        << "200"
        << ">200";
    QList<QRgb> reg_list;
    reg_list
        << qRgb(255, 255, 200)
        << qRgb(254, 254, 55)
        << qRgb(254, 212, 133)
        << qRgb(55, 254, 55)
        << qRgb(82, 163, 82)
        << qRgb(220, 195, 165)
        << qRgb(180, 79, 57)
        << qRgb(55, 55, 254)
        << qRgb(254, 55, 55);

    int list_siz = list.size();
    m_series.reserve(list_siz);
    QScatterSeries * seric = nullptr;

    setRenderHint(QPainter::Antialiasing);
    
    for (int i = 0; i < list_siz; i++)
    {
        seric = new QScatterSeries(this);

        seric->setName(list.at(i));
        seric->setMarkerShape(QScatterSeries::MarkerShapeRectangle);
        seric->setColor(QColor(reg_list.at(i)));
        chart()->addSeries(seric);
        m_series.push_back(seric);
    }
    QFont font = chart()->legend()->font();
    font.setPointSize(18);
    chart()->legend()->setFont(font);
    chart()->legend()->setAlignment(Qt::AlignRight);

    
    chart()->createDefaultAxes();
    chart()->setDropShadowEnabled(false);
    

}

TestChartView::~TestChartView()
{
}