Hi @Alexander Eder 

If your graph is wrapped inside a container, you can zoom in/out of that container by applying javascript. You would have a ZoomIn() and ZoomOut() functions triggered on the onclick of each of your buttons, and inside you would place a javascript node with the following:

ZoomIn():

var el = document.getElementById(container.Id);

var width = el.clientWidth;

el.style.width = width + 100 + "px";

ZoomOut():

var el = document.getElementById(container.Id);

var width = el.clientWidth;

el.style.width = width - 100 + "px";

where container.Id is the Id of your container you want to zoom.

Let me know if this helps!

Kind regards,

Paulo