javascript - Chartjs tooltip anchor point position on bar charts - Stack Overflow

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I have a bar chart using Chartjs, with a fixed y-axis max. Sometimes the data can exceed the max, but the hover tooltip is always anchored to the top of the bars so it cannot be seen. The tooltips' position option does not really work for me.

So, is there a way to display the tooltip at the bottom of the bars? Or can it follow the hovering mouse cursor like canvasjs?

var ctx = document.getElementById("chart").getContext("2d");
var barChart = new Chart(ctx, {
    type: 'bar',
    options: {
        scales: {
            yAxes: [{
                display: true,
                ticks: {
                    min: 0,
                    max: 120
                },
            }],
        },
        tooltips: {
            // position: 'nearest',
            position: 'average',
        },
        legend: {
            display: false
        }
    },
    data: {
        labels: ["A", "B", "C", "D"],
        datasets: [{
            label: "Data Set 1",
            backgroundColor: [
                '#44b2d7',
                '#44b2d7',
                '#44b2d7',
                '#44b2d7',
            ],
            borderColor: [
                '#44b2d7',
                '#44b2d7',
                '#44b2d7',
                '#44b2d7'
            ],
            borderWidth: 0,
            data: [131, 65, 165, 85]
        }]
    }
});

<script src=".js/2.5.0/Chart.min.js"></script>
<canvas id="chart" height="180"></canvas>

I have a bar chart using Chartjs, with a fixed y-axis max. Sometimes the data can exceed the max, but the hover tooltip is always anchored to the top of the bars so it cannot be seen. The tooltips' position option does not really work for me.

So, is there a way to display the tooltip at the bottom of the bars? Or can it follow the hovering mouse cursor like canvasjs?

var ctx = document.getElementById("chart").getContext("2d");
var barChart = new Chart(ctx, {
    type: 'bar',
    options: {
        scales: {
            yAxes: [{
                display: true,
                ticks: {
                    min: 0,
                    max: 120
                },
            }],
        },
        tooltips: {
            // position: 'nearest',
            position: 'average',
        },
        legend: {
            display: false
        }
    },
    data: {
        labels: ["A", "B", "C", "D"],
        datasets: [{
            label: "Data Set 1",
            backgroundColor: [
                '#44b2d7',
                '#44b2d7',
                '#44b2d7',
                '#44b2d7',
            ],
            borderColor: [
                '#44b2d7',
                '#44b2d7',
                '#44b2d7',
                '#44b2d7'
            ],
            borderWidth: 0,
            data: [131, 65, 165, 85]
        }]
    }
});

<script src="https://cdnjs.cloudflare./ajax/libs/Chart.js/2.5.0/Chart.min.js"></script>
<canvas id="chart" height="180"></canvas>

• javascript
• chart.js

Share Improve this question Follow edited Feb 23, 2019 at 20:54 Luobster asked Feb 21, 2019 at 22:40 LuobsterLuobster 3733 silver badges1111 bronze badges 1

• Seems there is a bug with SO's snippet like this one. Please go to full page. – Luobster Commented Feb 21, 2019 at 23:00

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 5

New modes can be defined by adding functions to the Chart.Tooltip.positioners map. You can create your custom postitioning like in the Doc of chartjs:

    Chart.Tooltip.positioners.custom = function(elements, eventPosition) {
    /** @type {Chart.Tooltip} */
    var tooltip = this;

    /* ... */

    return {
        x: eventPosition.x,
        y: eventPosition.y
    };
}

you need to set your custom function into your options when rendering your chart:

tooltips: { 
            position : 'custom',   //<-- important same name as your function above      
            callbacks: {
              label: function(tooltipItem, data) {
               var label = Math.floor(tooltipItem.yLabel*100)/100+" "+data.datasets[tooltipItem.datasetIndex].label;
               return label;
              }
            }
          }

Look my full Fiddle example.

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