phantom-chartjs

phantom-chartjs is a CommonJS module for rendering Chart.js charts to images on the server. Rendering is accomplished using PhantomJS. In order
to keep response times low, PhantomJS is spanwed as a server process.

Installation

Install using npm:

``
$ npm install phantom-chartjs --save
`

TypeScript

TypeScript definitions are included in the package, so typings are automatically provided to TypeScript without any additional work.

Usage

#### Create a renderer

In your server, create a renderer. This starts a PhantomJS server on the default port of 8083. If a different port is desired, pass it as on option to createChartRenderer.
The renderer should be created once and used throughout your server.

`javascript
import {createChartRenderer} from "phantom-chartjs";

createChartRenderer({ port: 8080 }, (err, renderer) => {
if (err) throw err;

...
});
`

#### Define your chart configuration

See the Chart.js documentation for more information.

`javascript
var config = {
chart: {
type: 'bar',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
backgroundColor: [
'rgba(255, 99, 132, 0.2)',
'rgba(54, 162, 235, 0.2)',
'rgba(255, 206, 86, 0.2)',
'rgba(75, 192, 192, 0.2)',
'rgba(153, 102, 255, 0.2)',
'rgba(255, 159, 64, 0.2)'
],
borderColor: [
'rgba(255,99,132,1)',
'rgba(54, 162, 235, 1)',
'rgba(255, 206, 86, 1)',
'rgba(75, 192, 192, 1)',
'rgba(153, 102, 255, 1)',
'rgba(255, 159, 64, 1)'
],
borderWidth: 1
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
}
}
}
};
`

#### Render to a Buffer

In order to render a chart to an image Buffer, call renderBuffer. By default the PNG format is used.

`javascript
renderer.renderBuffer(config, function (err, buffer) {
if (err) throw err;

// the buffer now contains a Buffer with the rendered PNG
...
});
`

#### Render to Base 64

You can also render to base 64 encoding using renderBase64.

`javascript
renderer.renderBase64(config, function (err, data) {
if (err) throw err;

// the data now contains a base 64 encoding string with the rendered PNG
...
});
`

#### Close the renderer

Make sure to close the renderer when your server exits; otherwise, the PhantomJS server process may not exit.

`javascript
process.on("exit", () => {

renderer.close();
});
``