Open Bug 1273834 Opened 7 years ago Updated 2 months ago

getComputedStyle().transform/opacity should return style values updated by TimeStamp::Now() instead of the most recent refresh time on busy frame.


(Core :: CSS Parsing and Computation, defect)




Tracking Status
firefox49 --- affected


(Reporter: hiro, Unassigned)




(1 file)

Attached file An example
This bug is related to bug 1167519.

getComputedStyle() flushes styles but it's against the most recent refresh time.  If getComputedStyle() is called for styles on the compositor animations in a busy frame, we will get a different value from what we are seeing the animation on the compositor.

From CSS transition spec:

> Therefore if a script queries the computed style of a property as it is transitioning,
> it will see an intermediate value that represents the current animated value of the property

Attaching file is a modification of attachment 8610350 [details] in bug 1167519.
On Chrome getComputedStyle().transform in the file returns a value close to 230, but we don't.
I'm not quite sure I understand what this bug covers that bug 1167519 does not -- perhaps it is about the time in between triggering the new transition and when we update the 'from' keyframe?
Severity: normal → S3
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