import type { Point } from './types';

export function scaleFromLine(a: Point, b: Point, lengthMm: number): number | null {
  const lengthPx = Math.hypot(b.x - a.x, b.y - a.y);
  if (!(lengthMm > 0) || lengthPx < 1) return null;
  return lengthPx / lengthMm;
}