CODEWITHSUNDEEP
chart.jschart.js2
Bryan Lewis
Bryan Lewis

Reputation: 5977

Chart.js - Increase spacing between legend and chart

I have a bar chart where I have drawn 3 vertical lines, each with it's own label at the top. I would like those labels to be above the top of the y-axis (above the 30% line in the example) but below the legend. I can't figure out how to increase the space between the top legend and the chart such that I can have my vertical line labels (15, 24 & 33) be off of the chart itself but below the legend. Any ideas?

Example Chart

Upvotes: 61

Views: 102947

Answers (16)

Arsen Babajanyan
Arsen Babajanyan

Reputation: 123

For react-chartjs-2 with typescript

interface ExtendedLegendElement extends LegendElement<'bar'> {
    fit: () => void
}

const increaseLegendSpacing: Plugin<'bar'> = {
    id: 'increase-legend-spacing',
    beforeInit(chart) {
        const legend = chart.legend as ExtendedLegendElement | null
        if (legend && legend.fit) {
            const originalFit = legend.fit
            legend.fit = function fit() {
                originalFit.call(this)
                this.height += 20
            }
        }
    },
}

Upvotes: 0

Pepe Alvarez
Pepe Alvarez

Reputation: 1624

I know this is not what OP really wants but at least for newer versions, and the one I used - 4.0.1 - there is no way to increase the margin between the legend box and the chart, that I have been able to find at least, so this is a workaround. In order to avoid this problem:

enter image description here

I had to change the position of the legend box below the chart with these option configurations:

options = {
    layout: {
        padding: 30
    },
    parsing: {
        key: 'nested.value'
    },
    plugins: {
        datalabels: {
            color: '#36A2EB'
        },
        tooltip: {
            enabled: true
        },
        legend: {
            position: 'bottom',
            align: 'center',
            labels: {
                padding: 20,
            }
        }
    }
};

Note: To add the values at the top of the bars I had to add the npm package chartjs-plugin-datalabels with the following features inside your datasets config:

datasets: [
    {
        label: "Ejercido",
        data: source.map( s => s.ejercidoTotal),
        datalabels: {
        anchor: 'end',
        clamp: true,//this makes one datalabel not visible if it crashed with other one
        display: 'auto',
        align: 'top',
        color: '#333333',
        formatter
        }
    },
    ...
]

With this as the result:

enter image description here

Upvotes: 1

Utku Aky&#252;z
Utku Aky&#252;z

Reputation: 1

I had a similar issue with bar charts. In the end I found a workaround instead of AfterFit method to solve the issue.

My original chart looks like this original chart

And after I added the following options to my chart,

options: {
           scales: {
                y: {
                  beginAtZero: true,
                  grace: '5%',
                }
              },
            },

Final image is final charts. This workaround worked for me. Grace is adding kind of padding at the top of the chart. Source: https://www.youtube.com/watch?app=desktop&v=3Pss5GvlPd0&ab_channel=ChartJS

Upvotes: 0

tuan vu
tuan vu

Reputation: 353

If using react-chartjs-2 and want to avoid using a custom plugin, then a hacky solution is to use a fake x-axis with an empty label.

<Chart options={{
  scales: {
    x: {
      // Your real x-axis options
    },
    xTopPadding: {
      // Fake x-axis for padding
      position: 'top',
      labels: [''],
      grid: {
        drawOnChartArea: false,
        drawTicks: true,
        ticksWidth: 0,
        ticksLength: 0, // Increase ticksLength to increase the "padding"
      },
    }
  }
}} />

Upvotes: 2

Glogo
Glogo

Reputation: 2884

If anyone is wondering why the afterFit solution is not working in Chart.js 3.3.0 it is because the afterFit function was removed from the legend plugin.

If you want to make this work anyway by taking advantage of the fit function, you can try this hacky solution / workaround:

const plugin = {
  beforeInit(chart) {
    // Get a reference to the original fit function
    const originalFit = chart.legend.fit;

    // Override the fit function
    chart.legend.fit = function fit() {
      // Call the original function and bind scope in order to use `this` correctly inside it
      originalFit.bind(chart.legend)();
      // Change the height as suggested in other answers
      this.height += 15;
    }
  }
}

I know that this is not an ideal solution, but until we have native support for this legend padding, I'm afraid this is as good as we can do right now.

