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Edit and execute pipeline
=========================
The [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) class defines a rectangular area where timestamped gaze positions are projected in and inside which they need to be analyzed.
Once defined, a gaze analysis pipeline needs to embedded inside a context that will provides it gaze positions to process.
## Edit JSON configuration
Here is a simple JSON [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) configuration example:
```json
{
"argaze.ArFeatures.ArFrame": {
"name": "My FullHD screen",
"size": [1920, 1080],
"gaze_movement_identifier": {
"argaze.GazeAnalysis.DispersionThresholdIdentification.GazeMovementIdentifier": {
"deviation_max_threshold": 50,
"duration_min_threshold": 200
}
},
"scan_path": {
"duration_max": 30000
},
"scan_path_analyzers": {
"argaze.GazeAnalysis.Basic.ScanPathAnalyzer": {},
"argaze.GazeAnalysis.ExploreExploitRatio.ScanPathAnalyzer": {
"short_fixation_duration_threshold": 0
}
}
}
}
```
Let's understand the meaning of each JSON entry.
### argaze.ArFeatures.ArFrame
The class name of the object being loaded.
### *name*
The name of the [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame). Basically useful for visualization purposes.
### *size*
The size of the [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) defines the dimension of the rectangular area where gaze positions are projected. Be aware that gaze positions have to be in the same range of value to be projected.
!!! warning "Free spatial unit"
Gaze positions can either be integers or floats, pixels, millimeters or what ever you need. The only concern is that all spatial values used in further configurations have to be in the same unit.
### *gaze_movement_identifier*
The first [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) pipeline step is to identify fixations or saccades from consecutive timestamped gaze positions.
The identification algorithm can be selected by instantiating a particular [GazeMovementIdentifier from the GazeAnalysis submodule](pipeline_modules/gaze_movement_identifiers.md) or [from another Python package](advanced_topics/module_loading.md).
In the example file, the chosen identification algorithm is the [Dispersion Threshold Identification (I-DT)](../../argaze.md/#argaze.GazeAnalysis.DispersionThresholdIdentification) which has two specific *deviation_max_threshold* and *duration_min_threshold* attributes.
!!! note
In ArGaze, [Fixation](../../argaze.md/#argaze.GazeFeatures.Fixation) and [Saccade](../../argaze.md/#argaze.GazeFeatures.Saccade) are considered as particular [GazeMovements](../../argaze.md/#argaze.GazeFeatures.GazeMovement).
!!! warning "Mandatory"
JSON *gaze_movement_identifier* entry is mandatory. Otherwise, the ScanPath and ScanPathAnalyzers steps are disabled.
### *scan_path*
The second [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) pipeline step aims to build a [ScanPath](../../argaze.md/#argaze.GazeFeatures.ScanPath) defined as a list of [ScanSteps](../../argaze.md/#argaze.GazeFeatures.ScanStep) made by a fixation and a consecutive saccade.
Once fixations and saccades are identified, they are automatically appended to the ScanPath if required.
The [ScanPath.duration_max](../../argaze.md/#argaze.GazeFeatures.ScanPath.duration_max) attribute is the duration from which older scan steps are removed each time new scan steps are added.
!!! note "Optional"
JSON *scan_path* entry is not mandatory. If *scan_path_analyzers* entry is not empty, the ScanPath step is automatically enabled.
### *scan_path_analyzers*
Finally, the last [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) pipeline step consists of passing the previously built [ScanPath](../../argaze.md/#argaze.GazeFeatures.ScanPath) to each loaded [ScanPathAnalyzer](../../argaze.md/#argaze.GazeFeatures.ScanPathAnalyzer).
Each analysis algorithm can be selected by instantiating a particular [ScanPathAnalyzer from the GazeAnalysis submodule](pipeline_modules/scan_path_analyzers.md) or [from another Python package](advanced_topics/module_loading.md).
In the example file, the chosen analysis algorithms are the [Basic](../../argaze.md/#argaze.GazeAnalysis.Basic) module and the [ExploreExploitRatio](../../argaze.md/#argaze.GazeAnalysis.ExploreExploitRatio) module, which has one specific *short_fixation_duration_threshold* attribute.
## Pipeline execution
A pipeline needs to be embedded into a context to be executed.
Copy the gaze analysis pipeline configuration defined above inside the following context configuration.
```json
{
"argaze.utils.contexts.Random.GazePositionGenerator": {
"name": "Random gaze position generator",
"range": [1920, 1080],
"pipeline": JSON CONFIGURATION
}
}
```
Then, use the [*load* command](../utils/main_commands.md) to execute the context.
```shell
python -m argaze load CONFIGURATION
```
This command should open a GUI window with a random yellow dot and identified fixations circles.
!!! note ""
At this point, the pipeline only processes gaze movement identification and scan path analysis without any AOI neither any recording or visualization supports.
Read the next chapters to learn how to [describe AOI](aoi_2d_description.md), [add AOI analysis](aoi_analysis.md), [record gaze analysis](recording.md) and [visualize pipeline steps](visualization.md).
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