Fixation Point Stimulus¶

Description¶

A rectangluar fixation point stimulus

Signature¶

stimulus/fixation_point

Required Parameters¶

trigger_width¶

Width of the (square) fixation window, which shares its center with the visible stimulus rectangle

trigger_watch_x¶

Variable containing the horizontal eye position

trigger_watch_y¶

Variable containing the vertical eye position

trigger_flag¶

Variable to which fixation status is written. When the subject’s gaze (as reported by trigger_watch_x and trigger_watch_y) enters the fixation window, the variable is set to true. When the subject’s gaze leaves the fixation window, the variable is set to false.

x_size¶

Example:	`5.0`

Horizontal size (degrees)

y_size¶

Example:	`5.0`

Vertical size (degrees)

Optional Parameters¶

color¶

Default:	`1.0,1.0,1.0`

The color of the stimulus, expressed as a comma-separated list of red, green, and blue components with values between 0 and 1 (inclusive). The list can include variable names in place of explicit values, in which case the corresponding component value will be read from the named variable.

x_position¶

Default:	`0.0`

Horizontal center position (degrees)

y_position¶

Default:	`0.0`

Vertical center position (degrees)

rotation¶

Default:	`0.0`

Rotation (degrees)

alpha_multiplier¶

Default:	`1.0`

Controls the transparency of the stimulus. 1.0 is fully opaque, while 0.0 is fully tranparent.

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.