Re: [SMIL30 LC comment] 3.4 and 3.6

 Dear Dr. Olaf Hoffmann ,

The SYMM Working Group has reviewed the comments you sent [1] on the Last
Call Working Draft [2] of the Synchronized Multimedia Integration Language
(SMIL 3.0) published on 13 Jul 2007. Thank you for having taken the time to
review the document and to send us comments!

The Working Group's response to your comment is included below.

Please review it carefully and let us know by email at www-smil@w3.org if
you agree with it or not before 02 nov 2007. In case of disagreement, you
are requested to provide a specific solution for or a path to a consensus
with the Working Group. If such a consensus cannot be achieved, you will
be given the opportunity to raise a formal objection which will then be
reviewed by the Director during the transition of this document to the
next stage in the W3C Recommendation Track.

Thanks,

For the SYMM Working Group,
Thierry Michel
W3C Staff Contact

 1. http://www.w3.org/mid/200708171735.07637.Dr.O.Hoffmann@gmx.de
 2. http://www.w3.org/TR/2007/WD-SMIL3-20070713/


=====

Your comment on 3.4 Animation Model:
> Hello SMIL working group,
> 
> 
> some comments related to the chapters
> 3.4 and 3.6:
> 
> 
> 3.4.1 The simple animation function f(t)
> 
> 
> 'The animation function is a function of the current position, as well
> 
> as of time:
> f(t,u) = (u*(2.5s-t)/2.5s) + 10*(t/2.5s)'
> 
> -> u is undefined at this text position.
> Better:
> 'The animation function f is a function of the current position u(t), 
> as well as of time
> t (here given in seconds):
> f(t,u(t)) = (u(t)*(2.5s-t)/2.5s) + 10*(t/2.5s)'
> 
> Alternatively it would be useful too to define often used symbols at
> the 
> top of the animation chapter.
> This is done in 3.4.2, but this is too late for this section, this
> indicates
> a bad document structure...
> 
> ------------------
> 
> 'The simple animation function defined by an animation element is a 
> function of time, 
> f(t), defined for times t, 0<=t<=d, where d is the simple duration of
> the 
> element.'
> 
> -> define or reference definition of 'simple duration'
> 
> ------------------
> 
> 'The animation effect function, F(t,u), of an animation element with 
> active duration AD ...'
> 
> -> define or reference definition of 'active duration'
> 
> --------------------
> 
> 
> '3.4.2 Summary of symbols used in the semantic descriptions
> 
> This section is informative.'
> 
> -> The symbols are used in normative parts, how can this be
> informative?
> How can the normative parts be understandable with only informative
> defined
> symbols? ;o)
> 
> -> reference definitions of  'simple duration', 'active duration' ...
> 
> -------------------
> '3.4.3 The animation sandwich model
> 
> This section is informative.'
> 
> This was not indicated as informative in SMIL2 - sure, that this is 
> informative?
> It contains  (!)important (?) information about priorities of
> animations.
> And if it is informative, what about this in a normative part of
> 3.4.1:
> 'This is detailed in The animation sandwich model.'
> If the section is only informative and not normative, it cannot
> contain
> any information relevant for a normative part?
> 
> --------------------
> 
> 'Specifically, animating an attribute defined in XML will modify the 
> presentation 
> value before it is passed through the style sheet cascade, using the
> XML DOM 
> value as its base. Animating an attribute defined in a style sheet
> language
> will modify the presentation value passed through the remainder of the
> cascade.'
> 
> -> For example the style sheet language CSS has properties and no
> attributes, what about them? 
> Does XSL have attributes (I think, it has mainly formatting objects
> and
> properties)? Which style sheet language defines attributes?
> Better:
> 'Animating an attribute or property defined in a style sheet language
> will 
> modify the 
> presentation value passed through the remainder of the cascade.'?
> or if there are no attributes in style sheet languages:
> Animating a property defined in a style sheet language will modify the
> 
> presentation value passed through the remainder of the cascade.'?
> 
> -> If we take as an example a basic shape from SVG, for them
> presentational 
