Unity UGUI 字体加粗特效

1.前言

在项目组无可厚非会在一些描述的文本中加入粗体，比如标题或者是重要文字，然而Unity本身UGUI提供的Text的Bold属性在某些字体达到的效果并不尽人意，可以先看下原本Unity的效果：

2.优化(一)

原本的效果肯定是不满足美术需求的，我们需要通过字体渲染方面重新实现字体加粗效果，在本文中核心算法其实就是将文本重复绘制，也就是在同样的位置绘制某个字符网格多次，可以近似实现这个字符的加粗效果。

using UnityEngine;
using System.Collections.Generic;
using UnityEngine.UI;
[RequireComponent(typeof(Text))]
public class BoldTextEffect : BaseMeshEffect
{
	[Range(0, 1)] public float Alpha;
	[Range(1, 5)] public int Strength;
	
	
	private Text m_Text = null;

	private Text TextComp
	{
		get
		{
			if (m_Text == null)
			{
				m_Text = GetComponent();
			}

			return m_Text;
		}
	}

	private Color effectColor
	{
		get
		{
			if (TextComp == null)
			{
				return Color.black;
			}

			return TextComp.color;
		}
	}
	

	protected void ApplyShadowZeroAlloc(List verts, Color32 color, int start, int end, float x, float y)
	{
		int num = verts.Count + end - start;
		if (verts.Capacity < num)
			verts.Capacity = num;
		for (int index = start; index < end; ++index)
		{
			UIVertex vert = verts[index];
			verts.Add(vert);
			Vector3 position = vert.position;
			position.x += x;
			position.y += y;
			vert.position = position;
			Color32 color32 = color;
			color32.a = (byte) ((int) color32.a * (int) verts[index].color.a / (int) byte.MaxValue);
			color32.a = (byte)(Alpha * color32.a);
			vert.color = color32;
			verts[index] = vert;
		}
	}

    public override void ModifyMesh(VertexHelper vh)
	{
		if (!IsActive())
		{
			return;
		}

		List verts = new List();
		vh.GetUIVertexStream(verts);


		for (int i = 0; i < Strength; ++i)
		{
			ApplyShadowZeroAlloc(verts, effectColor, 0, verts.Count, 0, 0);
		}
		
		vh.Clear();
		vh.AddUIVertexTriangleStream(verts);
    }
}

在上面这个组件中暴露了两个可供美术调节的参数：Alpha，Strength

• Alpha : 重复渲染字体网格的透明度，用于调整加粗的硬度
• Strength: 重复渲染字体网格的次数，用于调整加粗的强度

使用方法，只需要将这个组件挂载到Text物体上，调整上面两个参数直至效果满意为止，下面是示例图：

3.优化(二)

现在实现了控件级的字体加粗，我们还需要实现RichText的标签，也就是灵活的控制Text中某些字体的粗细效果。在这里实现的思路就是，通过记录标签的开始和结束为止，然后只在其区间内的字体网格进行绘制。

using UnityEngine;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using UnityEngine.UI;
[RequireComponent(typeof(Text))]
public class BoldTextEffect : BaseMeshEffect
{
	[Range(0, 1)] public float Alpha;
	[Range(1, 5)] public int Strength;

	public string RichText = "";	
	
	private Text m_Text = null;

	private Text TextComp
	{
		get
		{
			if (m_Text == null)
			{
				m_Text = GetComponent();
			}

			return m_Text;
		}
	}

	private Color effectColor
	{
		get
		{
			if (TextComp == null)
			{
				return Color.black;
			}

			return TextComp.color;
		}
	}
	
	protected void ApplyShadowZeroAlloc(List verts, Color32 color, int start, int end, float x, float y)
	{
		int num = verts.Count + end - start;
		if (verts.Capacity < num)
			verts.Capacity = num;
		for (int index = start; index < end; ++index)
		{
			UIVertex vert = verts[index];
			verts.Add(vert);
			Vector3 position = vert.position;
			position.x += x;
			position.y += y;
			vert.position = position;
			Color32 color32 = color;
			color32.a = (byte) ((int) color32.a * (int) verts[index].color.a / (int) byte.MaxValue);
			color32.a = (byte)(Alpha * color32.a);
			vert.color = color32;
			verts[index] = vert;
		}
	}
	
	private static readonly Regex s_BoldBeginRegex = new Regex("", RegexOptions.Singleline);
	private static readonly Regex s_BoldEndRegex = new Regex("", RegexOptions.Singleline);

	private MatchCollection begin = null;
	private MatchCollection end = null;
	
	
    public override void ModifyMesh(VertexHelper vh)
	{
		if (!IsActive())
		{
			return;
		}

		List verts = new List();
		vh.GetUIVertexStream(verts);

		
		if (!string.IsNullOrEmpty(RichText) && begin != null && end != null)
		{
			int offset = 0;
			for (int i = 0; i < begin.Count && i < end.Count; ++i)
			{
				for (int j = 0; j < Strength; ++j)
				{
					ApplyShadowZeroAlloc(verts, effectColor, (begin[i].Index - offset) * 6, (end[i].Index - offset - 3) * 6, 0, 0);
				}
				offset += 7;
			}
			
		}
		else
		{
			for (int i = 0; i < Strength; ++i)
			{
				ApplyShadowZeroAlloc(verts, effectColor, 0, verts.Count, 0, 0);
			}
		}
		
		
		vh.Clear();
		vh.AddUIVertexTriangleStream(verts);
    }


	public void SetText(string text)
	{
		this.RichText = text;
		begin = s_BoldBeginRegex.Matches(RichText);
		end = s_BoldEndRegex.Matches(RichText);
	
		text = text.Replace("", "");
		text = text.Replace("", "");

		if (m_Text != null)
		{
			m_Text.text = text;
		}
	}
	
}