Server-side image rendering for Google Charts

[Ian Webster]

Hi all,

I am writing to announce the release of an open-source project Google Charts Node that renders Google Charts as an image.

This may be useful in cases where you can't display charts in a browser client (e.g. email or reports), or if you want to save images but are using chart types that don't support getImageURI.

GoogleChartsNode can be used as either a node.js library or a web API.   It uses a headless Chromium browser to render images.  Here's an example usage as a library:

const GoogleChartsNode = require('google-charts-node');

// Define your chart drawing function

function drawChart() {

  // ...

  const chart = new google.visualization.BarChart(container);

  chart.draw(data, options);

}

// Render the chart to image

const image = await GoogleChartsNode.render(drawChart, {

  width: 400,

  height: 300,

});

Because it uses Google's Javascript libraries to render, results are the same as regular Javascript Google Charts:

For those not using Javascript, you can host the project as a web server (container support pending if there's interest) and invoke it from your application.  Or, you can use the hosted version, which is running on Google Cloud infrastructure.

Endpoint (GET/POST): https://quickchart.io/google-charts/render

Parameters:

• code: Javascript contents of drawChart (required)
  
• packages: Comma-separated list of Google Visualization packages to load (defaults to "corechart")
• width: Width of chart canvas in pixels
• height: Height of chart canvas in pixels
• mapsApiKey:  Maps key for geochart and maps

For more complex charts, I recommend POSTing your parameters as JSON.

Example chart image URL: https://quickchart.io/google-charts/render?packages=timeline&code=...

Documentation: https://quickchart.io/documentation/google-charts-image-server/

Feedback and improvements on this open-source project are welcome at the google-charts-node Github.

As a disclaimer, I'm a former Googler but this offering is open-source and not affiliated with Google.

Ian