Page History: ROI Element
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Page Revision: 2012/10/07 20:34
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ROI Element
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| Info |
| Category: |
Behaviour Control |
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AddIn: |
Base Elements |
| Creator: |
OkazoLab Team |
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Scope: |
Parent Event |
| Owns Snippets: |
no |
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Usage: |
Runtime Screen,Snippets |
Description
ROI element creates a "region of interest" area on the main screen and continuously evaluates a positional input in relation to that area. The elements can work in several modes which simplify implementation of the standard tracking tasks, such as fixation detection, smooth pursuits and fixation breaks. By default, the positional input to the element is provided by the system mouse but other sources, e.g eye trackers and joysticks, can be selected as well.
Practical use
The ROI element can automatically detect the status changes in a positional input. If a change occurs the element gets triggered. Each 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
- 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.
- 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.
- 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 |
| Working mode | Defines the working mode for the element- its reaction on the positional input. | 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. | | Boolean |
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| Title | Title of the element. | | String |
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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 |
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