How do I properly use graph.zoom?

[Brendan-DH]

I'm trying to use graph.zoom to focus on certain nodes when clicked. However, the spatial argument of zoom() seems to work quite strangely.

For example, if I do graph.zoom(1, {x:100,y:100}) then the view will not change whatsoever, compared to graph.zoom(1, { x: 0, y: 0 }). However, if I do graph.zoom(0.5, {x:100, y:100}), then the graph will zoom out to 0.5 and shift down and to the right compared to graph.zoom(0.5, { x: 0, y: 0 }) (as expected). Am I missing something? Why can't I move the viewport position with graph.zoom(1, {x:100,y:100})? And why does the scale of the spatial transformation seem to decrease if I do graph.zoom(2, {x:100,y:100})?