creator searches for parent ScreenView

[pixelzoom]

I stumbled upon this while looking at https://github.com/phetsims/projectile-motion/issues/20.

Regarding this pattern in CoinTermCreatorNode, line 133:

        // find the parent screen if not already found by moving up the scene graph
        if ( !parentScreenView ) {
          var testNode = self;
          while ( testNode !== null ) {
            if ( testNode instanceof ScreenView ) {
              parentScreenView = testNode;
              break;
            }
            testNode = testNode.parents[ 0 ]; // move up the scene graph by one level
          }
          assert && assert( parentScreenView, 'unable to find parent screen view' );
        }

In https://github.com/phetsims/scenery-phet/issues/214#issuecomment-174014179 and in subsequent developer-meeting discussions, this approach was identified as undesirable. And we discussed better ways to do this. That was 1/22/2016. Why is this pattern still be using in this brand new sim?

[jbphet]

I think this is essentially a duplicate of https://github.com/phetsims/expression-exchange/issues/58, but I'll leave both open until the issue is addressed.

[jbphet]

I've implemented event forwarding for this, and it appears to be working well. There is one TODO for documentation remaining, but I'll track that in #58 and will make sure it gets addressed. @pixelzoom - do you want to review since you logged this issue? You're welcome to pass and wait until the code review if you prefer.

[jbphet]

Hang on - based on some examples that @samreid pointed me to, I think this can be simplified, so I'm assigning it back to me.

[pixelzoom]

@jbphet wrote:

I've implemented event forwarding for this, and it appears to be working well. ...

(1) @samreid recommended using the approach described in https://github.com/phetsims/scenery-phet/issues/214#issuecomment-296881631, and I thought we were all on the same page for that. What you've implemented doesn't seem to correspond to that.

(2) You are now calling private functions in MovableDragHandler (movableDragHandlerStart, movableDragHandlerEnd).

[pixelzoom]

Looks great, and matches the approach in phetsims/scenery-phet#214 (comment).

Closing.