Get mouse position relative to UI element

Hello everybody,
So I have a UI element, specifically an image. When it's clicked, I want to know exactly where the mouse is, relative to the element's bottom-left. The anchors of the element are in its center. The element is not necessarily in the middle of the screen.
For example, when you click the bottom-left corner of the element, it should show (0,0). when you click the middle, it should show (element_width/2, element_height/2), etc.
I tried this naive method, but it didn't work:

Code (CSharp):

1. public override void OnPointerClick(PointerEventData eventData)
2. {
3.     base.OnPointerClick(eventData);
4.  
5.     Vector2 relativeToCenter = eventData.position - (Vector2)transform.position;
6.     Vector2 relativeToBottomLeft = relativeToCenter + (GetComponent<RectTransform>().sizeDelta / 2);
7.     Debug.Log(relativeToBottomLeft);
8. }

What am I missing?

 

You can try using RectTransformUtility.ScreenPointToLocalPointInRectangle.

It will probably give you the local position relative to the pivot, so if that isn't at the bottom left, you may need to account for that offset.

 

Thank you very much!
Here is the final code, for the people who might enter this thread looking for solutions:

Code (CSharp):

1. private Vector2 PointerDataToRelativePos(PointerEventData eventData)
2. {
3.     Vector2 result;
4.     Vector2 clickPosition = eventData.position;
5.     RectTransform thisRect = GetComponent<RectTransform>();
6.  
7.     RectTransformUtility.ScreenPointToLocalPointInRectangle(thisRect, clickPosition, null, out result);
8.     result += thisRect.sizeDelta / 2;
9.  
10.     return result;
11. }
12.  

I made two assumptions:
1. the mouse is inside the image. otherwise,

ScreenPointToLocalPointInRectangle()

will return

false

, so you might want to check it in your code.
2. the ui element is in render mode "screen space - overlay". not sure how much it affects anything, but it's good to know.

 

I am no expert but wouldn't it be smarter to put the "GetComponent" into start so the function doesn't always call it. The RectTransform shouldn't change normaly