Gradient.cs

using System.Collections.Generic;

 /// <summary>
 /// Modified Gradient effect script from http://answers.unity3d.com/questions/1086415/gradient-text-in-unity-522-basevertexeffect-is-obs.html
 /// -Uses Unity's Gradient class to define the color
 /// -Offset is now limited to -1,1
 /// -Multiple color blend modes
 ///
 /// Remember that the colors are applied per-vertex so if you have multiple points on your gradient where the color changes and there aren't enough vertices, you won't see all of the colors.
 /// </summary>
 namespace UnityEngine.UI {
     [AddComponentMenu("UI/Effects/Gradient")]
     public class Gradient : BaseMeshEffect {
         [SerializeField]
         Type _gradientType;

         [SerializeField]
         Blend _blendMode = Blend.Multiply;

         [SerializeField]
         [Range(-1, 1)]
         float _offset = 0f;

         [SerializeField]
         UnityEngine.Gradient _effectGradient = new UnityEngine.Gradient() { colorKeys = new GradientColorKey[] { new GradientColorKey(Color.black, 0), new GradientColorKey(Color.white, 1) } };

         #region Properties
         public Blend BlendMode {
             get { return _blendMode; }
             set { _blendMode = value; }
         }

         public UnityEngine.Gradient EffectGradient {
             get { return _effectGradient; }
             set { _effectGradient = value; }
         }

         public Type GradientType {
             get { return _gradientType; }
             set { _gradientType = value; }
         }

         public float Offset {
             get { return _offset; }
             set { _offset = value; }
         }
         #endregion

         public override void ModifyMesh(VertexHelper helper) {
             if(!IsActive() || helper.currentVertCount == 0)
                 return;

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

             helper.GetUIVertexStream(_vertexList);

             int nCount = _vertexList.Count;
             switch(GradientType) {
                 case Type.Horizontal: {
                         float left = _vertexList[0].position.x;
                         float right = _vertexList[0].position.x;
                         float x = 0f;

                         for(int i = nCount - 1; i >= 1; --i) {
                             x = _vertexList[i].position.x;

                             if(x > right) right = x;
                             else if(x < left) left = x;
                         }

                         float width = 1f / (right - left);
                         UIVertex vertex = new UIVertex();

                         for(int i = 0; i < helper.currentVertCount; i++) {
                             helper.PopulateUIVertex(ref vertex, i);

                             vertex.color = BlendColor(vertex.color, EffectGradient.Evaluate((vertex.position.x - left) * width - Offset));

                             helper.SetUIVertex(vertex, i);
                         }
                     }
                     break;

                 case Type.Vertical: {
                         float bottom = _vertexList[0].position.y;
                         float top = _vertexList[0].position.y;
                         float y = 0f;

                         for(int i = nCount - 1; i >= 1; --i) {
                             y = _vertexList[i].position.y;

                             if(y > top) top = y;
                             else if(y < bottom) bottom = y;
                         }

                         float height = 1f / (top - bottom);
                         UIVertex vertex = new UIVertex();

                         for(int i = 0; i < helper.currentVertCount; i++) {
                             helper.PopulateUIVertex(ref vertex, i);

                             vertex.color = BlendColor(vertex.color, EffectGradient.Evaluate((vertex.position.y - bottom) * height - Offset));

                             helper.SetUIVertex(vertex, i);
                         }
                     }
                     break;
             }
         }

         Color BlendColor(Color colorA, Color colorB) {
             switch(BlendMode) {
                 default: return colorB;
                 case Blend.Add: return colorA + colorB;
                 case Blend.Multiply: return colorA * colorB;
             }
         }

         public enum Type {
             Horizontal,
             Vertical
         }

         public enum Blend {
             Override,
             Add,
             Multiply
         }
     }
 }