Class Rubygame::EventTriggers::KeyPressTrigger
In: lib/rubygame/event_triggers.rb
Parent: Object

KeyPressTrigger is an event trigger which fires when a key on the keyboard is pressed down (i.e. KeyPressed). See also KeyReleaseTrigger.

This trigger can be configured to fire for any key, or a specific key. It can also fire depending on which modifier keys are held (ctrl, shift, alt, etc.).

NOTE: This trigger only works with the new-style KeyPressed event class, not with the older KeyDownEvent. See EventQueue#enable_new_style_events


match?   new  

Public Class methods

Initialize a new instance of KeyPressTrigger with the given key and modifier keys.

key:the key symbol to detect, or :any (default) to detect any key. (Symbol, optional)
mods:an Array of one or more modifier key symbols, or :none to detect key presses with exactly no modifiers, or :any (default) to detect any key modifiers.

Valid modifiers are:

  • :alt, :left_alt, :right_alt,
  • :ctrl, :left_ctrl, :right_ctrl,
  • :shift, :left_shift, :right_shift,
  • :meta, :left_meta, :right_meta,
  • :numlock
  • :capslock
  • :mode

:alt, :ctrl, :shift, and :meta will match either the left version or right version (e.g. :left_alt or :right_alt).


  # Matches any key press, regardless of the key or modifiers.

  # Matches the 'A' key with any (or no) modifiers. :a )

  # Matches the 'A' with both Ctrl and Shift modifiers. :a, [:ctrl, :shift] )

  # Matches the 'A' with both Left Ctrl and Left Shift modifiers. :a, [:left_ctrl, :left_shift] )


# File lib/rubygame/event_triggers.rb, line 357
        def initialize( key=:any, mods=:any )
                @key = key
                @mods = mods

Public Instance methods

Returns true if the event is a KeyPressed event and the event’s key and mods BOTH match the trigger’s expectations.

Key matches if either of these is true:

  • the trigger’s key is the symbol :any
  • the event’s key is the same as the trigger’s key

Modifiers matches if any of these is true:

  • the trigger’s @mods is the symbol :any
  • the event has no modifiers and the trigger’s @mods is the symbol :none
  • every one of the trigger’s @mods matches one of the event’s modifiers. “Matches” means either it is the same symbol, or it is a more general version. For example, :alt will match either :left_alt or :right_alt.


# File lib/rubygame/event_triggers.rb, line 378
        def match?( event )
                if event.kind_of?( Rubygame::Events::KeyPressed )
                        ((@key == :any) or (event.key == @key)) and \
                        ((@mods == :any) or (@mods == :none and event.modifiers == [])\
                                         or (_mods_match?(event.modifiers)))