Text Stimulus

Description

A stimulus that renders user-specified text within a rectangular region

Signature

stimulus/text

Required Parameters

text

Examples:

Hello, world!

"Good morning"

Text to display

font_name

Examples:

Helvetica Neue

"Courier"

Font name

font_size

Example:

24

Font size (points)

Optional Parameters

text_alignment

Options:

left

right

center

Default:

left

Text alignment

max_size_x

Maximum horizontal size (degrees).

If omitted, the maximum horizontal size is set to the value of x_size when the stimulus is loaded.

max_size_y

Maximum vertical size (degrees).

If omitted, the maximum vertical size is set to the value of y_size when the stimulus is loaded.

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. Each component may be described by any valid expression, but the expression must result in a value between 0 and 1 (inclusive).

alpha_multiplier

Default:

1.0

By default, the alpha multiplier controls the transparency of the stimulus. 1.0 is fully opaque, while 0.0 is fully tranparent.

Changes to the parameters source_blend_factor and dest_blend_factor can alter how (or if) the alpha multiplier is used.

source_blend_factor

Options:

zero

one

source_color

one_minus_source_color

dest_color

one_minus_dest_color

source_alpha

one_minus_source_alpha

dest_alpha

one_minus_dest_alpha

Default:

source_alpha

Source blending factor.

The parameters source_blend_factor, dest_blend_factor, source_alpha_blend_factor, and dest_alpha_blend_factor provide detailed control over how the color components and alpha multiplier of each fragment of the stimulus (the “source”) are combined with the color and alpha values already present in the framebuffer (the “destination”), which in turn result from blending the stimulus display background with any stimuli drawn beneath the source stimulus. These parameters correspond directly to the four arguments of the OpenGL function glBlendFuncSeparate. Please refer to that function’s reference page for explanations of the different blend factor options.

Note: Irrespective of the blend factors used, the blend equation is always GL_FUNC_ADD.

dest_blend_factor

Default:

one_minus_source_alpha

Destination blending factor. Accepts the same values as source_blend_factor.

source_alpha_blend_factor

Source alpha blending factor. Accepts the same values as source_blend_factor.

If omitted, the value of source_blend_factor is used.

dest_alpha_blend_factor

Destination alpha blending factor. Accepts the same values as source_blend_factor.

If omitted, the value of dest_blend_factor is used.

x_size

Example:

5.0

Horizontal size (degrees).

If omitted, the value of y_size is used. It is an error to omit both x_size and y_size (unless fullscreen is YES).

y_size

Example:

5.0

Vertical size (degrees).

If omitted, the value of x_size is used. It is an error to omit both x_size and y_size (unless fullscreen is YES).

x_position

Default:

0.0

Horizontal center position (degrees)

y_position

Default:

0.0

Vertical center position (degrees)

rotation

Default:

0.0

Rotation (degrees)

fullscreen

Default:

NO

If YES, the stimulus is sized to fill the display. In this mode, x_size, y_size, x_position, y_position, and rotation are ignored.

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:	Compound Stimulus, Folder, Frame List Stimulus, Layer Stimulus, List Replicator, Movie Stimulus, Range Replicator, Stimulus Group