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Jakub Juszczak
Jakub Juszczak

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Creating stunning charts with Vue.js and Chart.js

#vue #chartjs

Dive into the options of chart.js to create stunning charts.

Interactive charts can provide a cool way to visualize your data.
However most out of the box solutions are not as beautiful as they could be, with default options.

I will show you how to customize your chart.js options to make some cool charts!

âš¡ Quick Start

What we will use:

We use vue-cli to create a basic structure. So I hope you got it installed already. And we use vue-chartjs as a wrapper for chart.js.

vue init webpack awesome-charts
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Then we go into our project folder and install our dependencies.

cd awesome-charts && yarn install
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And we add vue-chartjs :

yarn add vue-chartjs -S
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Our first chart

So, let's create our first line chart.

touch src/components/LineChart.js && subl .
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Now we need to import the Line BaseChart from vue-chartjs and create our component.

In the mount() function we need to call the renderChart() method with our data and options.

import {Line} from 'vue-chartjs'

export default Line.extend({
  mounted () {

    this.renderChart({
      labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
      datasets: [
        {
          label: 'Data One',
          backgroundColor: '#FC2525',
          data: [40, 39, 10, 40, 39, 80, 40]
        },{
          label: 'Data Two',
          backgroundColor: '#05CBE1',
          data: [60, 55, 32, 10, 2, 12, 53]
        }
      ]
    }, {responsive: true, maintainAspectRatio: false})

  }
})
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We pass in a basic chart.js data object with some sample data and in the option parameter, we pass responsive: true. So the chart will grow based on our outer container.

☝ We can call the method renderChart() because we extended the BaseChart, were this method and some props are defined.

Mount & Test it

Now we delete the Hello.vue component from our App.vue and import our chart.

<template>
  <div id="app">
    <div class="container">
      <div class="Chart__list">
        <div class="Chart">
          <h2>Linechart</h2>
          <line-example></line-example>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import LineExample from './components/LineChart.js'
export default {
  name: 'app',
  components: {
    LineExample
  }
}
</script>

<style>
#app {
  font-family: 'Avenir', Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
  color: #2c3e50;
  margin-top: 60px;
}
.container {
  max-width: 800px;
  margin:  0 auto;
}
</style>
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And after we run the dev script in our terminal, we should see our chart.

yarn run dev
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💄 Make me beautiful

Okay, now it is time for some beautification 💅. There are a few cool tricks in chart.js. We can pass a color hex value to backgroundColor; But we can also pass a rgba() value. So we can make our color transparent.
And as chart.js is using html canvas to draw, we can utilize createLinearGradient().

This is where the fun starts. 🎢 But to use it we need the canvas object. But this is not a big deal, as vue-chartjs holds a reference to it. We can access it over this.$refs.canvas

So in our LineChart.js we create two variables to store a gradient. Because we have to datasets.

Then we create two gradients:

this.gradient = this.$refs.canvas
 .getContext('2d')
 .createLinearGradient(0, 0, 0, 450)
this.gradient2 = this.$refs.canvas
 .getContext('2d')
 .createLinearGradient(0, 0, 0, 450)
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There is another cool function we can use: addColorStop()

We create three colorStops for each gradient. For 0%, 50% and 100%.

this.gradient.addColorStop(0, 'rgba(255, 0,0, 0.5)')
this.gradient.addColorStop(0.5, 'rgba(255, 0, 0, 0.25)');
this.gradient.addColorStop(1, 'rgba(255, 0, 0, 0)');

this.gradient2.addColorStop(0, 'rgba(0, 231, 255, 0.9)')
this.gradient2.addColorStop(0.5, 'rgba(0, 231, 255, 0.25)');
this.gradient2.addColorStop(1, 'rgba(0, 231, 255, 0)');
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Now we can pass this.gradient to backgroundColor. And we have a very nice gradient. To get a nicer effect we also set the borderColor to the individual color with an alpha of 1. (or we use the hex value) And set the borderWidth to 1 and last but not least the pointColor.

