How to fix chart Legends width-height with overflow scroll in ChartJS

Question

I want to create pie chart for my project, so I am using ChartJS for it, but there are some issues with chartJS, If I am work with 10 to 20 data-field that time chart is looks good, But when I am apply more than 50 to 60 data-field in one chart, So that chart is looks smaller instead of legends, and If sometimes data-field is too much than the chart is hide, you can see only legends, chart is gone.

I want to set height or width to that legends and also apply to scrollbar if there is more data.

Here is the fiddle link for your reference

https://jsfiddle.net/KDM1010/5um78rbk/

<canvas id="myChart" width="500" height="300"></canvas>


var ctx = document.getElementById("myChart").getContext('2d');
    var myChart = new Chart(ctx, {
      type: 'pie',
      data: {
        labels: ["lable_1", "lable_2", "lable_3", "lable_4", "lable_5", "lable_6", "lable_7", "lable_8", "lable_9", "lable_10", "lable_11", "lable_12", "lable_13", "lable_14", "lable_15", "lable_16", "lable_17", "lable_18", "lable_19", "lable_20", "lable_21", "lable_22", "lable_23", "lable_24", "lable_25", "lable_26", "lable_27", "lable_28", "lable_29", "lable_30", "lable_31", "lable_32", "lable_33", "lable_34", "lable_35", "lable_36", "lable_37", "lable_38", "lable_39", "lable_40", "lable_41", "lable_42", "lable_43", "lable_44", "lable_45", "lable_46", "lable_47", "lable_48", "lable_49", "lable_50"],
        datasets: [{
          backgroundColor: ["#2ecc71","#3498db","#95a5a6","#9b59b6","#f1c40f","#e74c3c","#34495e","#2ecc71","#3498db","#9a5a6","#9b59b6","#f1c40f","#e74c3c","#34495e","#2ecc71","#3498db","#95a5a6","#9b59b6","#f1c40","#e74c3c","#34495e","#2ecc71","#3498db","#95a5a6","#9b59b6","#f1c40f","#e74c3c","#34495e","#2ecc71","#3498db","#95a5a6","#9b59b6","#f1c40f","#e74c3c","#34495e","#2ecc71","#3498db","#955a6","#9b59b6","#f1c40f","#e74c3c","#34495e","#2ecc71","#3498db","#95a5a6","#9b59b6","#f1c40f,"#e74c3c","#34495e","#2ecc71","#3498db","#95a5a6","#9b59b6","#f1c40f","#e74c3c","#34495e"
          ],
          data: [74, 22, 77, 19, 72, 17, 55, 14, 64, 93, 99, 58, 6, 13, 31, 61, 19, 97, 25, 94, 50, 83, 3, 15, 54, 19, 60, 41, 37, 27, 51, 21, 36, 69, 80, 20, 64, 74, 79, 48, 66, 1, 94, 57, 5, 18, 83, 41, 64, 48]
        }]
      }
    });

Since its an canvas so styling is futile but you can look into how space can be saved one such thing would be to change width of color box legends as https://jsfiddle.net/5um78rbk/1/ or https://jsfiddle.net/5um78rbk/2/ or https://jsfiddle.net/5um78rbk/3/try some orientation or font to utilize max space of chart hope this helps — Vinod Louis, Apr 05 '17 at 11:33
@VinodLouis Thank you for answer but In our app we don't know how many data field we have, for example some chart has 10 data-field and some chart has more than 200 data-field, we are not fix that how many data-field we have. — Kaushik Makwana, Apr 05 '17 at 11:40

Vinod Louis · Accepted Answer · 2017-04-05T13:08:38.920

27

You can try one thing

Try to separate the legend into an different div. now you have full control of the div you can use custom placement and css of your own consider the following code :

 <div id="js-legend" class="chart-legend"></div>
 document.getElementById('js-legend').innerHTML = myChart.generateLegend();

For reference see this FIDDLE

For handling legend interactive you need to extend the callback function and manipulate like this :

