Unity 获取UI上某字的坐标点

转自： https://www.cnblogs.com/Jason-c/p/10573567.html

using System.Collections;
using UnityEngine;
using UnityEngine.UI;

public class TextMoveHelper : MonoBehaviour {

    public Text textComp;
    public Canvas canvas;
   
    public Text text;

    public Vector3 GetPosAtText(Canvas canvas, Text text,string strFragment)
    {
        int strFragmentIndex = text.text.IndexOf(strFragment);//-1表示不包含strFragment
        Vector3 stringPos = Vector3.zero;
        if (strFragmentIndex>-1)
        {
            Vector3 firstPos = GetPosAtText(canvas, text, strFragmentIndex + 1);
            Vector3 lastPos= GetPosAtText(canvas, text, strFragmentIndex+strFragment.Length);
            stringPos = (firstPos + lastPos) * 0.5f;
        }
        else
        {
            stringPos= GetPosAtText(canvas, text, strFragmentIndex);
        }
        return stringPos;
    }

    /// 

    /// 得到Text中字符的位置；canvas:所在的Canvas，text:需要定位的Text,charIndex:Text中的字符位置
    /// 
    public Vector3 GetPosAtText(Canvas canvas,Text text,int charIndex)
    {
        string textStr = text.text;
        Vector3 charPos = Vector3.zero;
        if (charIndex <= textStr.Length && charIndex > 0)
        {
            TextGenerator textGen = new TextGenerator(textStr.Length);
            Vector2 extents = text.gameObject.GetComponent().rect.size;
            textGen.Populate(textStr, text.GetGenerationSettings(extents));

            int newLine = textStr.Substring(0, charIndex).Split('\n').Length - 1;
            int whiteSpace = textStr.Substring(0, charIndex).Split(' ').Length - 1;
            int indexOfTextQuad = (charIndex * 4) + (newLine * 4) - 4;
            if (indexOfTextQuad < textGen.vertexCount)
            {
                charPos = (textGen.verts[indexOfTextQuad].position +
                    textGen.verts[indexOfTextQuad + 1].position +
                    textGen.verts[indexOfTextQuad + 2].position +
                    textGen.verts[indexOfTextQuad + 3].position) / 4f;
                

            }
        }
        charPos /= canvas.scaleFactor;//适应不同分辨率的屏幕
        charPos = text.transform.TransformPoint(charPos);//转换为世界坐标
        return charPos;
    }

    string a = "跟";
    string b = "一起";
    string c = "学习";
    string d = "学习中文";
    int i = 0;
    void OnGUI()
    {
        if (GUI.Button(new Rect(10, 10, 100, 80), "Test"))
        {
            switch (i)
            {
                case 0:
                    StartCoroutine(LerpMove(a));
                    break;
                case 1:
                    StartCoroutine(LerpMove(b));
                    break;
                case 2:
                    StartCoroutine(LerpMove(c));
                    break;
                case 3:
                    StartCoroutine(LerpMove(d));
                    i = -1;
                    break;
            }
            i++;
        
        }
    }
    IEnumerator LerpMove(string content)
    {
        text.text = content;
        text.rectTransform.position = GetPosAtText(canvas, textComp, content);
        Vector3 endPos = canvas.transform.TransformPoint(Vector3.zero);
        yield return new WaitForSeconds(0.3f);
        yield return new WaitUntil(() =>{
        text.rectTransform.position = Vector3.Lerp(text.rectTransform.position, endPos, Time.deltaTime);
            return Vector3.Distance(text.rectTransform.position, endPos) <0.1f;

        });

    }

}