> XML attributes and CSS properties exist with the same meaning and the
> same name, for example the property/attribute fill. If we use
> attributeType XML and CSS we can distinguish between them.
> This paragraph means that the animation using attributeType XML is
> applied before it is passed through the style sheet cascade, while
> with attributeType CSS (or auto) it is applied to the remainder of the
> cascacde. Is this correct? This means animations using attributeType
> XML
> are overwritten for example by external author style sheets, because 
> those are later in the style sheet cascade. But using attributeType
> CSS
> means, the animation superseedes the style sheets again (if there is
> no
> !important from a user style sheet). Is this correct?
>  
> ------------------------------
> 3.4.5 The animation effect function F(t,u)
> 
> 
> typo?
> 
> 'The effect of the animation is to to just use the value for f(0),
> setting 
> the fill color to red for the remainder of the animate element's
> duration.'
> ->
> 'The effect of the animation is just to use the value for f(0), setting
> the
> fill color to red for the remainder of the animate element's
> duration.'?
> 
> 
> ---------------------
> 
> 'For example, the path notation for a simple arc (detailed in 
> The animateMotion element) 
> can be used to describe a bouncing motion:
> 
> <img ...>
>    <animateMotion path="m 0 0 c 30 50 70 50 100 0 z" dur="5s"
>       accumulate="sum" repeatCount="4" />
> </img>'
> 
> -> Note that this example is in the BasicAnimation module and
> references
> animateMotion from the BasicAnimation module but the path attribute is
> 
> from the SplineAnimation module. This might confuse a little bit and
> is not very comfortable for readers, if they really want to understand
> this. 
> -> minimal improvement would be a reference from the 'path notation'
> to
> the related section of the SplineAnimation module and a note, that for
> this example the SplineAnimation module is required...
> 
> 
> 
> 
> --------------------
> 3.4.6 Additive animation
> 
> 'An element may be defined as additive only if addition is 
>  defined for the type of the target attribute.'
> 
> -> What happens, if this is not explicitely specified for the 
> target attribute? No animation at all?
> 
> -------------------
> 
> '  This section is informative.
> 
> When there are multiple animations defined for a given attribute that
> overlap 
> at any moment, the two either add together or one overrides the
> other...'
> 
> -> Sure that this is only informative? In SMIL2 it was not indicated as
> 
> informative 
> and contains important (?) information on priorities and about the
> question, 
> for 
> which types of attributes additive animation may be defined...   
> 
>  -------------------
> 
> '<img top="10" ... >
>   <animate dur="10s" repeatDur="indefinite"
> 
>            attributename="top" from="20" by="10"
> 
>            additive="sum" accumulate="sum" />
> </img>
> 
> The animation adds to the original value of 10 that was set for "top",
> 
> and begins at the value 30. It moves down by 10 pixels to 40, then
> repeats. 
> It is cumulative, so the second iteration starts at 60 (the value of 40
> from
> the previous iteration plus 20) and moves down by another 10 to 70, and
> 
> so on.'
> 
> -> better:
> '... (the value of 30 from the previous iteration plus 20 from the
> from
> attribute and plus 10 from the underlying value) ...'
> 
> This is not important in this situation, but for attributes with not
> commutable addition the order of the additions is important 
> (for example SVG has such attributes), therefore it is important to 
> pronounce that 60 results from three additions with numbers from 
> three different sources...
> 
> 
> 
> ------------------------
> 
> 3.6.2 Specifying the simple animation function f(t)
> 
> 
> - What is recommended for calcMode paced, if there is
> a known procedure to produce an even pace of change 
> across the animation, but this procedure does not interpolate
> between the values? This happens for example for a list
> of numbers or coordinates as animated values.
> Such lists are no vectors, sometimes lists of vectors.
> Fallback to linear? 
> A SMIL3 example is the new viewBox, as already commented.


