UI Image using Sprite Physics Shape for canvas raycasting

ImagePhysicsShapeRaycasting.cs

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

public class ImagePhysicsShapeRaycasting : Image, ICanvasRaycastFilter, ISerializationCallbackReceiver, ILayoutElement
{
    private List<Vector2> physicsShape = new List<Vector2>();

    new void Start()
    {
        base.Start();
        sprite.GetPhysicsShape(0, physicsShape);

        Rect spriteRect = rectTransform.rect; 
        float width = overrideSprite.texture.width;
        float height = overrideSprite.texture.height;
        for(int i= 0; i < physicsShape.Count; i++)
        {
            Vector2 point = physicsShape[i];
            Vector2 newPoint = new Vector2(point.x / (width * .005f) * (spriteRect.width * .5f), point.y / (height * .005f) * (spriteRect.height * .5f));
            physicsShape[i] = newPoint;
        }
    }

    public override bool IsRaycastLocationValid(Vector2 screenPoint, Camera eventCamera)
    {
        if (overrideSprite == null)
            return true;

        Vector2 local;
        if (!RectTransformUtility.ScreenPointToLocalPointInRectangle(rectTransform, screenPoint, eventCamera, out local))
            return false;

        return IsPointInPolygon(local, physicsShape);

    }

    public bool IsPointInPolygon(Vector2 point, List<Vector2> polygon)
    {
        int polygonLength = polygon.Count, i = 0;
        bool inside = false;
        // x, y for tested point.
        float pointX = point.x, pointY = point.y;
        // start / end point for the current polygon segment.
        float startX, startY, endX, endY;
        Vector2 endPoint = polygon[polygonLength - 1];
        endX = endPoint.x;
        endY = endPoint.y;
        while (i < polygonLength)
        {
            startX = endX; startY = endY;
            endPoint = polygon[i++];
            endX = endPoint.x; endY = endPoint.y;
            //
            inside ^= (endY > pointY ^ startY > pointY) /* ? pointY inside [startY;endY] segment ? */
                      && /* if so, test if it is under the segment */
                      ((pointX - endX) < (pointY - endY) * (startX - endX) / (startY - endY));
        }
        return inside;
    }
}