quickchart-java

A Java client for the QuickChart.io chart API.

Installation

Add QuickChart to your project (Java 6+). The io.quickchart package is available on Maven Central

Maven:

<dependency>
    <groupId>io.quickchart</groupId>
    <artifactId>QuickChart</artifactId>
</dependency>

Gradle:

dependencies {
    implementation 'io.quickchart:Quickchart:VERSION'
}

Usage

This library provides a QuickChart namespace containing a Chart class. Import and instantiate it. Then set properties on it and specify a Chart.js config:

import io.quickchart.QuickChart;

// ...

QuickChart chart = new QuickChart();
chart.setWidth(500);
chart.setHeight(300);
chart.setConfig("{"
    + "    type: 'bar',"
    + "    data: {"
    + "        labels: ['Q1', 'Q2', 'Q3', 'Q4'],"
    + "        datasets: [{"
    + "            label: 'Users',"
    + "            data: [50, 60, 70, 180]"
    + "        }]"
    + "    }"
    + "}"
);

For more details on configuring your chart, reference the QuickChart documentation.

Use getUrl() on your QuickChart object to get the encoded URL that renders your chart:

System.out.println(qc.getUrl());
// https://quickchart.io/chart?c=%7B%22chart%22%3A+%7B%22type%22%3A+%22bar%22%2C+%22data%22%3A+%7B%22labels%22%3A+%5B%22Hello+world%22%2C+%22Test%22%5D%2C+%22datasets%22%3A+%5B%7B%22label%22%3A+%22Foo%22%2C+%22data%22%3A+%5B1%2C+2%5D%7D%5D%7D%7D%7D&w=600&h=300&bkg=%23ffffff&devicePixelRatio=2.0&f=png

If you have a long or complicated chart, use getShortUrl() to get a fixed-length URL using the quickchart.io web service (note that these URLs only persist for a short time unless you have a subscription):

System.out.println(qc.getShortUrl());
// https://quickchart.io/chart/render/f-a1d3e804-dfea-442c-88b0-9801b9808401

The URLs will render an image of a chart:

See io.quickchart.examples to see other example usage.

---

Customizing your chart

You can set the following properties:

setConfig(String)

The Chart.js chart configuration.

setWidth(Integer)

Width of the chart image in pixels. Defaults to 500

setHeight(Integer)

Height of the chart image in pixels. Defaults to 300

setBackgroundColor(String)

The background color of the chart. Any valid HTML color works. Defaults to #ffffff (white). Also takes rgb, rgba, and hsl values.

setDevicePixelRatio(Double)

The device pixel ratio of the chart. This will multiply the number of pixels by the value. This is usually used for retina displays. Defaults to 1.0.

setVersion(String)

The Chart.js version of the chart. See QuickChart documentation for default.

setKey(String)

API key (not required)

---

Creating chart URLs

There are a few ways to get a URL for your chart object.

getUrl(): String

Returns a URL that will display the chart image when loaded.

getShortUrl(): String

Uses the quickchart.io web service to create a fixed-length chart URL that displays the chart image. Returns a URL such as https://quickchart.io/chart/render/f-a1d3e804-dfea-442c-88b0-9801b9808401.

Note that short URLs expire after a few days for users of the free service. You can subscribe to keep them around longer.

---

Other methods

toFile(String path)

Write your chart to file.

toByteArray(): byte[]

Returns an array of bytes representing your image.

toBase64Url(): String

Returns a string suitable for display as a base 64 url beginning with data:image/png;base64,

More examples

Check out the io.quickchart.examples to see other usage.