borderColor: '#FC2525', 
pointBackgroundColor: 'white', 
borderWidth: 1, 
pointBorderColor: 'white',
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import {Line} from 'vue-chartjs'

export default Line.extend({
  data () {
    return {
      gradient: null,
      gradient2: null
    }
  },
  mounted () {
    this.gradient = this.$refs.canvas.getContext('2d').createLinearGradient(0, 0, 0, 450)
    this.gradient2 = this.$refs.canvas.getContext('2d').createLinearGradient(0, 0, 0, 450)

    this.gradient.addColorStop(0, 'rgba(255, 0,0, 0.5)')
    this.gradient.addColorStop(0.5, 'rgba(255, 0, 0, 0.25)');
    this.gradient.addColorStop(1, 'rgba(255, 0, 0, 0)');

    this.gradient2.addColorStop(0, 'rgba(0, 231, 255, 0.9)')
    this.gradient2.addColorStop(0.5, 'rgba(0, 231, 255, 0.25)');
    this.gradient2.addColorStop(1, 'rgba(0, 231, 255, 0)');


    this.renderChart({
      labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
      datasets: [
        {
          label: 'Data One',
          borderColor: '#FC2525',
          pointBackgroundColor: 'white',
          borderWidth: 1,
          pointBorderColor: 'white',
          backgroundColor: this.gradient,
          data: [40, 39, 10, 40, 39, 80, 40]
        },{
          label: 'Data Two',
          borderColor: '#05CBE1',
          pointBackgroundColor: 'white',
          pointBorderColor: 'white',
          borderWidth: 1,
          backgroundColor: this.gradient2,
          data: [60, 55, 32, 10, 2, 12, 53]
        }
      ]
    }, {responsive: true, maintainAspectRatio: false})

  }
})
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Presentation

Last step is to add some styling to the container in our App.vue

.Chart {
  background: #212733;
  border-radius: 15px;
  box-shadow: 0px 2px 15px rgba(25, 25, 25, 0.27);
  margin:  25px 0;
}

.Chart h2 {
  margin-top: 0;
  padding: 15px 0;
  color:  rgba(255, 0,0, 0.5);
  border-bottom: 1px solid #323d54;
}
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👏 Final Result

Top comments (6)

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l_alcubo profile image
Luis •

Hello friends I have a problem with the code, it works perfect, the problem is that once I paint everything, I return and sending other values paints them with the current value, perfect, but if I place the cursor on the line it overlaps with The old value

codepen.io/lalcubo/pen/VWrJwG

sorry for my english and for my code, but i dont know use good the site codepen.io for work the code please download the code and create the file .html and file .js and the library vue and vue-chart thanks

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apertureless profile image
Jakub Juszczak •

Hey,

for a working codepen, you need to include vue-chartjs from the cdn

https://cdnjs.cloudflare.com/ajax/libs/vue-chartjs/2.6.5/vue-chartjs.full.min.js

To work with "live" data, you will need to inlcude the reactiveProp Mixin or reactiveData Mixin, depending on if you're passing your chartdata as a prop to your component or you're using a local data model.

Check out the docs: vue-chartjs.org/#/home?id=reactive...

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l_alcubo profile image
Luis •

I got my code to work finally on the website codepen: codepen.io/lalcubo/pen/VWrJwG

My problem its the following:
When i press the button it graphs correctly, and you can see it draws a dot (caption) with it's value.
If you press the button again, it graphs perfectly again with a random value,
if you mouseover the new value(dot) show the current value, but if you mouseover the cursor over the previous value(dot) it will show the old value(dot) overlaping it.
I need to show only the current value, not the previous ones.

thanks

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plavookac profile image
Jelena Jovanovic •

Great post! I recently published also Chart.js tutorial, on how to create gradient line charts. Keep up the good work! :)

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bhaskar_vk profile image
Bhaskar Karambelkar •

Nice and thanks!

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samarmustafa profile image
Samar Mustafa •

Awesome

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