Custom editor for Unity Font objects.

FontEditor.cs

using UnityEngine;
using UnityEditor;
using System.Collections;

[CustomEditor(typeof(Font))]
public class FontEditor : Editor
{
	Font m_Font;
	
	static bool m_TilingControlsVisible;
	static int m_FirstCharacterIndex = 32;
	static int m_TilesU = 1;
	static int m_TilesV = 1;
	
	void OnEnable()
	{
		m_TilingControlsVisible = EditorPrefs.GetBool("FontEditor.TilingControlsVisible", false);
		m_FirstCharacterIndex = EditorPrefs.GetInt("FontEditor.FirstCharacterIndex", 32);
		m_TilesU = EditorPrefs.GetInt("FontEditor.TilesU", 1);
		m_TilesV = EditorPrefs.GetInt("FontEditor.TilesV", 1);
	}
	
	void OnDisable()
	{
		EditorPrefs.SetBool("FontEditor.TilingControlsVisible", m_TilingControlsVisible);
		EditorPrefs.SetInt("FontEditor.FirstCharacterIndex", m_FirstCharacterIndex);
		EditorPrefs.SetInt("FontEditor.TilesU", m_TilesU);
		EditorPrefs.SetInt("FontEditor.TilesV", m_TilesV);
	}
	
	public override void OnInspectorGUI()
	{
		m_Font = (Font)target;
		
		EditorGUILayout.BeginVertical("Box");
		m_TilingControlsVisible = EditorGUILayout.Foldout(m_TilingControlsVisible, "Tiling Controls");
		if(m_TilingControlsVisible)
		{
			EditorGUILayout.BeginHorizontal();
				m_FirstCharacterIndex = Mathf.Max(0, EditorGUILayout.IntField("First Character Index", m_FirstCharacterIndex));
				
				string character = GUILayout.TextField(((char)m_FirstCharacterIndex).ToString(), GUILayout.Width(20));
				if(character.Length > 0)
					m_FirstCharacterIndex = character[0];
			EditorGUILayout.EndHorizontal();
			
			EditorGUILayout.BeginHorizontal();
				EditorGUILayout.PrefixLabel("Tiling");
				m_TilesU = Mathf.Max(0, EditorGUILayout.IntField(m_TilesU));
				m_TilesV = Mathf.Max(0, EditorGUILayout.IntField(m_TilesV));
			EditorGUILayout.EndHorizontal();
			
			if(GUILayout.Button("Configure Character Rects"))
			{
				if(EditorUtility.DisplayDialog("Configure Character Rects",
					"This will erase all character rects and set them up again from scratch. Are you sure?",
					"OK", "Cancel"))
				{
					ConfigureCharacterRects();
					EditorUtility.SetDirty(m_Font);
				}
			}
		}
		EditorGUILayout.EndVertical();
		
		EditorGUILayout.Separator();
		base.OnInspectorGUI();
	}
	
	void ConfigureCharacterRects()
	{
		CharacterInfo[] characters = new CharacterInfo[m_TilesU * m_TilesV];
		
		float sizeU = 1.0f / m_TilesU;
		float sizeV = 1.0f / m_TilesV;
		
		for(int v = 0; v < m_TilesV; ++v)
		{
			for(int u = 0; u < m_TilesU; ++u)
			{
				var character = new CharacterInfo();
				character.index = m_FirstCharacterIndex + u + v * m_TilesU;
				character.uv = new Rect(u * sizeU,  1.0f - sizeV - v * sizeV, sizeU, sizeV);
				character.vert = new Rect(0, 0, 1, -1);
				character.size = 0;
				character.width = 1.0f;
				characters[u + v * m_TilesU] = character;
			}
		}
		
		m_Font.characterInfo = characters;
	}
}