Yes, it is old, but the answer seems to be this valid. chartjs is not able to do localization (and apparently there are no plans either), as there are too many localizations. But as shown above they have implemented callback functions. Look at them as being kind of “webhooks” allowing you to inject your own JS routines. In such a callback you can for instance convert the number in the label to string(locale). I made this work on my own chartjs implementation.
But the issue is that we (Xojo users) don’t have direct access to chart.js. We only have this OverrideOptions event which does what its name implies. You can override options but I have no idea how we could be able to implement a callback in this event. Unfortunately, localization is important.Every customer will tell you “Perfectly done Jeannot, but now replace this dot with a comma please, or did you not pay attention at school” ;-). Now tell your customer that changing a dot to a comma is not possible and you are instantly in a big debate …