Upvotes: 32

Nidhi Shah
Nidhi Shah

Reputation: 2476

If you are using react-chartjs-2 library to show chart in a React app. You can use the below solution:

const plugin = {
  beforeInit: function (chart) {
    // Get reference to the original fit function
    const originalFit = chart.legend.fit

    // Override the fit function
    chart.legend.fit = function fit() {
      // Bind scope in order to use `this` correctly inside it
      originalFit.bind(chart.legend)()
      this.height += 20 // Change the height
    }
  }
}

export const ReactChart2Example = (props) => {
  const { data = [] } = props;

  return (
    <div>
      <Chart plugins={[plugin]} type ="bar" data={data}/>
    </div>
  );
};

We have to pass plugins prop separately in React js Chart component and not inside options.

Reference: https://github.com/chartjs/Chart.js/issues/10388#issuecomment-1217363379

Upvotes: 2

eko
eko

Reputation: 40647

For ng2-charts@^3.1.0, following this answer works with an addition:

this.options.labels.padding = 40;
//this.height += 15;

or the title.padding config (this'll create an invisible title under the graph so it's a bit hacky):

    plugins: {
      legend: {
        display: true,
        position: 'bottom',
        title: {
          display: true,
          padding: 10,
        },

Stackblitz

Upvotes: 2

Harsh Boricha
Harsh Boricha

Reputation: 133

If you want to apply padding below legend for some charts only in your app:

ChartJS >= 2.1.0

Note: make sure to add this in plugins and not inside options.plugins.

Chart.plugins.register({
  id: 'paddingBelowLegends',
  beforeInit: function(chart, options) {
    chart.legend.afterFit = function() {
      this.height = this.height + 50;
    };
  }
});

// ----------------------------------
// disable the plugin only for charts
// where you DO NOT WANT the padding
// ----------------------------------

// for raw ChartJS use:
var chart = new Chart(ctx, {
  config: {
    plugins: {
      paddingBelowLegends: false
    }
  }
});

For React Users using react-chartjs-2:

import { Line } from "react-chartjs-2";
import { Chart as ChartJS, CategoryScale, LinearScale, PointElement, LineElement, Title, Tooltip, Legend } from "chart.js";
  ChartJS.register(CategoryScale, LinearScale, PointElement, LineElement, Title, Tooltip, Legend);
<Line
        data={{
          datasets: trendsData?.map((trend, idx) => ({
            type: "line",
            label: trend.domainName,
            data: trend.domainTrends.map(d => d.value),
            backgroundColor: getDomainColor(idx).backgroundColor,
            borderColor: getDomainColor(idx).color,
            pointRadius: 0,
            tension: 0.3
          })),
          labels: trendsData?.[0]?.domainTrends.map(d => d.date)
        }}
        options={{
          plugins: {
            legend: {
              display: true,
              align: "start",
              labels: {
                font: { size: 14 }
              }
            }
          }
        }}
        plugins={[
          {
            id: "increase-legend-spacing",
            beforeInit(chart) {
              // Get reference to the original fit function
              const originalFit = (chart.legend as any).fit;
              // Override the fit function
              (chart.legend as any).fit = function fit() {
                // Call original function and bind scope in order to use `this` correctly inside it
                originalFit.bind(chart.legend)();
                this.height += 20;
              };
            }
          }
        ]}
      />

Upvotes: 3

PArt
PArt

Reputation: 23

After searching the chart.js file I found out that the height of the labels bar is defined there in

height = this._fitRows(titleHeight, fontSize, boxWidth, itemHeight)

