ScrollRect - Center on child

Hi,

I was wondering if there is a component to center a ScrollRect on a child. Much like the UICenterOnChild component that NGUI has?

Adam

 

Hi mimminito!

I also have the same problem, Did you find out a solution?

Jopz

 

Hi,

Yes, after doing some more digging I found a solution. Below are a couple of links to help you out:

http://answers.unity3d.com/questions/776667/can-a-scroll-rect-snap-to-elements.html
http://forum.unity3d.com/threads/how-to-position-scrollrect-to-another-item.268794/

Adam

 

Code (CSharp):

1.  private Vector3 GetCenteredContentPosition(RectTransform child, ScrollRect scrollRect) {
2.         Vector3[] viewportCorners = new Vector3[4];
3.         RectTransform viewport = scrollRect.viewport;
4.         viewport = viewport != null ? viewport : (RectTransform) scrollRect.transform;
5.         viewport.GetWorldCorners(viewportCorners);
6.         Vector3 centreWorldPos = ((viewportCorners[1] - viewportCorners[0]) / 2f) + viewportCorners[0];
7.         float h = centreWorldPos.y - child.position.y;
8.         Vector3 displacement = new Vector3(0, h, 0);
9.         Vector3[] contentCorners = new Vector3[4];
10.         scrollRect.content.GetWorldCorners(contentCorners);
11.        
12.         if (contentCorners[1].y + displacement.y < viewportCorners[1].y) {
13.             displacement.y = viewportCorners[1].y - contentCorners[1].y;
14.         } else if (contentCorners[0].y + displacement.y > viewportCorners[0].y) {
15.             displacement.y = viewportCorners[0].y - contentCorners[0].y;
16.         }
17.         return scrollRect.content.position + displacement;
18.     }

 

Code (CSharp):

1.         private void CenterContentToTarget(ScrollRect scrollRect, RectTransform target)
2.         {
3.             float contentSize = scrollRect.content.rect.height;
4.             float viewportSize = scrollRect.viewport.rect.height;
5.             float halfViewportSize = viewportSize * 0.5f;
6.             Vector3 localPosition = scrollRect.content.InverseTransformPoint(target.position);
7.             scrollRect.verticalNormalizedPosition = (localPosition.y - halfViewportSize) / contentSize;
8.         }