Created
October 23, 2021 10:09
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Focus/center Scroll View to the specified point/item in Unity
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using System.Collections; | |
using UnityEngine; | |
using UnityEngine.UI; | |
public static class ScrollViewFocusFunctions | |
{ | |
public static Vector2 CalculateFocusedScrollPosition( this ScrollRect scrollView, Vector2 focusPoint ) | |
{ | |
Vector2 contentSize = scrollView.content.rect.size; | |
Vector2 viewportSize = ( (RectTransform) scrollView.content.parent ).rect.size; | |
Vector2 contentScale = scrollView.content.localScale; | |
contentSize.Scale( contentScale ); | |
focusPoint.Scale( contentScale ); | |
Vector2 scrollPosition = scrollView.normalizedPosition; | |
if( scrollView.horizontal && contentSize.x > viewportSize.x ) | |
scrollPosition.x = Mathf.Clamp01( ( focusPoint.x - viewportSize.x * 0.5f ) / ( contentSize.x - viewportSize.x ) ); | |
if( scrollView.vertical && contentSize.y > viewportSize.y ) | |
scrollPosition.y = Mathf.Clamp01( ( focusPoint.y - viewportSize.y * 0.5f ) / ( contentSize.y - viewportSize.y ) ); | |
return scrollPosition; | |
} | |
public static Vector2 CalculateFocusedScrollPosition( this ScrollRect scrollView, RectTransform item ) | |
{ | |
Vector2 itemCenterPoint = scrollView.content.InverseTransformPoint( item.transform.TransformPoint( item.rect.center ) ); | |
Vector2 contentSizeOffset = scrollView.content.rect.size; | |
contentSizeOffset.Scale( scrollView.content.pivot ); | |
return scrollView.CalculateFocusedScrollPosition( itemCenterPoint + contentSizeOffset ); | |
} | |
public static void FocusAtPoint( this ScrollRect scrollView, Vector2 focusPoint ) | |
{ | |
scrollView.normalizedPosition = scrollView.CalculateFocusedScrollPosition( focusPoint ); | |
} | |
public static void FocusOnItem( this ScrollRect scrollView, RectTransform item ) | |
{ | |
scrollView.normalizedPosition = scrollView.CalculateFocusedScrollPosition( item ); | |
} | |
private static IEnumerator LerpToScrollPositionCoroutine( this ScrollRect scrollView, Vector2 targetNormalizedPos, float speed ) | |
{ | |
Vector2 initialNormalizedPos = scrollView.normalizedPosition; | |
float t = 0f; | |
while( t < 1f ) | |
{ | |
scrollView.normalizedPosition = Vector2.LerpUnclamped( initialNormalizedPos, targetNormalizedPos, 1f - ( 1f - t ) * ( 1f - t ) ); | |
yield return null; | |
t += speed * Time.unscaledDeltaTime; | |
} | |
scrollView.normalizedPosition = targetNormalizedPos; | |
} | |
public static IEnumerator FocusAtPointCoroutine( this ScrollRect scrollView, Vector2 focusPoint, float speed ) | |
{ | |
yield return scrollView.LerpToScrollPositionCoroutine( scrollView.CalculateFocusedScrollPosition( focusPoint ), speed ); | |
} | |
public static IEnumerator FocusOnItemCoroutine( this ScrollRect scrollView, RectTransform item, float speed ) | |
{ | |
yield return scrollView.LerpToScrollPositionCoroutine( scrollView.CalculateFocusedScrollPosition( item ), speed ); | |
} | |
} |
Thanks
Great. thank you
Hello sir, I'd like to use your code but there is no license could you please add one when you have time :)
Thank you
@gimpycpu Hi! Feel free to use it under MIT License.
thanks man, your are a saviour for my stupid brain
public static bool cancelOutPreviousTask = false;
public static int runningLerpTask = 0;
private static async UniTask LerpToScrollPositionAsync(this ScrollRect scrollView, Vector2 targetNormalizedPos, float speed)
{
Vector2 initialNormalizedPos = scrollView.normalizedPosition;
float t = 0f;
while (t < 1f)
{
scrollView.normalizedPosition = Vector2.LerpUnclamped(initialNormalizedPos, targetNormalizedPos, 1f - (1f - t) * (1f - t));
await UniTask.Yield(PlayerLoopTiming.Update);
t += speed * Time.unscaledDeltaTime;
if (cancelOutPreviousTask)
{
t = 1;
cancelOutPreviousTask = false;
}
}
scrollView.normalizedPosition = targetNormalizedPos;
runningLerpTask--;
}
public static async UniTask FocusAtPointAsync(this ScrollRect scrollView, Vector2 focusPoint, float speed)
{
if (runningLerpTask > 0) cancelOutPreviousTask = true;
runningLerpTask++;
await scrollView.LerpToScrollPositionAsync(scrollView.CalculateFocusedScrollPosition(focusPoint), speed);
}
public static async UniTask FocusOnItemAsync(this ScrollRect scrollView, RectTransform item, float speed)
{
if (runningLerpTask > 0) cancelOutPreviousTask = true;
runningLerpTask++;
await scrollView.LerpToScrollPositionAsync(scrollView.CalculateFocusedScrollPosition(item), speed);
}
I prefer Unitask rather than old coroutine, here are some refactor codes
If you are using a content size filter and you have the position set incorrectly, use Canvas.ForceUpdateCanvases() before calling it
thank you so much, it works perfectly 💯
Thank you :)
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I can't express how I thank you. This works just perfect! Thank you very much.