Unfortunately PD4ML does not support JavaScript and Canvas – so most probably that is the problem reason.

On the other hand if you generate the chart in a regular browser, extract the image as a base64-encoded data URL and pass the image to PD4ML to be converted to PDF – the trick may work.

In the case it would help if you send us a typical data URL, obtained with canvas.toDataURL(). We’ll check what could be done.