[Feature] Know current zoom rate in viewport #16920
Description
What problem does this feature solve?
This is an UX issue regarding the graph chart.
I have built a small context menu that pops up when the user clicks on a node to allow him to add new nodes and links.
When the new nodes or links are added to the chart options, the current zoom rate is not kept.
If the graph is huge and the user has to zoom to find the place he wants to edit, this is very annoying to have to zoom again each time.
I read through the docs but didn't find a way to know the current zoom rate so it could be applied to the new options.
What does the proposed API look like?
Emit an event whenever the viewport is zoomed in or out, or provide an option to retain automatically the current zoom rate even when the data change.