- From: David Vest <davve@opera.com>
- Date: Thu, 08 Feb 2007 17:40:43 +0100
- To: www-svg <www-svg@w3.org>
Hello WG and all! My issue is related to animateTransform and the directive in SVG 1.2 Tiny 1.2 that says: "If 'from' or 'to' attributes are not specified, the underlying value (see SMIL discussion of animation function values) is the corresponding identity transformation value." [1] this, in combination with "To animations" [2] in SMIL that says: "To animation defines its own kind of additive semantics, so the additive attribute is ignored." These two statements makes it impossible for animateTransforms without a 'from'-value to be additive. I wonder if this is the intended behaviour. This is an example that should show no red, if both these statements are fulfilled: <?xml version="1.0" encoding="iso-8859-1" ?> <svg width="500px" height="500px" viewBox="-250 -250 500 500" xmlns="http://www.w3.org/2000/svg" version="1.1" baseProfile="tiny" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>animateTransform, 'to'-animations and additiveness</title> <circle id="c5" cx="0" cy="0" r="40" fill="grey"/> <circle id="c5" cx="-100" cy="0" r="40" fill="grey"/> <circle id="c5" cx="100" cy="0" r="40" fill="grey"/> <circle id="c2" cx="0" cy="0" r="30" fill="red" transform="translate(-100,0)"> <animateTransform attributeName="transform" attributeType="XML" type="translate" to="100,0" dur="3s" begin="0s" fill="freeze" additive="sum"/> </circle> <circle id="c2" cx="0" cy="0" r="30" fill="green" transform="translate(-100,0)"> <animateTransform attributeName="transform" attributeType="XML" type="translate" to="100,0" dur="3s" begin="0s" fill="freeze" /> </circle> </svg> I see three different options here: 1. Accept the current situation. It makes 'to'-animations with animateTransform silly, since they can't be additive and therefore not very useful. 2. Add an override statement to SVG that respects additive="sum" for animateTransforms without 'from', since the underlying value (implicit 'from'-value) is the identity matrix. 3. Change the wording how the underlying value is extracted. This is a bit complex since the 'real' underlying value is a list of transforms, but perhaps one could allow lists of length one as a underlying value (use the one transform in the list). (4. I have gotten this all wrong and someone will correct me and send me along my merry way...) By searching the list (www-svg) I find that Dr. Hoffman has brought up this before [3] (I think, his mail touches upon other points too). Also, Cameron McCormack has raised questions about how to-animations should work in animateTransform[4]. [1] http://www.w3.org/TR/SVGMobile12/animate.html#AnimateTransformElement [2] http://www.w3.org/TR/2005/REC-SMIL2-20051213/animation.html#animationNS-ToAnimation [3] http://lists.w3.org/Archives/Public/www-svg/2006May/0132 [4] http://lists.w3.org/Archives/Public/www-svg/2006Jul/0020 -- David Vest <davve@opera.com>
Received on Thursday, 8 February 2007 16:40:59 UTC