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

public class OnZoomPanel : MonoBehaviour, IDragHandler, IBeginDragHandler, IEndDragHandler
{
    private RectTransform canvasRect;
    public RectTransform transRect;
    private Vector2 localPos;
    public float minWidth;
    public float minHeight;
    //private Vector2 offSet;

    void Start()
    {
        canvasRect = GameObject.Find("Canvas").GetComponent<RectTransform>();
        //transRect = GetComponent<RectTransform>();
        //offSet = localPos = Vector3.zero;
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left)//不是左键按下就不能拖拽
        {
            return;
        }
        if (RectTransformUtility.ScreenPointToLocalPointInRectangle(canvasRect, eventData.position, canvasRect.GetComponent<Canvas>().worldCamera, out localPos))
        {
            //offSet = localPos - new Vector2(transRect.localPosition.x, transRect.localPosition.y);
            InputManager.isDargUI = true;
            transform.SetAsLastSibling();
        }
    }

    public void OnDrag(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left) return;//不是左键按下就不能拖拽
        Vector2 newPos;
        if (RectTransformUtility.ScreenPointToLocalPointInRectangle(canvasRect, eventData.position, canvasRect.GetComponent<Canvas>().worldCamera, out newPos))
        {
            var dragOffset = newPos - localPos;
            var newX = transRect.sizeDelta.x + dragOffset.x;
            var newY = transRect.sizeDelta.y - dragOffset.y;
            if (newX < minWidth)
            {
                newX = minWidth;
            }
            if (newY < minHeight)
            {
                newY = minHeight;
            }
            transRect.sizeDelta = new Vector2(newX, newY);
            localPos = newPos;
        }
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left) return;//不是左键按下就不能拖拽
        InputManager.isDargUI = false;
    }
}