Ng2-charts: Cannot get the real chart object

[telion2]

Goal:
I want to access the Chartjs object where I can do stuff like:
this.chart.chart.ctx.drawImage(...);
this.chart.chart.height;
or this.chart.chart.innerRadius.
and so on.
in #776 I learned to use @ViewChild('mycanvas') chart: BaseChartDirective;
However I dont really get access to those mentioned options as this.chart.chart is undefined.

Reproduction:
I have adjusted https://stackblitz.com/edit/ng2-charts-doughnut-template :

import { Component, OnInit,ViewChild } from '@angular/core';
import { ChartType } from 'chart.js';
import { MultiDataSet, Label } from 'ng2-charts';
import { BaseChartDirective } from 'ng2-charts';
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
// Doughnut
  public doughnutChartLabels: Label[] = ['Download Sales', 'In-Store Sales', 'Mail-Order Sales'];
  public doughnutChartData: MultiDataSet = [
    [350, 450, 100],
    [50, 150, 120],
    [250, 130, 70],
  ];
 public doughnutChartType: ChartType = 'doughnut';

  @ViewChild('mycanvas') chart: BaseChartDirective;  //<------This is important
  constructor() { }
  ngOnInit() {
    console.log(JSON.stringify(this.chart)); 
  }
  ngAfterViewInit(): void {
    console.log(JSON.stringify(this.chart)); 
    console.log(this.chart.chart);                           //<-----undefined
  }
}

Also the html-canvas tag got the '#mycanvas' element.

My ultimate Goal is to get a picture to be rendered inside a doughnut chart.
I got that to work with a plugin (following this: https://stackoverflow.com/a/55727282) however I couldnt find a way to change the picture on runtime. So I thought I will rewrite everything by accessing the chart.js object.

[telion2]

I found that the way how I did the '#mycanvas' was wrong:

wrong: 
<canvas baseChart
        #mycanvas                            //<------add: ="base-chart"
        style="position: center"
        [data]="chartData"
        [legend]="false"
        [labels]="chartLabels"
        [chartType]="doughnutChartType"
        [plugins]="doughnutChartPlugins"
></canvas>
correct: 
<canvas baseChart
        #mycanvas="base-chart"     //<------add: ="base-chart"
        style="position: center"
        [data]="chartData"
        [legend]="false"
        [labels]="chartLabels"
        [chartType]="doughnutChartType"
        [plugins]="doughnutChartPlugins"
></canvas>

Aparently the difference is that '#mycanvas' without the base-chart value is only returning the nativeElement, while with the value would map it to the class.