Unity 屏幕坐标到UGUI RectTransform本地坐标的转换

public static bool ScreenPointToLocalPointInRectangle(RectTransform rect, Vector2 screenPoint, Camera cam, out Vector2 localPoint); 

rect: 对应的 RectTransform 的引用
screenPoint: 位置，基于屏幕坐标系
cam: 相机的引用，如果Canvas的Render Mode 为 Screen Space - Camera 模式，则需要填入 Render Camera 对应的引用
localPoint: rect 本地坐标系下的坐标（原点(0,0)位置受Anchor的影响）
参考：
https://docs.unity3d.com/ScriptReference/RectTransformUtility.ScreenPointToLocalPointInRectangle.html

using UnityEngine; using UnityEngine.UI; using System.Collections; using UnityEngine.EventSystems;   public class GlobalTest : MonoBehaviour {     public Canvas canvas;     Text uiText;     RectTransform canvasRect;     RectTransform textRect;     void Start()     {         uiText = canvas.GetComponentInChildren<Text>();         canvasRect = canvas.GetComponent<RectTransform>();         textRect = uiText.GetComponent<RectTransform>();           Debug.Log(textRect.anchoredPosition);       }       void Update()     {         if (Input.GetMouseButtonUp(0))         {             Vector2 outVec;             if (RectTransformUtility.ScreenPointToLocalPointInRectangle(canvasRect,Input.mousePosition,null,out outVec))             {                 Debug.Log("Setting anchored positiont to: " + outVec);                 textRect.anchoredPosition = outVec;             }         }       } }

参考：
https://forum.unity.com/threads/issues-with-recttransformutility-screenpointtolocalpointinrectangle.437246/
再说一句
也可以从UGUI的EventSystem中获得鼠标基于屏幕坐标系的点击位置

    public void OnPointerDown(PointerEventData pointerEventData)     {         //Output the name of the GameObject that is being clicked         Debug.Log(name + "Game Object Click in Progress");     } 

https://docs.unity3d.com/ScriptReference/EventSystems.IPointerDownHandler.html