@mui/x-internal-gestures/esm/core/utils/calculateRotationAngle.js

The core engine of GestureEvents, a modern and robust multi-pointer gesture detection library for JavaScript.

import { getAngle } from "./getAngle.js";

/**
 * Calculate the rotation angle between pointers
 * This uses the angle between the first two pointers relative to the centroid
 */
export function calculateRotationAngle(pointers) {
  if (pointers.length < 2) {
    return 0;
  }

  // For rotation, we need exactly 2 pointers
  // Use first two since they're most likely the primary pointers
  const p1 = {
    x: pointers[0].clientX,
    y: pointers[0].clientY
  };
  const p2 = {
    x: pointers[1].clientX,
    y: pointers[1].clientY
  };
  return getAngle(p1, p2);
}