AnimatedPanZoomListener doesn't keep the Node in view during drag in cases of event forwarding

[jessegreenberg]

Noticed in phetsims/equality-explorer#179.

The AnimatedPanZoomListener uses the Trail to the target of a down event to determine which Node should remain in view when dragging. That Trail is not the one we want to track when event is forwarded to another target with the creator pattern.

In general I don't think we should be using the Trail of the down event to accomplish this with the AnimatedPanZoomListener. I don't see any good way from Event or Pointer to retrieve the right Trail of the "grabbed" Node to keep it in view.

I am almost wondering about changing the behavior slightly to pan whenever the Pointer is near the edge of screen bounds and not make it based on whether the Node is out of view at all.

[Nancy-Salpepi]

Hey @jessegreenberg
Looking at your comment phetsims/equality-explorer#179 (comment), I would expect panning to work when moving an object that isn't coming from a toolbar. However, while testing phetsims/qa#738, the screen does not pan when I move a block.

(Using Mac OS 12.0.1 + chrome)

.

[jessegreenberg]

Ah, thanks @Nancy-Salpepi, Ill take a look at that case as well and see what is different. If I proceed with

I am almost wondering about changing the behavior slightly to pan whenever the Pointer is near the edge of screen bounds and not make it based on whether the Node is out of view at all.

I suspect it will fix all of these anyway.

[KatieWoe]

I also noticed that automatic panning may happen in phetsims/qa#738 when it isn't intended.

IMG_0084.MP4

[KatieWoe]

The above also happens from the bottom of the pool scrolling up.

[KatieWoe]

Noting this in phetsims/qa#751

[jessegreenberg]

This issue was replaced by #1558 which is complete. Closing this one as well.