[css-view-transitions-2] Editorial: refactor L2 concerns out of L1 #9892
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@@ -19,11 +19,15 @@ Markup Shorthands: css yes, markdown yes | |
| <pre class=link-defaults> | ||
| spec:css-view-transitions-1; | ||
| text: active view transition; type: dfn; | ||
| text: capture the old state; type: dfn; | ||
| text: clear view transition; type: dfn; | ||
| text: activate view transition; type: dfn; | ||
| text: skip the view transition; type: dfn; | ||
| text: ViewTransition; type: interface; | ||
| text: named elements; for: ViewTransition; type: dfn; | ||
| text: finished promise; for: ViewTransition; type: dfn; | ||
| text: ready promise; for: ViewTransition; type: dfn; | ||
| text: update callback; for: ViewTransition; type: dfn; | ||
| text: update callback done promise; for: ViewTransition; type: dfn; | ||
| text: initial snapshot containing block size; for: ViewTransition; type: dfn; | ||
| text: captured elements; type: dfn; | ||
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@@ -33,6 +37,7 @@ spec:css-view-transitions-1; | |
| text: perform pending transition operations; type: dfn; | ||
| text: setup view transition; type: dfn; | ||
| text: named view transition pseudo-element; type: dfn; | ||
| text: rendering suppression for view transitions; type: dfn; | ||
| spec:dom; type:dfn; text:document | ||
| spec:css22; type:dfn; text:element | ||
| spec:selectors-4; type:dfn; | ||
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@@ -446,13 +451,24 @@ Note: as per default behavior, the ''@view-transition'' rule can be nested insid | |
| <div algorithm="start-vt-with-options"> | ||
| The [=method steps=] for <dfn method for=Document>startViewTransition(|callbackOptions|)</dfn> are as follows: | ||
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| 1. Let |updateCallback| be null. | ||
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| 1. If |callbackOptions| is an an {{UpdateCallback}}, set |updateCallback| to |callbackOptions|. | ||
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| 1. Otherwise, if |callbackOptions| is a {{StartViewTransitionOptions}}, then set |updateCallback| to |callbackOptions|'s {{StartViewTransitionOptions/update}}. | ||
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| 1. If |this|'s [=active view transition=] is not null and its [=outbound post-capture steps=] is not null, | ||
| then: | ||
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| 1. Let |preSkippedTransition| be a new {{ViewTransition}} in |this|'s [=relevant realm=] whose [=ViewTransition/update callback=] is |updateCallback|. | ||
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| 1. [=Skip the view transition|Skip=] |preSkippedTransition| with an "{{InvalidStateError}}" {{DOMException}}. | ||
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Member
There was a problem hiding this comment. Step 4 in "Skip the view transition" algorithm in L1 needs to be updated to: "If document’s active view transition is transition, Set rendering suppression for view transitions to false." Otherwise this will resume rendering while the outbound transition is being captured.
Collaborator
Author
There was a problem hiding this comment. I still don't understand why we need rendering suppression. Is that for that unspecified async capture? |
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| 1. Return |preSkippedTransition|. | ||
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| 1. Let |viewTransition| be the result of running the [=method steps=] for {{Document/startViewTransition(updateCallback)}} given |updateCallback|. | ||
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| 1. If |callbackOptions| is a {{StartViewTransitionOptions}}, then set |viewTransition|'s [=ViewTransition/active types=] to |callbackOptions|'s {{StartViewTransitionOptions/type}}. | ||
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| 1. Return |viewTransition|. | ||
| </div> | ||
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@@ -484,14 +500,34 @@ The {{CSSViewTransitionRule}} represents a ''@view-transition'' rule. | |
| # Algorithms # {#algorithms} | ||
| ## Data Structures ## {#concepts} | ||
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| ### Additions to {{Document}} ### {#additions-to-document} | ||
| A {{Document}} additionaly has: | ||
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| <dl dfn-for=document> | ||
| : <dfn>inbound view transition params</dfn> | ||
| :: a [=view transition params=], or null. | ||
| Initially null. | ||
| </dl> | ||
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| ### The View transition params struct ### {#view-transition-params-struct} | ||
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| A <dfn>view transition params</dfn> is a [=struct=] whose purpose is to serialize view transition information across documents. | ||
| It has the following [=struct/items=]: | ||
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| <dl dfn-for="view transition params"> | ||
