| """
|
| session_logger.py
|
| Phase 1: logs the live gaze stream to a per session file.
|
|
|
| Writes one line of JSON per frame to:
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| sessions/live/gaze_log.jsonl
|
|
|
| Fields per line:
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| t wall clock seconds (time.time()). Same epoch the browser uses
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| via Date.now()/1000, so gaze and DOM logs align by time.
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| sx, sy gaze in calibration screen space (SCREEN_W x SCREEN_H)
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| fx, fy gaze as a fraction of the screen (0..1). Phase 4 multiplies
|
| these by the browser viewport size to land on a real element.
|
|
|
| The file is truncated on each run, so one tracker run equals one clean session.
|
| """
|
|
|
| import os
|
| import json
|
| import time
|
|
|
|
|
| class GazeLogger:
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| def __init__(self, screen_w, screen_h, session_dir=os.path.join("sessions", "live")):
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| self.screen_w = float(screen_w)
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| self.screen_h = float(screen_h)
|
|
|
| os.makedirs(session_dir, exist_ok=True)
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| self.session_dir = session_dir
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| self.gaze_path = os.path.join(session_dir, "gaze_log.jsonl")
|
|
|
|
|
| self._f = open(self.gaze_path, "w", buffering=1)
|
|
|
| meta = {
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| "type": "meta",
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| "screen_w": screen_w,
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| "screen_h": screen_h,
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| "t": round(time.time(), 4),
|
| }
|
| self._f.write(json.dumps(meta) + "\n")
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| print(f"[GazeLogger] writing gaze stream to {self.gaze_path}")
|
|
|
| def log(self, sx, sy, t=None):
|
| if t is None:
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| t = time.time()
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| fx = sx / self.screen_w if self.screen_w else 0.0
|
| fy = sy / self.screen_h if self.screen_h else 0.0
|
| rec = {
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| "type": "gaze",
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| "t": round(t, 4),
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| "sx": round(float(sx), 2),
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| "sy": round(float(sy), 2),
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| "fx": round(float(fx), 5),
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| "fy": round(float(fy), 5),
|
| }
|
| self._f.write(json.dumps(rec) + "\n")
|
|
|
| def close(self):
|
| try:
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| self._f.close()
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| print(f"[GazeLogger] gaze log closed: {self.gaze_path}")
|
| except Exception:
|
| pass |
