Resolved How to keep UI objects inside screen | Screen Space - Overlay

Hello everyone!

I'm making this post since I've resolved an issue I've been struggling to find a proper solution on the Internet.

What is this about?
I had a UI panel that was being positioned in a Screen Space - Overlay canvas, through converting a 3D position to a 2D position (screen/canvas).

And I had to keep that UI panel inside the screen whether the original position wasn't on screen.

This worked like a charm for me. This might be done in better way, BUT it works properly.
For any recommendation/suggestion/comment, don't be afraid to tell me!

I haven't tried this code in Screen Space - Camera.
If I've missed a variable or something please also put it. Thanks.

Solution

Code (CSharp):

1.  
2.  
3.         [SerializeField] private Vector3 _offSet = Vector3.zero;
4.         [SerializeField] private Transform _parentTransform;
5.        
6.        
7.         private Camera _mainCamera;
8.         ///
9.         private Canvas _canvas;
10.         ///
11.         private RectTransform _rectTransform;
12.         ///
13.         private Vector3 _worldToScreenPointPosition;
14.         ///
15.         private Vector3 _fixedPosition;
16.         ///
17.         private float _correctedLeftX;
18.         private float _correctedRightX;
19.         ///
20.         private float _rectLeftX;
21.         private float _rectRightX;
22.         ///
23.         private float _actualRectWidth;
24.         ///
25.         private float _worldToScreenPointLeftX;
26.         private float _worldToScreenPointRightX;
27.         ///
28.         private Vector3[] _corners;
29.  
30.  
31.         private void Awake()
32.         {
33.             if (_parentTransform == null) Debug.LogError("ParentTransform missing! NULL ERROR");
34.  
35.             _mainCamera = Camera.main;
36.            
37.             _rectTransform = GetComponent<RectTransform>();
38.             _canvas = transform.parent.GetComponent<Canvas>();
39.         }
40.  
41.         private void FixedUpdate()
42.         {
43.             _worldToScreenPointPosition = _mainCamera.WorldToScreenPoint(_parentTransform.position + _offSet);
44.            
45.             //  Update UI panel position to fixed position
46.             KeepAlwaysOnScreen();
47.             //-----------------------------------------------
48.          
49.             //  Update position
50.             if (_rectTransform == null) return;
51.             if (_fixedPosition == Vector3.zero) _fixedPosition = _worldToScreenPointPosition;
52.  
53.             _rectTransform.position = _fixedPosition;
54.             //-----------------
55.         }
56.  
57.         void KeepAlwaysOnScreen()
58.         {
59.             //  Get real corners position
60.             _corners = new Vector3[4];
61.             _rectTransform.GetWorldCorners(_corners);
62.  
63.             _rectLeftX = _corners[0].x;     //  Current value of left X (corners[0] bottom-left corner)
64.             _rectRightX = _corners[3].x;    //  Current value of right X (corners[0] upper-right corner)
65.            
66.             _actualRectWidth = _rectRightX - _rectLeftX;
67.            
68.             _worldToScreenPointLeftX = _worldToScreenPointPosition.x - (_actualRectWidth / 2);   //  Original value of left X
69.             _worldToScreenPointRightX = _worldToScreenPointPosition.x + (_actualRectWidth / 2);  //  Original value of right X
70.            
71.            
72.             _fixedPosition = _worldToScreenPointPosition;
73.  
74.            
75.             //  LEFT SIDE
76.             if (_worldToScreenPointLeftX < 0)    //  Original value is wrong
77.             {
78.                 if (_rectLeftX < 0)  //  Current value is wrong
79.                 {
80.                     _correctedLeftX = _worldToScreenPointPosition.x - _rectLeftX + 1;
81.                     _fixedPosition = new Vector3(_correctedLeftX, _worldToScreenPointPosition.y, _worldToScreenPointPosition.z);
82.  
83.                     //Debug.LogWarning("CORRECTING LEFT SIDE");
84.                 }
85.                 else if (_correctedLeftX != 0)
86.                 {
87.                     _fixedPosition = new Vector3(_correctedLeftX, _worldToScreenPointPosition.y, _worldToScreenPointPosition.z);
88.                    
89.                     //Debug.LogWarning("LEFT SIDE CORRECTED");
90.                 }
91.             }
92.             //  RIGHT SIDE
93.             else if (_worldToScreenPointRightX > _canvas.renderingDisplaySize.x) //  Original value is wrong
94.             {
95.                 if (_rectRightX > _canvas.renderingDisplaySize.x)    //  Current value is wrong
96.                 {
97.                     _correctedRightX = _worldToScreenPointPosition.x - (_worldToScreenPointRightX - _canvas.renderingDisplaySize.x );
98.                     _fixedPosition = new Vector3(_correctedRightX, _worldToScreenPointPosition.y, _worldToScreenPointPosition.z);
99.                    
100.                     //Debug.LogWarning("CORRECTING RIGHT SIDE");
101.                 }
102.                 else if (_correctedRightX != 0)
103.                 {
104.                     _fixedPosition = new Vector3(_correctedRightX, _worldToScreenPointPosition.y, _worldToScreenPointPosition.z);
105.                    
106.                     //Debug.LogWarning("RIGHT SIDE CORRECTED");
107.                 }
108.             }
109.         }