| : <dfn>named elements</dfn> | ||
| :: a [=/map=], whose keys are strings and whose values are [=captured elements=]. | ||
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| : <dfn>initial snapshot containing block size</dfn> | ||
| :: a [=tuple=] of two numbers (width and height). | ||
| </dl> | ||
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| ### Additions to {{ViewTransition}} ### {#view-transitions-extension} | ||
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| A {{ViewTransition}} additionally has: | ||
| <dl dfn-for=ViewTransition> | ||
| : <dfn>outbound post-capture steps</dfn> | ||
| :: Null or a set of steps, initially null. | ||
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| : <dfn>active types</dfn> | ||
| :: Null or a [=list=] of strings, initially null. | ||
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@@ -506,7 +542,7 @@ The [=captured element=] struct should contain these fields, in addition to the | |
| :: a [=/list=] of strings, initially empty. | ||
| </dl> | ||
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| ## Algorithm to capture 'view-transition-class': ## {#vt-class-algorithms} | ||
| <div algorithm="additional capture steps"> | ||
| When capturing the old or new state for an element, perform the following steps given a [=captured element=] |capture| and an [=element=] |element|: | ||
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@@ -515,6 +551,44 @@ When capturing the old or new state for an element, perform the following steps | |
| Note: This is written in a monkey-patch manner, and will be merged into the algorithm once the L1 spec graduates. | ||
| </div> | ||
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| ## Additions to skip steps: ## {#additional-skip-steps} | ||
| <div algorithm="additional skip steps"> | ||
| Append the following steps to [=skip the view transition=] given a {{ViewTransition}} |transition|: | ||
| 1. If |transition|'s [=outbound post-capture steps=] is not null, then run |transition|'s [=outbound post-capture steps=] with null. | ||
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| Note: This is written in a monkey-patch manner, and will be merged into the algorithm once the L1 spec graduates. | ||
| </div> | ||
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| ## Addition to pending transition operations ## {#additions-to-pending-transition-operation} | ||
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| Prepend this to the [=Perform pending transition operations=] algorithm given a {{Document}} |document|: | ||
| 1. If |document|'s [=active view transition=] is not null and its [=outbound post-capture steps=] is not null, then: | ||
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| 1. Assert: |document|'s [=active view transition=]'s [=ViewTransition/phase=] is "`pending-capture`". | ||
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| 1. Let |viewTransitionParams| be null; | ||
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| 1. Set |document|'s [=document/rendering suppression for view transitions=] to true. | ||
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| Issue: though [=capture the old state=] appears here as a synchronous step, it is in fact an asynchronous step | ||
| as rendering an element into an image cannot be done synchronously. This should be more explicit in the L1 spec. | ||
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| 1. [=Capture the old state=] for |transition|. | ||
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| 1. Set |document|'s [=document/rendering suppression for view transitions=] to false. | ||
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| 1. If this succeeded, then set |viewTransitionParams| to a new [=view transition params=] whose | ||
| [=view transition params/named elements=] is a [=map/clone=] of |transition|'s [=ViewTransition/named elements=], | ||
| and whose [=view transition params/initial snapshot containing block size=] is |transition|'s [=ViewTransition/initial snapshot containing block size=]. | ||
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| 1. [=Clear view transition=] |transition|. | ||
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| Note: The ViewTransition object on the old Document should be destroyed after its state has been copied to the new Document below. | ||
| We explicitly clear it here since the old Document may be cached by the UA. | ||
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| 1. Call |transition|'s [=outbound post-capture steps=] given |viewTransitionParams|. | ||
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Member
There was a problem hiding this comment. This needs to be done in a posted task because "Capture the old state" can be async. So we set "rendering suppression" to true, post a task which resets that bit and then invoke [=outbound post-capture steps=]. In that task, also check in case the phase for the transition is done (skip might have been called). The L1 spec does the same in the task posted here.
