From 1fc908b8bdb8366476e365c3d9651dd9f43b0223 Mon Sep 17 00:00:00 2001
From: samreid <reids@colorado.edu>
Date: Fri, 15 Dec 2017 12:27:23 -0700
Subject: [PATCH] Converted to use PhetioObject, see
 https://github.com/phetsims/tandem/issues/46

---
 .../model/ElectricPotentialLine.js            | 32 ++++++++-----------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/js/charges-and-fields/model/ElectricPotentialLine.js b/js/charges-and-fields/model/ElectricPotentialLine.js
index a377ae1c..fc703f86 100644
--- a/js/charges-and-fields/model/ElectricPotentialLine.js
+++ b/js/charges-and-fields/model/ElectricPotentialLine.js
@@ -12,6 +12,7 @@ define( function( require ) {
   var chargesAndFields = require( 'CHARGES_AND_FIELDS/chargesAndFields' );
   var dot = require( 'DOT/dot' );
   var inherit = require( 'PHET_CORE/inherit' );
+  var PhetioObject = require( 'TANDEM/PhetioObject' );
   var Shape = require( 'KITE/Shape' );
   var Vector2 = require( 'DOT/Vector2' );
 
@@ -44,8 +45,6 @@ define( function( require ) {
                                   isPlayAreaChargedProperty,
                                   tandem ) {
 
-    var self = this;
-
     this.getElectricPotential = getElectricPotential; // @private static
     this.getElectricField = getElectricField; // @private static
     this.chargedParticles = chargedParticles; // @private static
@@ -62,20 +61,15 @@ define( function( require ) {
     // @public (read-only) - used to identify tandems for the corresponding views
     this.electricPotentialLineTandem = tandem;
 
-    tandem.addInstance( this, { phetioType: ElectricPotentialLineIO } );
-
-    this.disposeElectricPotentialLine = function() {
-      tandem.removeInstance( self );
-    };
+    PhetioObject.call( this, {
+      tandem: tandem,
+      phetioType: ElectricPotentialLineIO
+    } );
   }
 
   chargesAndFields.register( 'ElectricPotentialLine', ElectricPotentialLine );
 
-  return inherit( Object, ElectricPotentialLine, {
-
-    dispose: function() {
-      this.disposeElectricPotentialLine();
-    },
+  return inherit( PhetioObject, ElectricPotentialLine, {
 
     /**
      * Given an (initial) position, find a position with the targeted electric potential within a distance 'deltaDistance'
@@ -142,8 +136,8 @@ define( function( require ) {
       var k4Vector = this.getElectricField( position.plus( k3Vector.timesScalar( deltaDistance ) ) ).normalize().rotate( Math.PI / 2 ); // {Vector2} normalized Vector along electricPotential
       var deltaDisplacement =
         {
-          x: deltaDistance * (k1Vector.x + 2 * k2Vector.x + 2 * k3Vector.x + k4Vector.x) / 6,
-          y: deltaDistance * (k1Vector.y + 2 * k2Vector.y + 2 * k3Vector.y + k4Vector.y) / 6
+          x: deltaDistance * ( k1Vector.x + 2 * k2Vector.x + 2 * k3Vector.x + k4Vector.x ) / 6,
+          y: deltaDistance * ( k1Vector.y + 2 * k2Vector.y + 2 * k3Vector.y + k4Vector.y ) / 6
         };
       return position.plus( deltaDisplacement ); // {Vector2} finalPosition
     },
@@ -192,8 +186,8 @@ define( function( require ) {
       var clockwiseEpsilonDistance = MIN_EPSILON_DISTANCE;
       var counterClockwiseEpsilonDistance = -clockwiseEpsilonDistance;
 
-      while ( (stepCounter < MAX_STEPS ) && !this.isLineClosed &&
-              (this.isEquipotentialLineTerminatingInsideBounds || (stepCounter < MIN_STEPS ) ) ) {
+      while ( ( stepCounter < MAX_STEPS ) && !this.isLineClosed &&
+              ( this.isEquipotentialLineTerminatingInsideBounds || ( stepCounter < MIN_STEPS ) ) ) {
 
         nextClockwisePosition = this.getNextPositionAlongEquipotentialWithElectricPotential(
           currentClockwisePosition,
@@ -339,7 +333,7 @@ define( function( require ) {
 
         // shorten the epsilon distance in tight turns, longer steps in straighter stretch
         // 360 implies that a perfect circle could be generated by 360 points, i.e. a rotation of 1 degree doesn't change epsilonDistance.
-        epsilonDistance *= (2 * Math.PI / 360) / deflectionAngle;
+        epsilonDistance *= ( 2 * Math.PI / 360 ) / deflectionAngle;
       }
       // clamp the value of epsilonDistance to be within this range
       epsilonDistance = dot.clamp( Math.abs( epsilonDistance ), MIN_EPSILON_DISTANCE, MAX_EPSILON_DISTANCE );
@@ -388,11 +382,11 @@ define( function( require ) {
       }, options );
 
       // if the line is open, there is one less segments than point vectors
-      var segmentsNumber = (options.isClosedLineSegments) ? positionArray.length : positionArray.length - 1;
+      var segmentsNumber = ( options.isClosedLineSegments ) ? positionArray.length : positionArray.length - 1;
 
       shape.moveToPoint( positionArray[ 0 ] );
       for ( var i = 1; i < segmentsNumber + 1; i++ ) {
-        shape.lineToPoint( positionArray[ (i) % positionArray.length ] );
+        shape.lineToPoint( positionArray[ ( i ) % positionArray.length ] );
       }
       return shape;
     }