Open source standalone application to generate charts generically.
You just need to send a ajax request with well-formatted json (powered by http://www.chartjs.org/docs) to this application url and show the result.
When you access the root application url, you can see a usage example for all charts available.
git clone https://github.com/rihjsantos/chart-api.git
cd chart-api
composer install
php artisan serve
access http://localhost:8000/ and see the usage