Collaborator
Author
There was a problem hiding this comment. The L1 spec in this case is a bit dodgy... posting a task doesn't guarantee anything wrt that async capture. We need to think about this further. |
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| ## Monkey patches to HTML ## {#monkey-patch-to-html} | ||
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| <div algorithm="monkey patch to apply the history step"> | ||
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@@ -558,7 +632,7 @@ When capturing the old or new state for an element, perform the following steps | |
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| <div algorithm> | ||
| To check if a <dfn export>navigation can trigger a cross-document view-transition?</dfn> given | ||
| an [=/origin=] |oldOrigin|, an [=/origin=] |newOrigin|, a boolean |navigationHasCrossOriginRedirects|, a {{NavigationType}} |navigationType|, and a boolean |isBrowserUINavigation|: | ||
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| Note: this is called during navigation, potentially [=in parallel=], for documents that have opted-in to view-transitions using the ''@view-transition'' rule. | ||
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@@ -577,7 +651,9 @@ When capturing the old or new state for an element, perform the following steps | |
| </div> | ||
| <div algorithm> | ||
| To <dfn export>setup cross-document view-transition</dfn> given a {{Document}} |oldDocument|, | ||
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| a {{Document}} |newDocument|, and |proceedWithNavigation|, which is an algorithm accepting nothing: | ||
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| 1. [=Assert=]: These steps are running as part of a [=task=] queued on |oldDocument|. | ||
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| 1. Let |resolvedRule| be the result of [=Resolve @view-transition rule|resolving the @view-transition rule=] for |oldDocument|. | ||
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@@ -593,54 +669,19 @@ When capturing the old or new state for an element, perform the following steps | |
| Note: this means that any running transition would be skipped when the document is ready | ||
| to unload. | ||
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| 1. Let |outboundTransition| be a new {{ViewTransition}} object in |oldDocument|'s [=relevant Realm=], | ||
| whose [=ViewTransition/active types=] is |resolvedRule|. | ||
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| 1. Set |outboundTransition|'s [=outbound post-capture steps=] to the following steps given a [=view transition params=]-or-null |params|: | ||
| 1. Set |newDocument|'s [=inbound view transition params=] to |params|. | ||
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| Note: The inbound transition is activated after the dispatch of {{Window/pagereveal}} to ensure mutations made in this event apply to the captured new state. | ||
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| 1. Call |proceedWithNavigation|. | ||
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Member
There was a problem hiding this comment. nit: Update the note below, "The process continues in [=perform pending transition operations=]." |
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| 1. Set |oldDocument|'s [=active view transition=] to |outboundTransition|. | ||
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| Note: The process continues in [=perform pending transition operations=]. | ||
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| 1. The user agent should display the currently displayed frame until either: | ||
| * The {{Window/pagereveal}} event is fired. | ||
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@@ -656,20 +697,38 @@ When capturing the old or new state for an element, perform the following steps | |
| <div algorithm> | ||
| To <dfn export>resolve cross-document view-transition</dfn> for {{Document}} |document|: | ||
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| 1. [=Assert=]: |document| is [=fully active=]. | ||
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| 1. Let |inboundViewTransitionParams| be |document|'s [=inbound view transition params=]. | ||
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| 1. If |inboundViewTransitionParams| is null, then return null. | ||
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| 1. Set |document|'s [=inbound view transition params=] to null. | ||
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| 1. If |document|'s [=active view transition=] is not null, then return null. | ||
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| Note: this means that starting a same-document transition before revealing the document would cancel a pending cross-document transition. | ||
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| 1. [=Resolve @view-transition rule=] for |document| and let |resolvedRule| be the result. | ||
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| 1. If |resolvedRule| is "<code>skip transition</code>", then return null. | ||
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| 1. Let |transition| be a new {{ViewTransition}} in |document|'s [=relevant Realm=], | ||
| whose [=ViewTransition/named elements=] is |inboundViewTransitionParams|'s [=view transition params/named elements=], | ||
| and [=ViewTransition/initial snapshot containing block size=] is |inboundViewTransitionParams|'s [=view transition params/initial snapshot containing block size=]. | ||
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| 1. Set |document|'s [=active view transition=] to |transition|. | ||
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| 1. [=Resolve=] |transition|’s [=ViewTransition/update callback done promise=] with undefined. | ||
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| 1. Set |transition|’s [=ViewTransition/phase=] to "`update-callback-called`". | ||
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| 1. Set |transition|'s [=ViewTransition/active types=] to |resolvedRule|. | ||
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| 1. At any given time, the UA may decide to skip the inbound transition, e.g. after an [=implementation-defined=] timeout. | ||
| To do so, the UA should [=queue a global task=] on the [=DOM manipulation task source=] given |document|'s [=relevant global object=] to perform the following step: | ||
| If |transition|'s [=ViewTransition/phase=] is not "`done`", then [=skip the view transition=] |transition| with a "{{TimeoutError}}" {{DOMException}}. | ||
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| 1. Return |transition|. | ||
| </div> | ||
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