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Are override stylesheets for SMIL animations underspecified?

From: Vincent Hardy <vhardy@adobe.com>
Date: Wed, 4 Jan 2012 10:10:29 -0800
To: "public-fx@w3.org" <public-fx@w3.org>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <CB29D615.29804%vhardy@adobe.com>

During today's CSS WG teleconference, there was a discussion about where animations fit into the CSS cascade, and it was pointed out that SMIL animations use the CSS override style:


During the discussion, the CSS Working group resolved the following:

RESOLVED: Allow user !important rules to override animations (exact location of animations in the cascade level still undetermined)
RESOLVED: Define the override level of specificity somewhere, and decide where animations go in relation to it.

Since this discussion has a direct relation to the work done in SVG / SMIL animations, I took the action to send this notification email.

For reference, the SVG 1.1 2nd edition still references the SMIL Animation specification (http://www.w3.org/TR/2001/REC-smil-animation-20010904/), which says the following:

In CSS2 and the DOM 2 CSS-OM, the terms "specified", "computed" and "actual" are used to describe the results of evaluating the syntax, the cascade and the presentation rendering. When animation is applied to CSS properties of a particular element, the base value to be animated is read using the (readonly) getComputedStyle() method on that element. The values produced by the animation are written into an override stylesheet for that element, which may be obtained using the getOverrideStyle() method. These new values then affect the cascade and are reflected in a new computed value (and thus, modified presentation). This means that the effect of animation overrides all style sheet rules, except for user rules with the !important property. This enables !importantuser style settings to have priority over animations, an important requirement for accessibility. Note that the animation may have side effects upon the document layout. See also the [CSS2<http://www.w3.org/TR/2001/REC-smil-animation-20010904/#ref-CSS2>] specification (the terms are defined in section 6.1), and the [DOM2CSS<http://www.w3.org/TR/2001/REC-smil-animation-20010904/#ref-DOM-CSS>] specification (section 5.2.1).

Received on Wednesday, 4 January 2012 18:11:27 UTC

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