[Unity] Get the position of the UI object on the screen

Obtain the relative position of the ui in its own Canvas and
the screen coordinates of the full-screen ui of the canvas are its position relative to the canvas plus 1/2 of the size of the canvas;

Canvas canvas = this.transform.GetComponentInParent<Canvas>();
RectTransform canvasRect = canvas.transform.GetComponent<RectTransform>();
//自身相对于Canvas的位置
Vector3 loadpos = canvas.transform.InverseTransformPoint(this.transform.position);
//屏幕位置
Vector3 screenPoint = loadpos + new Vector3(canvasRect.sizeDelta.x, canvasRect.sizeDelta.y, 0) / 2;