OR

this.height = Math.min(height, options.maxHeight || this.maxHeight)

in the fit() function

fit() {
const {options, ctx} = this;
if (!options.display) {
  this.width = this.height = 0;
  return;
}
const labelOpts = options.labels;
const labelFont = toFont(labelOpts.font);
const fontSize = labelFont.size;
const titleHeight = this._computeTitleHeight();
const {boxWidth, itemHeight} = getBoxSize(labelOpts, fontSize);
let width, height;
ctx.font = labelFont.string;
if (this.isHorizontal()) {
  width = this.maxWidth;
  height = this._fitRows(titleHeight, fontSize, boxWidth, itemHeight);
} else {
  height = this.maxHeight;
  width = this._fitCols(titleHeight, fontSize, boxWidth, itemHeight);
}
this.width = Math.min(width, options.maxWidth || this.maxWidth);
this.height = Math.min(height, options.maxHeight || this.maxHeight) + 40;}

And I changed it to +40 as shown above. and it worked fine for me so I wanted to share.

Upvotes: 1

Kirit Bhatt
Kirit Bhatt

Reputation: 1

You can use layout property under options. This helped me:

   layout: {
        padding: {
            left: 50,
            right: 130,
            top: 0,
            bottom: 0
        }
    }

Upvotes: -10

Jaison James
Jaison James

Reputation: 4552

I have tried the above approaches on my react(react-chartjs-2) project but no luck. Here I have one different approach like creating custom legends outside the chart. so you can get more control over it

  1. Hide default legend
  2. Get legend object using any ref method.
  3. Loop and make a custom legend using html and css.
  4. Sample codesanbox

I am aware that OP is not about reactjs component, but as it is a common issue it will help someone.

Orginal reference

.

Upvotes: 1

Itsca
Itsca

Reputation: 394

I'm using react-chartjs-2 (but this is just a port and uses the same configurations object) and I was able to achieve that by changing the labels configuration nested on legend configuration:

chartOptions = {
  legend: {
    labels: {
      padding: 50 -> this one.
    }
  },

You can check the property description here: https://www.chartjs.org/docs/latest/configuration/legend.html

Hope it helps.

Upvotes: 7

Sahil Ralkar
Sahil Ralkar

Reputation: 2424

This helped me after 2 days of research.

Chart.Legend.prototype.afterFit = function() {
    this.height = this.height + 50;
};

update this in module.ts file

Upvotes: 8

Maxime Pacary
Maxime Pacary

Reputation: 23001

If you want to apply padding below legend for some charts only in your app:

ChartJS >= 2.1.0

Chart.plugins.register({
  id: 'paddingBelowLegends',
  beforeInit: function(chart, options) {
    chart.legend.afterFit = function() {
      this.height = this.height + 50;
    };
  }
});

// ----------------------------------
// disable the plugin only for charts
// where you DO NOT WANT the padding
// ----------------------------------

// for raw ChartJS use:
var chart = new Chart(ctx, {
  config: {
    plugins: {
      paddingBelowLegends: false
    }
  }
});

// for angular-chartjs:
$scope.myChart.options.plugins = { paddingBelowLegends: false }
// then in template:
// <canvas class="chart ..." chart-options="myChart.options" ... />

ChartJS >= 2.5.0

Specific plugins for each chart are supported, it should be possible to do:

var chart = new Chart(ctx, {
  plugins: [{
    beforeInit: function(chart, options) {
      chart.legend.afterFit = function() {
        this.height = this.height + 50;
      };
    }
  }]
});

See ChartJS documentation + inspired by this other answer

Upvotes: 37

Dorian Maliszewski
Dorian Maliszewski

Reputation: 891

If you want do increase spacing in all charts you can put this code before creating :

Chart.Legend.prototype.afterFit = function() {
    this.height = this.height + 50;
};

Of course, I don't try but i think you can change it (or copy the original Chart object before, to keep the original padding).

Bye,

Upvotes: 46

jordanwillis
jordanwillis

Reputation: 10705

Unfortunately, since there is no config option to handle this the only way you can achieve the desired result is to extend Chart.Legend and implement the afterFit() callback.

Here is a quick codepen showing how to do just that. To change the spacing, just change the value in line 9 (currently set to 50). Also, this of course only works with the legend at the top. Hopefully, the example is clear enough for you to modify in case you want to move your legend elsewhere.

Upvotes: 20

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