Layer Stimulus

Description

Layers are useful only in conjuction with masks.

A layer is a container for other stimuli. When displayed, it first renders its child stimuli into a single scene, against a transparent background. It then draws this composite scene on the stimulus display. If one of its children is a mask, the “masked out” regions become transparent or semi- transparent “windows”, through which any stimuli below the layer are visible.

For example, when displayed together, the following stimuli produce a red circle inside a green square:

rectangle the_background (
    color = 0,1,0
    x_size = 10
    )

layer the_layer {
    rectangle (
        color = 1,0,0
        x_size = 10
        )
    mask (
        mask = ellipse
        x_size = 10
        )
}

Signature

stimulus/layer

Optional Parameters

deferred

Options:

no

yes

explicit

Default:

no

Controls when the stimulus is loaded. If no, the stimulus is loaded at experiment load time. If yes, the stimulus is loaded the first time it is queued. If explicit, the stimulus must be loaded explictly with Load Stimulus.

display

Name of the display on which the stimulus will be presented. If omitted, the default display (if available) will be used.

Placement

Allowed at top level:	Yes
Allowed parent:	Folder, Frame List Stimulus, Layer Stimulus, List Replicator, Movie Stimulus, Range Replicator, Stimulus Group
Allowed children:	Stimulus