TextTweenIn.cs

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

public class TextTweenIn : Text
{
	List<Vector3> charCorners = new List<Vector3>();
	List<float> _charScales = new List<float>();

	[SerializeField]
	float _scaleTime = 0.2f;

	[SerializeField]
	AnimationCurve _scaleCurve = new AnimationCurve();

	readonly UIVertex[] m_TempVerts = new UIVertex[4];

	bool _rebuildScales = false;
	string _prevText = "";

	protected override void OnPopulateMesh(VertexHelper toFill)
	{
		if (text != _prevText)
		{
			_rebuildScales = true;
			_charScales.Clear();
			StopAllCoroutines();

			_prevText = text;
		}

		if (font == null)
			return;

		// We don't care if we the font Texture changes while we are doing our Update.
		// The end result of cachedTextGenerator will be valid for this instance.
		// Otherwise we can get issues like Case 619238.
		m_DisableFontTextureRebuiltCallback = true;

		Vector2 extents = rectTransform.rect.size;

		var settings = GetGenerationSettings(extents);
		cachedTextGenerator.PopulateWithErrors(text, settings, gameObject);

		// Apply the offset to the vertices
		IList<UIVertex> verts = cachedTextGenerator.verts;
		float unitsPerPixel = 1 / pixelsPerUnit;
		//Last 4 verts are always a new line... (\n)
		int vertCount = verts.Count - 4;

		Vector2 roundingOffset = new Vector2(verts[0].position.x, verts[0].position.y) * unitsPerPixel;
		roundingOffset = PixelAdjustPoint(roundingOffset) - roundingOffset;
		toFill.Clear();

		if (roundingOffset != Vector2.zero)
		{
			for (int i = 0; i < vertCount; ++i)
			{
				int tempVertsIndex = i & 3;
				m_TempVerts[tempVertsIndex] = verts[i];
				m_TempVerts[tempVertsIndex].position *= unitsPerPixel;
				m_TempVerts[tempVertsIndex].position.x += roundingOffset.x;
				m_TempVerts[tempVertsIndex].position.y += roundingOffset.y;

				if (tempVertsIndex == 3)
					toFill.AddUIVertexQuad(m_TempVerts);
			}
		}
		else
		{
			charCorners.Clear();

			Vector3 averagePos = Vector3.zero;
			List<Vector3> averagePoses = new List<Vector3>();
			for (int i = 0; i < vertCount; ++i)
			{
				int tempVertsIndex = i & 3;
				m_TempVerts[tempVertsIndex] = verts[i];
				m_TempVerts[tempVertsIndex].position *= unitsPerPixel;

				averagePos += m_TempVerts[tempVertsIndex].position;

				if (tempVertsIndex == 3)
				{
					averagePos /= 4f;
					averagePoses.Add(averagePos);

					averagePos = Vector3.zero;
				}
			}

			for (int i = 0; i < vertCount; ++i)
			{
				int tempVertsIndex = i & 3;

				m_TempVerts[tempVertsIndex] = verts[i];
				m_TempVerts[tempVertsIndex].position *= unitsPerPixel;

				int characterIndex = i / 4;

				if ((_rebuildScales && i % 4 == 0) || characterIndex < _charScales.Count)
					_charScales.Add(0f);

				Vector3 toAverage = averagePoses[characterIndex] - m_TempVerts[tempVertsIndex].position;
				float offsetDist = 1f - _charScales[characterIndex];
				if (!Application.isPlaying)
					offsetDist = 0f;

				m_TempVerts[tempVertsIndex].position += toAverage * offsetDist;

				charCorners.Add(transform.position + m_TempVerts[tempVertsIndex].position * unitsPerPixel);

				if (tempVertsIndex == 3)
					toFill.AddUIVertexQuad(m_TempVerts);
			}
		}

		_rebuildScales = false;
		m_DisableFontTextureRebuiltCallback = false;
	}

	public void ForceAllScaled()
	{
		for (int i = 0; i < _charScales.Count; ++i)
			_charScales[i] = 1f;

		StopAllCoroutines();
		UpdateGeometry();
	}

	public void ScaleCharacter(int charIndex)
	{
		UpdateGeometry();
		StartCoroutine(ScaleCharacterRoutine(charIndex));
	}

	IEnumerator ScaleCharacterRoutine(int charIndex)
	{
		float timer = 0f;
		while (timer < _scaleTime)
		{
			timer += Time.deltaTime;

			_charScales[charIndex] = _scaleCurve.Evaluate(timer / _scaleTime);

			UpdateGeometry();
			yield return null;
		}
	}

	void OnDrawGizmosSelected()
	{
		for (int i = 0; i < charCorners.Count; i++)
		{
			if (i % 4 == 0)
			{
				Color color = Vector4.one * i / (float)charCorners.Count * 2f;
				color.a = 1;
				Gizmos.color = color;
			}

			Gizmos.DrawSphere(charCorners[i], 0.3f);
		}
	}
}