function applyZoom
observer.ts:255
A zoom, as a multiplier on distance.
factor above 1 retreats. Wheel notches and pinch gestures both arrive here:
a pinch is already a ratio, and a notch becomes one through ZOOM_PER_NOTCH.
- stateObserverState
- Undocumented
- factornumber
- Undocumented
- radiusnumber
- Undocumented
ReturnsObserverState