xNode/Samples~/RuntimeMathGraph/Scripts/NodeDrag.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

namespace XNode.Examples.RuntimeMathNodes {
	public class NodeDrag : MonoBehaviour, IPointerClickHandler, IBeginDragHandler, IDragHandler, IEndDragHandler {
		private Vector3 offset;
		private UGUIMathBaseNode node;

		private void Awake() {
			node = GetComponentInParent<UGUIMathBaseNode>();
		}

		public void OnDrag(PointerEventData eventData) {
			node.transform.localPosition = node.graph.scrollRect.content.InverseTransformPoint(eventData.position) - offset;
		}

		public void OnBeginDrag(PointerEventData eventData) {
			Vector2 pointer = node.graph.scrollRect.content.InverseTransformPoint(eventData.position);
			Vector2 pos = node.transform.localPosition;
			offset = pointer - pos;
		}

		public void OnEndDrag(PointerEventData eventData) {
			node.transform.localPosition = node.graph.scrollRect.content.InverseTransformPoint(eventData.position) - offset;
			Vector2 pos = node.transform.localPosition;
			pos.y = -pos.y;
			node.node.position = pos;
		}

		public void OnPointerClick(PointerEventData eventData) {
			if (eventData.button != PointerEventData.InputButton.Right)
				return;

			node.graph.nodeContextMenu.selectedNode = node.node;
			node.graph.nodeContextMenu.OpenAt(eventData.position);
		}
	}
}