import {getEventDistance} from './get-distance';
import type {PointerEventLike} from './types';

/**
 * calculate the scale factor between two pointersets
 * no scale is 1, and goes down to 0 when pinched together, and bigger when pinched out
 */
export function getScale(start: PointerEventLike[], end: PointerEventLike[]): number {
  return getEventDistance(end[0], end[1]) / getEventDistance(start[0], start[1]);
}