lib/metro/animation/has_animations.rb
def animate(actor_or_actor_name,options,&block)
      options[:actor] = actor(actor_or_actor_name)
      options[:context] = self
      animation_group = SceneAnimation.build options, &block
      enqueue animation_group
    end
def animate(actor_or_actor_name,options,&block)
      options[:actor] = actor(actor_or_actor_name)
      options[:context] = self
      animation_group = SceneAnimation.build options, &block
      enqueue animation_group
    end
Define an animation from within another animation block, an event block
 or a method.

 @example Defining an animation that fades out the hero when they have
   died.

     class HellScene
       draws :hero

       def update
         if hero.dead?
           animate :hero, to: { alpha: 0 }, interval: 60.ticks do
             transition_to :game_over
           end
         end
       end

     end