From 20888bbb01a95e0f778a7358503b048b66192dd6 Mon Sep 17 00:00:00 2001
From: Chris Malley <cmalley@pixelzoom.com>
Date: Thu, 23 Dec 2021 10:21:46 -0700
Subject: [PATCH] add debugOpticalAxis query param,
 https://github.com/phetsims/geometric-optics/issues/283

---
 js/common/GOQueryParameters.ts              |  6 ++++++
 js/common/view/OpticalAxisForegroundNode.ts | 11 +++++++++--
 js/common/view/OpticalAxisNode.ts           |  1 +
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/js/common/GOQueryParameters.ts b/js/common/GOQueryParameters.ts
index 80e7a8d9..4a34a096 100644
--- a/js/common/GOQueryParameters.ts
+++ b/js/common/GOQueryParameters.ts
@@ -60,6 +60,12 @@ const SCHEMA = {
     type: 'number',
     defaultValue: 400,
     isValidValue: ( value: number ) => ( value >= 100 )
+  },
+
+  // The optical axis is drawn using 2 Nodes, OpticalAxisNode and OpticalAxisForegroundNode.
+  // This flag uses 'red' stroke for the segments drawn by OpticalAxisForegroundNode.
+  debugOpticalAxis: {
+    type: 'flag'
   }
 };
 
diff --git a/js/common/view/OpticalAxisForegroundNode.ts b/js/common/view/OpticalAxisForegroundNode.ts
index bd60e65a..bdec6f92 100644
--- a/js/common/view/OpticalAxisForegroundNode.ts
+++ b/js/common/view/OpticalAxisForegroundNode.ts
@@ -14,11 +14,13 @@ import Property from '../../../../axon/js/Property.js';
 import Bounds2 from '../../../../dot/js/Bounds2.js';
 import Vector2 from '../../../../dot/js/Vector2.js';
 import Shape from '../../../../kite/js/Shape.js';
+import merge from '../../../../phet-core/js/merge.js';
 import ModelViewTransform2 from '../../../../phetcommon/js/view/ModelViewTransform2.js';
 import geometricOptics from '../../geometricOptics.js';
 import Barrier from '../model/Barrier.js';
 import Representation from '../model/Representation.js';
 import OpticalAxisNode, { OpticalAxisNodeOptions } from './OpticalAxisNode.js';
+import GOQueryParameters from '../GOQueryParameters.js';
 
 class OpticalAxisForegroundNode extends OpticalAxisNode {
 
@@ -31,7 +33,7 @@ class OpticalAxisForegroundNode extends OpticalAxisNode {
    * @param barrier
    * @param modelBoundsProperty
    * @param modelViewTransform
-   * @param options
+   * @param providedOptions
    */
   constructor( opticPositionProperty: IReadOnlyProperty<Vector2>,
                representationProperty: IReadOnlyProperty<Representation>,
@@ -41,7 +43,12 @@ class OpticalAxisForegroundNode extends OpticalAxisNode {
                barrier: Barrier | null,
                modelBoundsProperty: IReadOnlyProperty<Bounds2>,
                modelViewTransform: ModelViewTransform2,
-               options: OpticalAxisNodeOptions ) {
+               providedOptions: OpticalAxisNodeOptions ) {
+
+    const options = merge( {}, providedOptions ) as OpticalAxisNodeOptions;
+    if ( GOQueryParameters.debugOpticalAxis ) {
+      options.stroke = 'red';
+    }
 
     // create optical axis line, with arbitrary length values.
     super( opticPositionProperty, modelBoundsProperty, modelViewTransform, options );
diff --git a/js/common/view/OpticalAxisNode.ts b/js/common/view/OpticalAxisNode.ts
index e3512b9a..9f830b01 100644
--- a/js/common/view/OpticalAxisNode.ts
+++ b/js/common/view/OpticalAxisNode.ts
@@ -21,6 +21,7 @@ import GOColors from '../GOColors.js';
 import GOConstants from '../GOConstants.js';
 
 type OpticalAxisNodeOptions = {
+  stroke?: ColorDef,
   visibleProperty: IProperty<boolean>
 };