UGUI镜像翻转Image

https://blog.icemark.cn/?p=404

namespace UnityEngine.UI.Extensions
{
    [RequireComponent(typeof(RectTransform), typeof(Graphic)), DisallowMultipleComponent]
    [AddComponentMenu("UI/Effects/Extensions/Flippable")]
    public class UIFlippable : MonoBehaviour, IMeshModifier
    {     
        [SerializeField] private bool _horizontal = false;
        [SerializeField] private bool _veritical = false;
     
        public bool horizontal
        {
            get { return _horizontal; }
            set { _horizontal = value; OnValidate(); }
        }
     
        public bool vertical
        {
            get { return _veritical; }
            set { _veritical = value; OnValidate(); }
        }
     
        protected void OnValidate()
        {
            GetComponent().SetVerticesDirty();
        }
     
        public void ModifyMesh(VertexHelper verts)
        {
            RectTransform rt = transform as RectTransform;
         
            for (int i = 0; i < verts.currentVertCount; ++i)
            {
                UIVertex uiVertex = new UIVertex();
                verts.PopulateUIVertex(ref uiVertex,i);
 
                // Modify positions
                uiVertex.position = new Vector3(
                    (_horizontal ? (uiVertex.position.x + (rt.rect.center.x - uiVertex.position.x) * 2) : uiVertex.position.x),
                    (_veritical ?  (uiVertex.position.y + (rt.rect.center.y - uiVertex.position.y) * 2) : uiVertex.position.y),
                    uiVertex.position.z
                );
 
                // Apply
                verts.SetUIVertex(uiVertex, i);
            }
        }
 
        public void ModifyMesh(Mesh mesh)
        {
            //Obsolete member implementation
        }
    }
}