如何更改primefaces chartjs中的轴字体

我正在使用PrimeFaces 7,并尝试使用Chart.js中的条形图,如下所示:

代码:

<p:barChart  widgetVar="cfg" model="#{dashboardBean.barModel}" style="width:500px;height:348px;"/>

private void createBarModel(Map<String, Double> delegatesMap) {

        barModel = new BarChartModel();
        barModel.setExtender("skinBar");
        ChartData data = new ChartData();

        BarChartDataSet barDataSet = new BarChartDataSet();
        barDataSet.setLabel("");

        List<Number> valuesList = new ArrayList<>();
        List<String> labelsList = new ArrayList<>();
        List<String> backgroundColorList = new ArrayList<>();

        for (Map.Entry<String, Double> entry : delegatesMap.entrySet()) {
            labelsList.add(entry.getKey());
            valuesList.add(entry.getValue());
            backgroundColorList.add("#00bcd4");
        }

        barDataSet.setData(valuesList);
        barDataSet.setBackgroundColor(backgroundColorList);



        data.addChartDataSet(barDataSet);
        data.setLabels(labelsList);
        barModel.setData(data);

        // Options
        BarChartOptions options = new BarChartOptions();
        CartesianScales cScales = new CartesianScales();
        CartesianLinearAxes linearAxes = new CartesianLinearAxes();
        CartesianLinearTicks ticks = new CartesianLinearTicks();
        ticks.setBeginAtZero(true);
        linearAxes.setTicks(ticks);
        cScales.addYAxesData(linearAxes);
        options.setScales(cScales);

        Title title = new Title();
        title.setDisplay(true);
        title.setText("Sales Income");
        title.setFontFamily("Tahoma");
        options.setTitle(title);

        Legend legend = new Legend();
        legend.setDisplay(false);
        options.setLegend(legend);

        barModel.setOptions(options);

    }

我正在尝试使用extender函数更改axis字体系列,如下所示:

function skinBar() {
        var options = $.extend(true, {}, this.cfg.config);

    options = {
            scales: {
                yAxes: [{
                    ticks: {
                        fontFamily: 'Tahoma',
                        fontSize:40
                    }
                }],
                xAxes: [{
                    ticks: {
                        fontFamily: 'Tahoma',
                        fontSize:40
                    }
                }]
            }
        }


       $.extend(true, this.cfg.config, options);
    }

但它不起作用。我怎样才能修好它?