Script the pipeline
===================

All gaze analysis pipeline objects are accessible from Python script.
This could be particularly useful for realtime gaze interaction applications.

## Load ArFrame configuration from dictionary

First of all, [ArFrame](../../../argaze.md/#argaze.ArFeatures.ArFrame) configuration can be loaded from a python dictionary.

```python
from argaze import ArFeatures

# Edit a dict with ArFrame configuration
configuration = {
	"name": "My FullHD screen",
    "size": (1920, 1080),
    ...
    "gaze_movement_identifier": {
        ...
    },
    "scan_path": {
        ...
    },
    "scan_path_analyzers": {
        ...
    },
    "heatmap": {
        ...
    },
    "layers": {
        "MyLayer": {
            ...
        },
        ...
    },
    "image_parameters": {
        ...
    }
}

# Load ArFrame
ar_frame = ArFeatures.ArFrame.from_dict(configuration)

# Do something with ArFrame
...
```

## Access to ArFrame and ArLayers attributes

Then, once the configuration is loaded, it is possible to access to its attributes: [read ArFrame code reference](../../../argaze.md/#argaze.ArFeatures.ArFrame) to get a complete list of what is available.

Thus, the [ArFrame.layers](../../../argaze.md/#argaze.ArFeatures.ArFrame) attribute allows to access each loaded layer and so, access to their attributes: [read ArLayer code reference](../../../argaze.md/#argaze.ArFeatures.ArLayer) to get a complete list of what is available.

```python
from argaze import ArFeatures

# Assuming the ArFrame is loaded
...

# Iterate over each ArFrame layers
for name, ar_layer in ar_frame.layers.items():
    ...
```

## Pipeline execution outputs

[ArFrame.look](../../../argaze.md/#argaze.ArFeatures.ArFrame.look) method returns many data about pipeline execution.

```python
# Assuming that timestamped gaze positions are available
...

    # Look ArFrame at a timestamped gaze position
    gaze_movement, scan_path_analysis, layers_analysis, execution_times, exception = ar_frame.look(timestamp, gaze_position)

    # Check if a gaze movement has been identified
    if gaze_movement.valid and gaze_movement.finished:

        # Do something with identified fixation
        if GazeFeatures.is_fixation(gaze_movement):
            ...

        # Do something with identified saccade
        elif GazeFeatures.is_saccade(gaze_movement):
            ...

        # Do something with scan path analysis
        for module, analysis in scan_path_analysis.items():
            for data, value in analysis.items():
                ...

        # Do something with each layer AOI scan path analysis
        for layer_name, layer_aoi_scan_path_analysis in layers_analysis.items():
            for module, analysis in layer_aoi_scan_path_analysis.items():
                for data, value in analysis.items():
                    ...

    # Do something with pipeline execution times
    ...

    # Do something with pipeline exception
    if exception:
        ...
```

Let's understand the meaning of each returned data.

### Gaze movement

A [GazeMovement](../../../argaze.md/#argaze.GazeFeatures.GazeMovement) once it have been identified by [ArFrame.gaze_movement_identifier](../../../argaze.md/#argaze.ArFeatures.ArFrame) object from incoming consecutive timestamped gaze positions. If no gaze movement have been identified, it returns an [UnvalidGazeMovement](../../../argaze.md/#argaze.GazeFeatures.UnvalidGazeMovement). 

This could also be the current gaze movement if [ArFrame.filter_in_progress_identification](../../../argaze.md/#argaze.ArFeatures.ArFrame) attribute is false.
In that case, the returned gaze movement *finished* flag is false.

Then, the returned gaze movement type can be tested thanks to [GazeFeatures.is_fixation](../../../argaze.md/#argaze.GazeFeatures.is_fixation) and [GazeFeatures.is_saccade](../../../argaze.md/#argaze.GazeFeatures.is_saccade) functions.

### Scan path analysis

A dictionary with all last scan path analysis if new scan step have been added to the [ArFrame.scan_path](../../../argaze.md/#argaze.ArFeatures.ArFrame) object.

### Layers analysis

A dictionary with all layers AOI scan path analysis if new AOI scan step have been added to an [ArLayer.aoi_scan_path](../../../argaze.md/#argaze.ArFeatures.ArLayer) object.

### Execution times

A dictionary with each pipeline step execution time.

### Exception

A [python Exception](https://docs.python.org/3/tutorial/errors.html#exceptions) object raised during pipeline execution.

## Setup ArFrame image parameters

[ArFrame.image](../../argaze.md/#argaze.ArFeatures.ArFrame.image) method parameters can be configured thanks to a python dictionary.

```python
# Assuming ArFrame is loaded
...

# Edit a dict with ArFrame image parameters
image_parameters = {
    "draw_scan_path": {
        ...
    },
    "draw_layers": {
        "MyLayer": {
            ...
        }
    },
    ...
}

# Pass image parameters to ArFrame
ar_frame_image = ar_frame.image(**image_parameters)

# Do something with ArFrame image
...
```