Allow Simultaneous User Interaction View State Transitions

Target Use case

Simultaneously being able to pan and zoom (for example) would result in a smoother and improved UX for navigating views.

Proposed feature

Currently, TRANSITION_EVENTS are BREAK, SNAP_TO_END, and IGNORE, which only allow for sequential view state transitions, i.e. panning will cancel/ignore zoom transitions, and zooming will cancel/ignore panning transitions.

Possibly, an implementation could be keeping sequential view state transitions, but to allow for a single view state transition to simultaneously represent the combined effects of user inputs (?). This way the user could simultaneously pan and zoom, but if a new view state was set with a FlyToInterpolator for example, then the previous user input transitions would be cancelled.

With this feature, (enabled) inertia from panning would not be interrupted by a zoom event, and (enabled) smooth-zooming from a zoom would not be interrupted by panning.

To Do List

• Add label and assign to milestone
• Coding
• Doc update
• What’s new update
• Test

The issue names no files or tests; start with the view-state transitions documentation and the TRANSITION_EVENTS and FlyToInterpolator entry points mentioned here. Define how simultaneous pan and zoom should combine while preserving cancellation when a FlyToInterpolator transition starts. Done should include coding, tests, documentation, and a What's New update.