Unityのテキストを「両端揃え」「均等割り付け」対応

JustifyText.cs

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

[RequireComponent(typeof(Text))]
public class JustifyText : UIBehaviour, IMeshModifier
{
    /// <summary>
    /// 両端揃え
    /// </summary>
    public bool bothEnds = false;

    Text textComponent
    {
        get { return GetComponent<Text>(); }
    }
    float Width
    {
        get { return GetComponent<RectTransform>().sizeDelta.x; }
    }
    TextGenerator textGenerator
    {
        get { return textComponent.cachedTextGenerator; }
    }

    public void ModifyMesh(Mesh mesh)
    {
    }

    public void ModifyMesh(VertexHelper vh)
    {
        List<UIVertex> v = new List<UIVertex>();
        vh.GetUIVertexStream(v);

        List<UIVertex> newVertex = new List<UIVertex>();

        foreach (var line in GetLineInfo())
        {
            var vertices = v.Skip(line.start * 6).Take(line.count * 6).ToList();
            if (vertices.Count <= 0) continue;
            var textWidth = TextWidth(vertices);
            if (Width <= textWidth) return;

            var space = (Width - textWidth) / ((vertices.Count / 6) + (bothEnds ? -1 : 1));
            var offset = 0f;

            for (int i = (bothEnds ? 6 : 0); i < vertices.Count; i += 6)
            {
                offset += space;
                for (int j = 0; j < 6; j++)
                {
                    var index = i + j;
                    UIVertex vertex = vertices[index];
                    var pos = vertex.position;
                    pos.x += offset;
                    vertex.position = pos;
                    vertices[index] = vertex;
                }
            }
            newVertex.AddRange(vertices);
        }

        vh.Clear();
        vh.AddUIVertexTriangleStream(newVertex);
    }

    /// <summary>
    /// テキストの描画幅を取得する
    /// </summary>
    /// <returns></returns>
    private float TextWidth(List<UIVertex> verts)
    {
        var text = textComponent.text;
        UIVertex start = verts[0];
        UIVertex end = verts[verts.Count - 3];
        return end.position.x - start.position.x;
    }

    struct LineInfo
    {
        public int start;
        public int count;
    }

    List<LineInfo> GetLineInfo()
    {
        var lines = textGenerator.lines;

        List<LineInfo> res = new List<LineInfo>(lines.Count);

        for (int i = 0; i < lines.Count - 1; i++)
        {
            var start = lines[i].startCharIdx;
            var count = (lines[i + 1].startCharIdx - 1) - start;
            res.Add(new LineInfo { start = start, count = count });
        }
        {
            var last = lines.Last();
            var start = last.startCharIdx;
            var count = (textGenerator.characters.Count - 1) - start;

            res.Add(new LineInfo { start = start, count = count });
        }
        return res;
    }
}