Calculates evenly distributed coordinate positions for CAPTCHA characters.
Generates an array of [x, y] coordinates that distribute characters evenly
across the canvas width while adding random vertical positioning for security.
The coordinates are sorted by x-position to ensure proper left-to-right ordering.
Calculates evenly distributed coordinate positions for CAPTCHA characters.
Generates an array of [x, y] coordinates that distribute characters evenly across the canvas width while adding random vertical positioning for security. The coordinates are sorted by x-position to ensure proper left-to-right ordering.