fix: Calibration Points Not Rendering for Low Point Counts (< 4)

[thechillbasu]

Description

The eye-tracking calibration system was failing to render calibration points when configured with fewer than 4 points (e.g., 2 or 3 points).

Technical Analysis:
The bug was traced to the generateRuntimePattern method used to calculate dynamic point coordinates. The logic attempts to distribute points evenly by calculating step sizes based on grid dimensions:

const stepY = usableHeight / (rows - 1);

For configurations with fewer than 4 points, the grid logic results in a single row (rows = 1). This causes the denominator (rows - 1) to become 0, leading to a Division by Zero error.

The resulting coordinates become NaN (Not a Number). Since the rendering engine cannot draw elements at invalid coordinates, the calibration screen remains blank, even though the application state indicates calibration is active.

Solution and Reasoning

I replaced the usage of the flawed generateRuntimePattern with the existing, robust generateCalibrationPattern method.

Why this is the correct fix:
Instead of patching the faulty logic in generateRuntimePattern, switching to generateCalibrationPattern leverages a proven implementation that explicitly handles edge cases for 1-row or 1-column layouts. It correctly calculates coordinates for any number of points without division errors, ensuring stability and preventing similar regressions.

Before and After

Before (Bug)

The calibration screen remains blank with 2 points configured.

before-fix-points.mov

After (Fix)

The calibration points appear correctly and function as expected.

after-fix.points.mov

Closes #110