Resizing a sprite that has a custom physics file? (P2/Phaser)

Question

I have a circular sprite (a pinball) with a Lime / Corona JSON physics file (exported from PhysicsEditor). The purpose of this file is so that the hitbox is actually circular.

It's working fine (for those not familiar with coffeescript, the @ just means this )

# in preload
@load.physics 'ball_physics', @Assets.ball_physics

# in create
@ball = @add_p2_sprite @ball_start_x, @ball_start_y, 'ball'
@ball.body.clearShapes()
@ball.body.loadPolygon 'ball_physics', 'ball'

The problem is that I cannot scale or resize the ball without messing up the hitbox. It seems like it always works off the original size. Is there any way to update this dynamically?

For example, here is using a non-resized sprite:

And here is with a sprite scaled to 0.5, 0.5:

Is there any way to do this other than creating new png and JSON files for the sprite?

---

here's a response to the comment, turning on debugMode so I see hitboxes outlined and scaling the ball before applying the physics file:

@ball =  @add.sprite @ball_start_x, @ball_start_y, 'ball'
@ball.scale.x = 2
@ball.scale.y = 2
@physics.p2.enable @ball, true
@add_physics_file(@ball, 'ball_physics', 'ball')
@collide_world_bounds(@ball)

The hitbox has not re-scaled:

Answer 1

I found a megmut user code, I tried it and it worked perfectly, you could try it:

function resizePolygon(originalPhysicsKey, newPhysicsKey, shapeKey, scale){
   var newData = [];
   var data = this.game.cache.getPhysicsData(originalPhysicsKey, shapeKey);

   for (var i = 0; i < data.length; i++) {
       var vertices = [];

       for (var j = 0; j < data[i].shape.length; j += 2) {
          vertices[j] = data[i].shape[j] * scale;
          vertices[j+1] = data[i].shape[j+1] * scale; 
       }

       newData.push({shape : vertices});
   }

   var item = {};
   item[shapeKey] = newData;
   game.load.physics(newPhysicsKey, '', item);

}

Just use:

    function preload() {
       game.load.image('contra2', 'contra2.png');

       game.load.physics('physicsData', 'sprites.json');
    }

    function create() {
       game.physics.startSystem(Phaser.Physics.P2JS);

       var scale = 1.5;
       resizePolygon('physicsData', 'robot', 'contra2', scale)

       contra = game.add.sprite(400, 300, 'contra2');
       contra.scale.setTo(scale, scale);

       game.physics.p2.enable(contra, true);

       contra.body.clearShapes();
       contra.body.loadPolygon('robot', 'contra2');
   }