Programming Reference:Stimulus Class

Location

src/shared/modules/application/stimuli

Synopsis

The Stimulus class is a virtual base class which defines an event handling interface for stimuli. There, a "Stimulus" is defined as "an object that can present (and possibly conceal) itself."

The Stimulus class is purely virtual; descendant classes need to implement its OnPresent() and OnConceal() event handlers.

An application uses the public Stimulus::Present() and Stimulus::Conceal() functions to control its behavior; these, in turn, call the virtual event handlers.

Properties

int Tag (rw)

An arbitrary integer that may be used to encode information about a given stimulus (e.g., its corresponding row in a configuration matrix).

Methods

Present()

Prompts a stimulus to present itself by calling its OnPresent() event handler.

Conceal()

Prompts a stimulus to conceal itself by calling its OnConceal() event handler.

Events

OnPresent

In its OnPresent event handler, a stimulus is supposed to present itself, e.g., to make itself visible, play itself if it is a sound or a movie, or highlight itself if it is a P300 matrix element.

OnConceal

In its OnConceal event handler, a stimulus is supposed to conceal itself, e.g., make itself invisible, or switch back to normal mode. For non-visual stimuli, this handler is typically empty.

This event is called Conceal rather than Hide because "Hide" is already used as a name for a GraphObject's function that makes it invisible.

Descendants

The Stimulus class is parent to a class hierarchy containing a number of auditory and visual stimuli:

Stimulus |-> VisualStimulus |-> ImageStimulus
         |                  |-> TextStimulus
         |-> AudioStimulus
         |-> SpeechStimulus
         |-> SoundStimulus

See also

Programming Reference:Association Class, Programming Reference:Target Class, Programming Reference:StimulusTask Class

Programming Reference:AudioStimulus Class, Programming Reference:ImageStimulus Class, Programming Reference:TextStimulus Class, Programming Reference:VisualStimulus Class,

Programming Reference:GraphObject Class