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Page Revision: 2013/10/17 20:04

Table of Contents [Hide/Show] Description Practical use     Instant mode     Fixation mode     Trapper mode Notes Properties     Genetic properties

Description ¶

ROI element creates a "region of interest" on the screen and continuously evaluates a positional input in relation to that area. The positional input can originate from any supported source, such as the system mouse (default), touchscreen or eye-tracker. The ROI element can detect specific input patterns, e.g. continuous fixations and saccades in and out of the region of the interest. The accurate timing statistics of such pattern is recorded by the element.

Practical use ¶

The ROI element can automatically detect the status changes in a positional input. If a change occurs the element gets triggered. The ROI element can work in one of three triggering modes:

Instant mode ¶

In this mode the element detects when positional input enters the element's region on the screen. As soon as it happens, the element get triggered- the time of event is recorded and snippets code executed, if it is defined).

Fixation mode ¶

In this mode the element detects when positional input enters the element's region on the screen and stays there for predefined time period. The period duration is defined by the [Fixation duration] property of the element. The element get triggered, if the duration is expired and input position still inside of the region. If the input position leaves the region before the duration is expired, the element is not triggered.

Trapper mode ¶

In this mode the element detect a moment when the input position leaves the element's region (assuming that it has been inside before onset of the parent event). This mode is handy for when breaks in previously archived fixation have to detected.

You can choose only between the rectangular or elliptical shape for the "element's region. It's sufficient for most of scenarios but, however, you can always create radar areas with complex shapes by combining several radar area elements in the same event. In this case, you may need to check the states of multiple radar area elements manually, in your snippets.

Notes ¶

1. The radar area element can be triggered only once during activation of the parent event. If you need multiple triggering, redesign your experiment flow (e.g. use several events) or reactivate the parent event. Alternately, reading [Is Over] property of the element will provide a status of positional input even after the element is triggered.
2. the radar area element can be affected by the solar visual transformations if they are applied to the parent event. In such cases, relations between positional input and watched areas can be incorrectly estimated. Always place radar area elements in events that have no such transformations.
3. if you have several active radar area elements that watch the same screen area they can be triggered at the same time.
   

Properties ¶

Genetic properties ¶

Name	Description	Attributes	Value Type
Settings
Area shape	Defines the shape of the “watched area”		stTargetShape
Border visible	Defines, if a border is shown around the ROI area at runtime.		Boolean
Radar provider	Defines which of the parent events in the layer hierarchy provides the positional data		String
Triggering mode	Defines the conditional mode that trigger the element.	D	stTargetHitMode
Fixation duration	Defines the duration (in ms) of the fixation interval when the element works in the "fixation" mode. Otherwise, the value is not used.	D,R	UInt64
Runtime info
Is Over	Indicates at the runtime if the positional input is currently inside of the "watched area".	R, Read-only	Boolean
Is Triggered	Indicates if the element has been triggered starting from current activation of the parent event.	R, Read-only	Boolean
Trigger time	Shows event's time (ms) when the element was triggered.	R, Read-only	UInt64
Visual appearance
AntiAliasing	if true, the rendered content will be antialiased for smoother visual appeariance. If false, rendering will be authentic to its source, e.g. a bitmap.		Boolean
Position	Position of the element on the screen area	D,R,*	clPoint (X.Y,R,Theta)
Size	Size of the element	D,R,*	clSize (Width,Height, aWidth,aHeight)
Z order	Indicates Z Order of the element on the given event	R, Read-only	Int32
Alignment	Defines alignment of the "watched" area to its position. The default value is the central alignment.	D,R,*	stAlignment Int32
Effects
Color mask	Produces a multiplicative combination of the original pixels and the selected mask color (except the alpha channel). The effect emulates a look through a colored glass. White or transparent mask color dont change the original pixels.	D,R,*	clColor
Saturation	Saturation of the rendered content.		Double

+=== Properties inherited from clElement === Inherited properties of clElement

Name	Description	Constraints	Value Type	Upon Change
Control
Is Enabled	If set to false the element is completely omitted when the experiment is run.	Design Time..	Boolean
Title	Title of the element.	Design Time..	String

The list of Text element properties:

Resource Holder inherited properties

CATEGORY ,Property name	Description	type	Value type
RESOURCE LIST
Resource index	The index of item in the resource list that is currently used by the element. Notice, that index starts from 1.	D,R,*	Int32
Resource count	The number of items loaded in the resource list of the element	D,R,Read-only	Int32