From 837168f2f174bdb94c457601e529361b98e59101 Mon Sep 17 00:00:00 2001
From: Théo de la Hogue
Date: Mon, 30 Jan 2023 17:51:48 +0100
Subject: Refactoring realtime gaze movement identification.

---
 .../DispersionBasedGazeMovementIdentifier.py       | 96 +++++++++++-----------
 1 file changed, 50 insertions(+), 46 deletions(-)

(limited to 'src')

diff --git a/src/argaze/GazeAnalysis/DispersionBasedGazeMovementIdentifier.py b/src/argaze/GazeAnalysis/DispersionBasedGazeMovementIdentifier.py
index 849223c..51286ee 100644
--- a/src/argaze/GazeAnalysis/DispersionBasedGazeMovementIdentifier.py
+++ b/src/argaze/GazeAnalysis/DispersionBasedGazeMovementIdentifier.py
@@ -370,86 +370,90 @@ class TobiiDataStream_GazeMovementIdentifier():
 
     def __post_init__(self):
 
-        self.__valid_gaze_positions = GazeFeatures.TimeStampedGazePositions()
-        self.__current_fixation = None
-        self.__current_saccade = None
+        self.__valid_positions = GazeFeatures.TimeStampedGazePositions()
+        self.__fixation_positions = GazeFeatures.TimeStampedGazePositions()
+        self.__saccade_positions = GazeFeatures.TimeStampedGazePositions()
 
     def identify(self, ts, gaze_position):
 
+        # Ignore non valid gaze position
+        #if not gaze_position.valid:
+        #    return
+
         # Check if too much time elapsed since last gaze position
-        if len(self.__valid_gaze_positions) > 0:
+        if len(self.__valid_positions) > 0:
 
-            ts_last, _ = self.__valid_gaze_positions.last
+            ts_last, _ = self.__valid_positions.last
 
             if (ts - ts_last) > self.duration_min_threshold:
 
-                # Clear valid positions
-                self.__valid_gaze_positions = GazeFeatures.TimeStampedGazePositions()
-
-                 # Clear current movements
-                self.__current_fixation = None
-                self.__current_saccade = None
+                # Clear all former gaze positions
+                self.__valid_positions = GazeFeatures.TimeStampedGazePositions()
+                self.__fixation_positions = GazeFeatures.TimeStampedGazePositions()
+                self.__saccade_positions = GazeFeatures.TimeStampedGazePositions()
 
         # Store gaze positions until a minimal duration 
-        self.__valid_gaze_positions[ts] = gaze_position
+        self.__valid_positions[ts] = gaze_position
 
-        first_ts, _ = self.__valid_gaze_positions.first
-        last_ts, _ = self.__valid_gaze_positions.last
+        first_ts, _ = self.__valid_positions.first
+        last_ts, _ = self.__valid_positions.last
 
         # Once the minimal duration is reached
         if last_ts - first_ts >= self.duration_min_threshold:
 
             # Calculate the deviation of valid gaze positions
-            extended_fixation = Fixation(self.__valid_gaze_positions)
-            deviation = extended_fixation.deviation_max
+            deviation = Fixation(self.__valid_positions).deviation_max
 
             # Valid gaze positions deviation small enough
             if deviation <= self.deviation_max_threshold:
 
-                # Clear current saccade
-                # Question : Should we emit a SaccadeStop event?
-                self.__current_saccade = None
+                # Store last saccade
+                last_saccade = self.current_saccade
 
-                # Start/extend current fixation
-                # Question : Should we emit a FixationStart event?
-                self.__current_fixation = extended_fixation
+                # Clear saccade positions
+                self.__saccade_positions = GazeFeatures.TimeStampedGazePositions()
 
-            # Valid gaze positions deviation too wide while extending fixation
-            elif self.__current_fixation != None:
+                # Copy valid gaze positions into fixation positions
+                self.__fixation_positions = self.__valid_positions.copy()
 
-                # Create saccade from last position of current fixation to current gaze position
-                # Question : Should we emit a SaccadeStart event?
-                saccade_positions = GazeFeatures.TimeStampedGazePositions()
-                last_ts, last_position = self.__current_fixation.positions.last
-                saccade_positions[last_ts] = last_position
-                saccade_positions[ts] = gaze_position
+                # Output last saccade
+                return last_saccade
+                
+            # Valid gaze positions deviation too wide while identifying fixation
+            elif len(self.__fixation_positions) > 0:
 
-                self.__current_saccade = Saccade(saccade_positions)
+                # Store last fixation
+                last_fixation = self.current_fixation
 
-                # Clear current fixation
-                # Question : Should we emit a FixationStop event?
-                self.__current_fixation = None
+                # Start saccade positions with current gaze position
+                self.__saccade_positions[ts] = gaze_position
 
-                # Reset valid positions with current gaze position
-                self.__valid_gaze_positions = GazeFeatures.TimeStampedGazePositions()
-                self.__valid_gaze_positions[ts] = gaze_position
+                # Clear fixation positions
+                self.__fixation_positions = GazeFeatures.TimeStampedGazePositions()
 
-            # Valid gaze positions deviation too wide with no current fixation
-            else:
+                # Clear valid positions
+                self.__valid_positions = GazeFeatures.TimeStampedGazePositions()
+
+                # Output last fixation
+                return last_fixation
 
-                # Create saccade with valid gaze positions
-                self.__current_saccade = Saccade(self.__valid_gaze_positions)
+            # Valid gaze positions deviation too wide while identifying saccade (or not)
+            else:
 
-                # Reset valid positions with current gaze position
-                self.__valid_gaze_positions = GazeFeatures.TimeStampedGazePositions()
-                self.__valid_gaze_positions[ts] = gaze_position
+                # Move oldest valid position into saccade positions
+                first_ts, first_position = self.__valid_positions.pop_first()
+                self.__saccade_positions[first_ts] = first_position
 
     @property
     def current_fixation(self) -> FixationType:
 
-        return self.__current_fixation
+        if len(self.__fixation_positions) > 0:
+
+            return Fixation(self.__fixation_positions)
 
     @property
     def current_saccade(self) -> SaccadeType:
 
-        return self.__current_saccade
+        if len(self.__saccade_positions) > 0:
+            
+            return Saccade(self.__saccade_positions)
-- 
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