Module: Rubygame::Sprites::LimitGroup

Defined in:
lib/rubygame/sprite.rb

Overview

LimitGroup is a mix-in module that extends Group to limit the number of sprites it can contain. If the limit has been reached, each new sprite will “push out” the oldest sprite, on a First-In-First-Out basis.

The limit can be set either when the LimitGroup is created, or at any time during execution. However, if you reduce the limit, excess sprites will not be removed until the next time a sprite is added. (You can work around this by pushing the last sprite in the group again; the duplicate will be removed.)

Please note that, because Group#push is defined in terms of Group#<<, both LimitGroup#<< and LimitGroup#push work properly, even though only LimitGroup#<< is defined.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#limit ⇒ Object

Returns the value of attribute limit.



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# File 'lib/rubygame/sprite.rb', line 443

def limit
  @limit
end

Class Method Details

.extend_object(obj) ⇒ Object

Defines and sets @limit = 1 when an existing object is extended.



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# File 'lib/rubygame/sprite.rb', line 446

def LimitGroup.extend_object(obj)
	super
	obj.limit = 1
end

Instance Method Details

#<<(sprite) ⇒ Object

Add sprite to the LimitGroup, removing the oldest member if necessary to keep under the limit. If sprite is already in the LimitGroup, it will be moved to the top of the queue.



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# File 'lib/rubygame/sprite.rb', line 459

def <<(sprite)
	if not include? sprite
		super(sprite)
		while length > @limit
			self.slice!(0)
		end
	else # move sprite to the back of the queue
		self.delete(sprite)
		super(sprite)
	end
end

#initialize(limit = 1) ⇒ Object

Initialize the LimitGroup and define @limit (as 1, by default).



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# File 'lib/rubygame/sprite.rb', line 452

def initialize(limit=1)
	@limit = limit
end