Raspberry Pi Eye-Tracking Drawing

I am building a proof-of-concept that lets a Raspberry Pi follow a user’s gaze and immediately translate that data into visual output on an attached screen. At the end of the job I want to be able to look at a point on the display and watch the system draw a corresponding dot, line, or free-hand stroke in real time.

What I already have
• Raspberry Pi 4 with camera interface available
• Freedom to choose the most suitable eye-tracking library (OpenCV, MediaPipe, PyGaze, or similar)
• One HDMI monitor for testing, though the code should remain display-agnostic so I can later swap in a touchscreen or e-Ink panel without major refactoring.

What I need from you
• Set up and calibrate the camera-based eye tracker on the Pi
• Translate raw gaze coordinates into drawable vectors or cursor positions
• Render those vectors on the active framebuffer or via a lightweight GUI (Pygame, Kivy, or other Python toolkit)
• Commented Python code plus a quick-start readme so I can replicate the build on a fresh SD card.

Acceptance criteria
1. Calibration completes in under one minute.
2. Gaze-to-pixel latency below 80 ms is demonstrated with a simple FPS counter.
3. A short demo records me drawing a continuous spiral with nothing but eye movement.

If you have worked with low-latency vision pipelines on Pi or have an eye-tracking project to show, that will help me choose quickly.