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.
Defines and sets @limit = 1 when an existing object is extended.
# File lib/rubygame/sprite.rb, line 446 def LimitGroup.extend_object(obj) super obj.limit = 1 end
# 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