From e10250e55830c3e39054e61e90d6c8905064f06b Mon Sep 17 00:00:00 2001 From: Florian Rivoal Date: Thu, 12 Mar 2026 22:54:46 +0900 Subject: [PATCH 1/2] [css-image-animation] Define what state 'running' starts from This is in response to https://github.com/w3c/csswg-drafts/issues/13429. --- css-image-animation-1/Overview.bs | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/css-image-animation-1/Overview.bs b/css-image-animation-1/Overview.bs index bdca19fb90bc..152821a93dc2 100644 --- a/css-image-animation-1/Overview.bs +++ b/css-image-animation-1/Overview.bs @@ -132,7 +132,7 @@ Controlling Image Animations: the 'image-animation' property {#image-animation}
Like ''normal'', the animation of [=animated images=] is run normally, - as determined by the image format and the host language, + as determined by the image format and the host language. However, animation timelines are scoped per element: @@ -141,8 +141,15 @@ Controlling Image Animations: the 'image-animation' property {#image-animation} the same image data, and with an 'image-animation' computed value of ''running'' must be rendered synchronized to the same timeline as a group, - distinct from the timeline of images in other elements, - with the timeline starting at the time of the least recent addition to the group. + distinct from the timeline of images in other elements. + + If images are added to the element while the computed value is ''running'', + the timeline starts at the time of the least recent addition to the group. + + If this property is switched to ''running'' from another value, + the beginnig of this timeline is set + so that the animation continues from the state that was displayed + at the timem of the switch.
From 0c9466a2d53c7e03f05dda69fbf987cd59ebeb7b Mon Sep 17 00:00:00 2001 From: Florian Rivoal Date: Mon, 16 Mar 2026 18:58:35 +0900 Subject: [PATCH 2/2] Clarify what happens with new elements and display:none --- css-image-animation-1/Overview.bs | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/css-image-animation-1/Overview.bs b/css-image-animation-1/Overview.bs index 152821a93dc2..ae3bad1b7829 100644 --- a/css-image-animation-1/Overview.bs +++ b/css-image-animation-1/Overview.bs @@ -146,6 +146,10 @@ Controlling Image Animations: the 'image-animation' property {#image-animation} If images are added to the element while the computed value is ''running'', the timeline starts at the time of the least recent addition to the group. + If the element is created or made visible after having previously been set to ''display: none'', + with images already added and with 'image-animation' already set to ''running'', + the timeline starts when the element is included in the layout. + If this property is switched to ''running'' from another value, the beginnig of this timeline is set so that the animation continues from the state that was displayed