Chartjs-How to get specific co-ordinate along Chartjs donut arc

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You can get points on a circle with the formula

x = radius*sin(angle), y = radius*cos(angle)

So I suppose in your code you could do something like

const donutArc = {
    id: 'donutArc',
    afterDraw: (chart) => {
    const { ctx, data: { datasets }, } = chart;     
    datasets.forEach((dataset, i) =>{
        chart.getDatasetMeta(i).data.forEach((arc, j) => {
            r1 = arc.innerRadius
            r2 = arc.outerRadius
            xinner = r1*Math.sin(arc.startAngle)
            yinner = r1*Math.cos(arc.startAngle)
            xouter = r2*Math.sin(arc.startAngle)
            youter = r2*Math.cos(arc.startAngle)
            // then I guess here you would draw something
            })
        })
    }
}

This is assuming the origin of the graph is (0,0) and thatstartAngle, outerRadius and innerRadius are what they would appear to be

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