testButt_IrregButton.cs

using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(RectTransform))]
[RequireComponent(typeof(Image))]
public class testButt_IrregButton : MonoBehaviour, ICanvasRaycastFilter
{
	private Image _image;
	private Sprite _sprite;
	
	void Start ()
	{
		_image = GetComponent<Image>();
	}
	
	public bool IsRaycastLocationValid(Vector2 sp, Camera eventCamera)
	{
		_sprite = _image.sprite;
		
		var rectTransform = (RectTransform)transform;
		Vector2 localPositionPivotRelative;
		RectTransformUtility.ScreenPointToLocalPointInRectangle((RectTransform) transform, sp, eventCamera, out localPositionPivotRelative);
		
		// convert to bottom-left origin coordinates
		var localPosition = new Vector2(localPositionPivotRelative.x + rectTransform.pivot.x*rectTransform.rect.width,
		                                localPositionPivotRelative.y + rectTransform.pivot.y*rectTransform.rect.height);
		
		var spriteRect = _sprite.textureRect;
		var maskRect = rectTransform.rect;
		
		var x = 0;
		var y = 0;
		// convert to texture space
		switch (_image.type)
		{
			
			case Image.Type.Sliced:
			{
				var border = _sprite.border;
				// x slicing
				if (localPosition.x < border.x)
				{
					x = Mathf.FloorToInt(spriteRect.x + localPosition.x);
				}
				else if (localPosition.x > maskRect.width - border.z)
				{
					x = Mathf.FloorToInt(spriteRect.x + spriteRect.width - (maskRect.width - localPosition.x));
				}
				else
				{
					x = Mathf.FloorToInt(spriteRect.x + border.x +
					                     ((localPosition.x - border.x)/
					 (maskRect.width - border.x - border.z)) *
					                     (spriteRect.width - border.x - border.z));
				}
				// y slicing
				if (localPosition.y < border.y)
				{
					y = Mathf.FloorToInt(spriteRect.y + localPosition.y);
				}
				else if (localPosition.y > maskRect.height - border.w)
				{
					y = Mathf.FloorToInt(spriteRect.y + spriteRect.height - (maskRect.height - localPosition.y));
				}
				else
				{
					y = Mathf.FloorToInt(spriteRect.y + border.y +
					                     ((localPosition.y - border.y) /
					 (maskRect.height - border.y - border.w)) *
					                     (spriteRect.height - border.y - border.w));
				}
			}
				break;
			case Image.Type.Simple:
			default:
			{
				// conversion to uniform UV space
				x = Mathf.FloorToInt(spriteRect.x + spriteRect.width * localPosition.x / maskRect.width);
				y = Mathf.FloorToInt(spriteRect.y + spriteRect.height * localPosition.y / maskRect.height);
			}
				break;
		}
		
		// destroy component if texture import settings are wrong
		try
		{
			return _sprite.texture.GetPixel(x,y).a > 0;
		}
		catch (UnityException e)
		{
			Debug.LogError("Mask texture not readable, set your sprite to Texture Type 'Advanced' and check 'Read/Write Enabled'");
			Destroy(this);
			return false;
		}
	}
}