【Unity】【UI】テキストのサイズ調整を行うコンポーネントです

TextSizeAdjuster.cs

using UnityEngine;
using UnityEngine.UI;

/// <summary>
/// テキストのサイズ調整を行うコンポーネントです
/// </summary>
[ExecuteInEditMode]
[DisallowMultipleComponent]
[RequireComponent(typeof(Text))]
public class TextSizeAdjuster : MonoBehaviour
{
    public enum AdjustMode { None, Height, Width, HeightAndWidth }
    public AdjustMode Mode;

    public bool AlwaysUpdate;
    /// <summary>最大横幅 0以下で制限なし</summary>
    public float MaxWidth = -1f;
    /// <summary>最大縦幅 0以下で制限なし</summary>
    public float MaxHeight = -1f;
    /// <summary>最小横幅 0以下で制限なし</summary>
    public float MinWidth = -1f;
    /// <summary>最小縦幅 0以下で制限なし</summary>
    public float MinHeight = -1f;

    private Text text;
    private Text Text { get { return text ?? (text = GetComponent<Text>()); } }
    private Vector2 buffer = Vector2.zero;

    void Start()
    {
        Adjust();
    }

    void Update()
    {
        if (AlwaysUpdate) Adjust();
    }

    void OnValidate()
    {
        Adjust();
    }

    [ContextMenu("Adjust")]
    public void Adjust()
    {
        // 水平方向に制限をかける場合、Textを折り返し無し設定にする.
        // これを行わないとText.preferredWidthの値がText.textを更新した直後のみ大きい値をとる
        if ((Mode == AdjustMode.Width || Mode == AdjustMode.HeightAndWidth) && text.horizontalOverflow != HorizontalWrapMode.Overflow)
        {
            text.horizontalOverflow = HorizontalWrapMode.Overflow;
        }

        switch (Mode)
        {
            case AdjustMode.Height:
                AdjustHeight();
                break;
            case AdjustMode.Width:
                AdjustWidth();
                break;
            case AdjustMode.HeightAndWidth:
                AdjustBoth();
                break;
        }
    }

    void AdjustBoth()
    {
        var x = Text.preferredWidth;
        var y = Text.preferredHeight;
        if (MaxWidth > 0f && x > MaxWidth) x = MaxWidth;
        if (MinWidth > 0f && x < MinWidth) x = MinWidth;
        if (MaxHeight > 0f && y > MaxHeight) y = MaxHeight;
        if (MinHeight > 0f && y < MinHeight) y = MinHeight;
        buffer.x = x;
        buffer.y = y;
        Text.rectTransform.sizeDelta = buffer;
    }

    void AdjustHeight()
    {
        var x = Text.rectTransform.sizeDelta.x;
        var y = Text.preferredHeight;
        if (MaxWidth > 0f && x > MaxWidth) x = MaxWidth;
        if (MinWidth > 0f && x < MinWidth) x = MinWidth;
        if (MaxHeight > 0f && y > MaxHeight) y = MaxHeight;
        if (MinHeight > 0f && y < MinHeight) y = MinHeight;
        buffer.x = x;
        buffer.y = y;
        Text.rectTransform.sizeDelta = buffer;
    }

    void AdjustWidth()
    {
        var x = Text.preferredWidth;
        var y = Text.rectTransform.sizeDelta.y;
        if (MaxWidth > 0f && x > MaxWidth) x = MaxWidth;
        if (MinWidth > 0f && x < MinWidth) x = MinWidth;
        if (MaxHeight > 0f && y > MaxHeight) y = MaxHeight;
        if (MinHeight > 0f && y < MinHeight) y = MinHeight;
        buffer.x = x;
        buffer.y = y;
        Text.rectTransform.sizeDelta = buffer;
    }
}