I have a chart which is showing information from a data-tree. Root is a big circle where the user can see children as smaller circles inside it. based on the space available, the user may see more than one level at a time. The user needs to have a intuitive way of diving in and out. Constraints are
- prefer not to have text buttons.
- It should only work with taps. not less controllable pitch in-out gestures
- prefer not to have a menu or global button.
- each circle also has a title, that displays details on a separate pane when clicked. I should avoid having accidental dive-in when user just wants to see the details.
zooming is not difficult to solve. when tapped inside a circle, but outside text area, I dive in.