+### Resolving the 'view-transition-group' value ### {#vt-group-value-resolve}
+
+
+To get the document-scoped view transition group of an {{Element}} |element|, perform the following steps:
+
+ 1. Let |computedGroup| be the [=computed value=] of element's 'view-transition-group' property.
+ 1. If |computedGroup| is associated with |element|'s [=node document=], return |computedGroup|.
+ 1. Return ''view-transition-group/normal''.
+
+
+### Resolving the containing group name ### {#vt-containing-group-name-resolve}
+
+
+
+To resolve the nearest containing group name of an {{Element}} |element|, perform the following steps given a {{ViewTransition}} |viewTransition|:
+ 1. Assert: |element| participates in |viewTransition|.
+ 1. Let |ancestorGroup| be |element|'s nearest [=flat tree=] [=tree/ancestor=] who participates in |viewTransition| and whose [=document-scoped view transition group=] is not ''view-transition-group/normal''.
+ 1. If |ancestorGroup| exists, return |ancestorGroup|'s [=document-scoped view transition name=].
+ 1. Return ''view-transition-name/none''.
+
+
+### Resolving the group name ### {#vt-group-name-resolve}
+
+
+To resolve the
used group name of an {{Element}} |element|, perform the following steps given a {{ViewTransition}} |transition|:
-To get the
nearest containing group name for an {{Element}} |element|, perform the following steps:
+ 1. Assert: |element| participates in |transition|.
+ 1. Let |group| be |element|'s [=document-scoped view transition group=].
+ 1. Let |containingGroupName| be |element|'s [=nearest containing group name=] given |transition|.
+ 1. Return the first matching statement, switching on |group|:
- 1. Let |nearestAncestorWithContain| be |element|'s nearest ancestor whose 'view-transition-name' [=computed value=] is not ''view-transition-name/none'' and whose 'view-transition-group' [=computed value=] is ''view-transition-group/contain''.
- 1. If |nearestAncestorWithContain| is null, return ''view-transition-group/none''.
- 1. Otherwise, return |nearestAncestorWithContain|'s 'view-transition-name' [=computed value=].
+
+ : normal
+ : contain
+ :: |containingGroupName|.
+
+ Note: an element with ''view-transition-group/contain'' becomes the [=nearest containing group name=] for its descendants.
+
+ : nearest
+ :: The [=document-scoped view transition name=] of the element's nearest [=flat tree=] ancestor which participates in the |transition|.
+
+ : <>
+ :: |group| if the element has a [=flat tree=] [=tree/ancestor=] whose [=document-scoped view transition name=] is |group| and participates in |transition|; Otherwise |containingGroupName|.
+
### Compute the old 'view-transition-group' ### {#vt-group-capture-old}
-When [[css-view-transitions-1#capture-old-state-algorithm|capturing the old state for an element]], perform the following steps given a [=captured element=] |capturedElement|, and an [=element=] |element|:
+When [[css-view-transitions-1#capture-old-state-algorithm|capturing the old state for an element]], perform the following steps given a [=captured element=] |capturedElement|, a {{ViewTransition}} |transition|, and an [=element=] |element|:
- 1. Set |capturedElement|'s [=captured element/containing group name=] to the [=used value=] of |element|'s ''view-transition-group''.
+ 1. Set |capturedElement|'s [=captured element/containing group name=] to |element|'s [=used group name=] given |transition|.
### Compute the new 'view-transition-group' ### {#vt-group-capture-new}
-When [[css-view-transitions-1#capture-new-state-algorithm|capturing the new state for an element]], perform the following steps given a [=captured element=] |capturedElement| and an [=element=] |element|:
+When [[css-view-transitions-1#capture-new-state-algorithm|capturing the new state for an element]], perform the following steps given a [=captured element=] |capturedElement| a {{ViewTransition}} |transition|, and an [=element=] |element|:
- 1. Set |capturedElement|'s [=captured element/containing group name=] to the [=used value=] of |element|'s 'view-transition-group'.
+ 1. Set |capturedElement|'s [=captured element/containing group name=] to |element|'s [=used group name=] given |transition|.
### Reparent a ''::view-transition-group()'' to its specified containing group ### {#vt-group-reparent}