Function addMotionPathPointInScript

packages/parsers/src/gsapParser.ts:2969–2990

(
  script: string,
  animationId: string,
  index: number,
  point: { x: number; y: number },
)

 * No-op for missing animation/arc, out-of-range index, or cubic paths.
 */
export function addMotionPathPointInScript(
  script: string,
  animationId: string,
  index: number,
  point: { x: number; y: number },
): string {
  const loc = locateAnimation(script, animationId);
  if (!loc) return script;
  const anim = loc.target.animation;
  if (!anim.arcPath?.enabled || hasCubicSegments(anim.arcPath.segments)) return script;

  const waypoints = extractArcWaypoints(anim);
  // Insert strictly between two anchors: index 1..length-1.
  if (index < 1 || index > waypoints.length - 1) return script;

  const segments = [...anim.arcPath.segments];
  waypoints.splice(index, 0, { x: point.x, y: point.y });
  const splitCurviness = segments[index - 1]?.curviness ?? 1;
  segments.splice(index - 1, 0, { curviness: splitCurviness });

  return writeMotionPathValue(loc, waypoints, segments, anim.arcPath.autoRotate);
}

/**
 * Remove the waypoint at `index`. Refuses to drop below two anchors (a path