$("#js-legend > ul > li").on("click",function(e){
        var index = $(this).index();
        $(this).toggleClass("strike")
        var ci = e.view.myChart;
        var curr = ci.data.datasets[0]._meta[0].data[index];
        curr.hidden = !curr.hidden
        ci.update();
})

For Legend in action see this FIDDLE

Explanation :

I binded chart to window so that event view can get it, and later by the index manipulated the data and updated runtime used few css tricks to illustrate the strike effect.

edited Apr 05 '17 at 13:08

answered Apr 05 '17 at 11:51

Vinod Louis

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:) @KaushikMakwana something like this should solve your problem https://jsfiddle.net/5um78rbk/5/ – Vinod Louis Apr 05 '17 at 11:56
You know what the legend are show as pain text, I want functional legend see my fiddle : https://jsfiddle.net/KDM1010/5um78rbk/ – Kaushik Makwana Apr 05 '17 at 12:03
when you click on legends you can compare your data with each other, In your solution there is plain legends it's not working – Kaushik Makwana Apr 05 '17 at 12:04
hmm let me see im sure there should be a way – Vinod Louis Apr 05 '17 at 12:26
@KaushikMakwana Fiddle updated for the same Enjoy coding :) – Vinod Louis Apr 05 '17 at 13:05
@Cherish you can see the solution in fiddle – Vinod Louis Apr 05 '17 at 13:05
@VinodLouis I am facing this problem since 2 weeks, I can not get it, but you solve it within 1 hour, You are brilliant, Thanks. – Cherish Apr 05 '17 at 13:11
1

this is made my day, it's easier to adjust legend style – Vany Diah P Dec 24 '18 at 22:50
hi @VinodLouis I tried the same thing but the Legend action is not triggered. i checked the console and i don't see `event.view`. could you address this to me? – Lucian Jun 27 '19 at 22:28
https://tppr.me/3B2mk this is all i get trying to console `e` and this is the code https://tppr.me/6owjn @VinodLouis – Lucian Jun 27 '19 at 22:34
@Lucian you are assigning chart as window.chart and trying to get value as e.view.mychart. moreover, I guess you are using multiple frames if you don't get e.view you can directly use window.chart also as e.view = window object only – Vinod Louis Jun 28 '19 at 03:19
a little extra explanation, index number of _meta object is depending on how many chart you use in one page :) – Abid Khairy Mar 30 '20 at 07:26

score 1 · Answer 2 · answered Oct 09 '18 at 11:53

I did not found any solution for this, but you can turn off legend if too many labels are to be shown (I did it in my project) - here is set to max 15 labels:

options : {
        responsive: true,
        maintainAspectRatio: false,
        layout: {
          padding: {
             left     : 0,
             right    : 0,
             top      : 0,
             bottom   : 0
          }
        },
        animation: {
          duration : 5000
        },
        legend: {
          display: this.chartValues.length <= 15,
        }
}

You can also make place for rendering charts bigger. Add this to your scss file:

.chartjs-render-monitor{
    height: 300px !important;
}

I hope it gonna help someone

hi @marcin you can render using highcharts, there is pagination available for legends, so no need to add scroll. Here is working example: http://jsfiddle.net/HpdwR/ — Vaibhav Gidde, Apr 28 '21 at 08:53

score 1 · Answer 3 · answered Jul 10 '21 at 18:21

As mentioned in other answers, a possible solution is externalize the legend as plain HTML div, on which you have full control.

Now, in ChartJS v3 the chart.generateLegend() function has been removed.

The maintainers, though, have published the so called htmlLegend plugin which externalises the legend, here is the link:

HTML Legend (External DIV) - ChartJS Docs

The plugin creates an interactive legend whose items can be clicked to show/hide datasets as in the original one.

NOTE: although having a scrollable legend might come in handy, having so many items in a legend could make the chart illegible and should make one consider representing data in a different way, perhaps by splitting data in more charts or introducing search functions

How to fix chart Legends width-height with overflow scroll in ChartJS

3 Answers3

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