How to use JS library in WebView?

Question

JavaScript

There is a JS library for creating charts.
On a remote server, I created a rest api (sent parameters, received a picture in PNG).

There is an android application that creates json with parameters for the chart.

When a button is pressed in the application, a request with parameters is sent to the server. After receiving the response, the picture is inserted into the ImageView.

Everything is working. But very long - 10-15 seconds.

Maybe you can push the library into the application (for example, through WebView)? and do something like