Book Image

Learn Chart.js

By : Helder da Rocha
Book Image

Learn Chart.js

By: Helder da Rocha

Overview of this book

Chart.js is a free, open-source data visualization library, maintained by an active community of developers in GitHub, where it rates as the second most popular data visualization library. If you want to quickly create responsive Web-based data visualizations for the Web, Chart.js is a great choice. This book guides the reader through dozens of practical examples, complete with code you can run and modify as you wish. It is a practical hands-on introduction to Chart.js. If you have basic knowledge of HTML, CSS and JavaScript you can learn to create beautiful interactive Web Canvas-based visualizations for your data using Chart.js. This book will help you set up Chart.js in a Web page and show how to create each one of the eight Chart.js chart types. You will also learn how to configure most properties that override Chart’s default styles and behaviors. Practical applications of Chart.js are exemplified using real data files obtained from public data portals. You will learn how to load, parse, filter and select the data you wish to display from those files. You will also learn how to create visualizations that reveal patterns in the data. This book is based on Chart.js version 2.7.3 and ES2015 JavaScript. By the end of the book, you will be able to create beautiful, efficient and interactive data visualizations for the Web using Chart.js.
Table of Contents (14 chapters)
Title Page
Copyright and Credits
About Packt

Displaying multiple charts

Many times, you need to display more than one chart in a page to present different sets of data, or different views of the same data using different chart types. You may also wish to draw multiple charts over the same axes, so they can be compared. Another possibility is to use Canvas to draw over or under a chart and add context or additional data. All these scenarios are possible in Chart.js, but they require different strategies.

Rendering many charts on one page

You can render several different charts on the same page by simply drawing a separate Canvas for each one.

The following example displays four charts on one page that share the same data. First, we need to set up the canvases using HTML and CSS:

<html lang="en">
     <script src=".../Chart.min.js"></script>
         .container {
             width: 98%;
             height: 80vh;
             position: absolute;
         .top {