Class: Object

Inherits:
BasicObject
Defined in:
lib/ext/object.rb,
lib/rubydraw/events.rb

Instance Method Summary collapse

Instance Method Details

#event? ⇒ Boolean

Returns false by default. Is overridden in Rubydraw::Events::Event#is_event?

Returns:

  • (Boolean) 


3
4
5
 
# File 'lib/rubydraw/events.rb', line 3

def event?
  false
end

#register_action(event, window = self, &block) ⇒ Object Also known as: whenever

Execute the given block on the appearance of an instance of event and pass that instance to the block.

Example:

class MyWindow < Rubydraw::Window
  def initialize
    super(300, 300)
    whenever(Rubydraw::Events::QuitRequest) do
      puts "Goodbye!"
      close
    end
    whenever(Rubydraw::Events::MouseMove) do |event|
      new_pos = event.position
      puts "Mouse moved to #{new_pos.x}, #{new_pos.y}.}"
    end
  end
end



19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
 
# File 'lib/ext/object.rb', line 19

def register_action(event, window=self, &block)
  # A very simple rule: +window+ must be a window. Therefore, since +window+ is self
  # by default, instances of Rubydraw::Window calling this method don't have to set
  # that parameter.
  unless window.is_a?(Rubydraw::Window)
    raise ArgumentError, "window must be a Rubydraw::Window"
  end
  event_block = window.registered_actions[event]
  # If nobody has registered a block for this event, prepare the way.
  if event_block.nil?
    window.registered_actions[event] = {}
  end
  # Now add the block.
  window.registered_actions[event][self] = block
end

#unregister_action(event, window = self) ⇒ Object

Adds the ability to remove actions from registered_actions. Useful if, for example, one were to implement a button that only works if it is shown.



39
40
41
42
43
44
 
# File 'lib/ext/object.rb', line 39

def unregister_action(event, window=self)
  unless window.is_a?(Rubydraw::Window)
    raise ArgumentError, "window must be a Rubydraw::Window"
  end
  window.registered_actions[event].delete(self)
end