- From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
- Date: Sat, 1 Jul 2006 14:25:21 +0200
- To: www-smil@w3.org
Hello, I tried to find something about a to-animation (without) from for a non-additive attribute, but I could not find much about it. If it is mentioned, it would be already helpful to know in which section. But as far as I have seen, this is not completely clear from the recommendation what to do with this. Old recommendation 04-September-2001 notes about to-animation in general: 'This describes an animation in which the animation function is defined to start with the underlying value for the attribute, and finish with the value specified with the to attribute. Using this form, an author can describe an animation that will start with any current value for the attribute, and will end up at the desired to value. The last two forms "by animation" and "to animation" have additional semantic constraints when combined with other animations. The details of this are described below in the section How from, to and by attributes affect additive behavior. ' This is already sufficient if there is no lower priority animation, even for non-additive attributes or properties. Anyway it is not mentioned, what happens if the behaviour cannot be additive sum, but has to be replace in the case with a lower priority animation. Is it correct, that in this case the to-animation will replace all lower priority animations, just starting with the underlying value directly from the animated attribute too? This would be one possible interpretation of this paragraph concerning non-additve attributes or properties. The other one is: If c(begin) is the current (time dependent) underlying value from lower priority animations at the begin of the higer priority to-animation, and f is the final value given by the to-animation, this is the same visual effect as using values="c(begin); f". Which interpretation is correct or what is the correct behaviour if none of them is correct? Even if this is clearified for SVG1.0 and SVG1.1 using the old recommendation, SMIL2.1 changes description: ' This describes an animation in which the animation function is defined to start with the underlying value for the attribute, and finish with the value specified with the to attribute. Using this form, an author can describe an animation that will start with any current value for the attribute, and will end up at the desired to value. A normative definition of a to animation is given below in To animation ' Well, the first part is the same but seems to be changed to something just informative, not normative, but the second refers to a section defining only the behaviour of additive attributes and properties. Therefore correct behaviour of non-additive attributes seems to be completely undefined, even if there is no lower priority animation. Therefore: Is it intended to change the previously defined behaviour? Which behaviour is correct in these cases with SMIL2.1? For example in SVG there is the attribute 'rotate' of the 'text' element defined to be non-additive and the property 'stroke-dasharray'. If we take this as an example: <text x="200" y="400" rotate="-30" stroke="#ccc">? <animate attributeName="rotate" attributeType="XML" to="30" dur="3s" /> </text> Is this the same visual effect as using: 1. values="-30;30" or 2. values="30" or instead of animate <set attributeName="rotate" attributeType="XML" to="30" dur="5s" /> or 3. values="-30;30" calcMode="discrete" or 4. authors should not use to-animations for non-additive attributes or properties, viewers should ignore an animation like this. or 5. something different? Is it correct in a general case to assume, that the animation of highest priority will overwrite other animations in this case, that therefore the chosen alternative from 1. to 5. is always applicable for the animation with highest priority? Or is the replacement values="c(begin); f" as mentioned above the correct general interpretation? A related question: If fill is freeze, the general rule for none-additive attributes is applied and not the special rule for frozen to-animations? Grateful for any information about this Olaf Hoffmann
Received on Saturday, 1 July 2006 12:24:33 UTC