如何在angular中更改条形图的图例

<ngx-charts-bar-vertical
  [view]="view"
  [scheme]="colorScheme"
  [results]="chartData"
  [xAxis]="showXAxis"
  [yAxis]="showYAxis"
  [legend]="showLegend"
  [legendPosition]="legendPosition"
  [showXAxisLabel]="showXAxisLabel"
  [showYAxisLabel]="showYAxisLabel"
  [xAxisLabel]="xAxisLabel"
  [yAxisLabel]="yAxisLabel">
</ngx-charts-bar-vertical>

import { Component } from '@angular/core';

@Component({
  selector: 'app-bar-chart',
  templateUrl: './bar-chart.component.html',
  styleUrls: ['./bar-chart.component.css']
})
export class BarChartComponent {
  view: any[] = [700, 400];
  colorScheme = {
    domain: ['#5AA454', '#A10A28', '#C7B42C', '#AAAAAA']
  };
  chartData = [
    {
      name: 'Series 1',
      value: 100
    },
    {
      name: 'Series 2',
      value: 200
    },
    {
      name: 'Series 3',
      value: 150
    },
    {
      name: 'Series 4',
      value: 50
    }
  ];
  showXAxis = true;
  showYAxis = true;
  showLegend = true;
  legendPosition = 'below';
  showXAxisLabel = true;
  showYAxisLabel = true;
  xAxisLabel = 'X Axis';
  yAxisLabel = 'Y Axis';
}