Working Group Resolution:
Dr. Olaf Hoffmann wrote:
> Hello SMIL working group,
> 
> 
> some comments related to the chapters
> 3.4 and 3.6:
> 
> 
> 3.4.1 The simple animation function f(t)
> 
> 
> 'The animation function is a function of the current position, as well 
> as of time:
> f(t,u) = (u*(2.5s-t)/2.5s) + 10*(t/2.5s)'
> 
> -> u is undefined at this text position.
> Better:
> 'The animation function f is a function of the current position u(t), 
> as well as of time
> t (here given in seconds):
> f(t,u(t)) = (u(t)*(2.5s-t)/2.5s) + 10*(t/2.5s)'
> 
> Alternatively it would be useful too to define often used symbols at the

> top of the animation chapter.
> This is done in 3.4.2, but this is too late for this section, this
indicates
> a bad document structure...

Moved the section Summary of symbols used in the semantic descriptions
to before the section The simple animation function f(t).  This should
help with the symbol u not being defined at this point yet.
Also interchanged the actual normative definition of the underlying
value u and the animation effect function F(t,u).

> ------------------
> 
> 'The simple animation function defined by an animation element is a 
> function of time, 
> f(t), defined for times t, 0<=t<=d, where d is the simple duration of
the 
> element.'
> 
> -> define or reference definition of 'simple duration'
> 
> ------------------
> 
> 'The animation effect function, F(t,u), of an animation element with 
> active duration AD ...'
> 
> -> define or reference definition of 'active duration'

Made the terms "simple duration" and "active duration" links to the
appropriate sections in the Timing & Synchronization chapter.  This was
done only in the summary of symbols section and in the normative block
where d and AD are first defined.

> --------------------
> 
> 
> '3.4.2 Summary of symbols used in the semantic descriptions
> 
> This section is informative.'
> 
> -> The symbols are used in normative parts, how can this be
informative?
> How can the normative parts be understandable with only informative
defined
> symbols? ;o)
> 
> -> reference definitions of  'simple duration', 'active duration' ...

See above.

> -------------------
> '3.4.3 The animation sandwich model
> 
> This section is informative.'
> 
> This was not indicated as informative in SMIL2 - sure, that this is 
> informative?
> It contains  (!)important (?) information about priorities of
animations.
> And if it is informative, what about this in a normative part of 3.4.1:
> 'This is detailed in The animation sandwich model.'
> If the section is only informative and not normative, it cannot contain
> any information relevant for a normative part?

When adding normative/informative markup to this chapter, we
accidentally marked this as informative.

> --------------------
> 
> 'Specifically, animating an attribute defined in XML will modify the 
> presentation 
> value before it is passed through the style sheet cascade, using the XML
DOM 
> value as its base. Animating an attribute defined in a style sheet
language
> will modify the presentation value passed through the remainder of the
> cascade.'
> 
> -> For example the style sheet language CSS has properties and no
> attributes, what about them? 
> Does XSL have attributes (I think, it has mainly formatting objects and
> properties)? Which style sheet language defines attributes?
> Better:
> 'Animating an attribute or property defined in a style sheet language
will 
> modify the 
> presentation value passed through the remainder of the cascade.'?
> or if there are no attributes in style sheet languages:
> Animating a property defined in a style sheet language will modify the 
> presentation value passed through the remainder of the cascade.'?

Added "or property".

> -> If we take as an example a basic shape from SVG, for them
presentational 
> XML attributes and CSS properties exist with the same meaning and the
> same name, for example the property/attribute fill. If we use
> attributeType XML and CSS we can distinguish between them.
> This paragraph means that the animation using attributeType XML is
> applied before it is passed through the style sheet cascade, while
> with attributeType CSS (or auto) it is applied to the remainder of the
> cascacde. Is this correct? This means animations using attributeType
XML
> are overwritten for example by external author style sheets, because 
> those are later in the style sheet cascade. But using attributeType CSS
> means, the animation superseedes the style sheets again (if there is no
> !important from a user style sheet). Is this correct?

You are correct on both counts here.

> ------------------------------
> 3.4.5 The animation effect function F(t,u)
> 
> 
> typo?
> 
> 'The effect of the animation is to to just use the value for f(0),
setting 
> the fill color to red for the remainder of the animate element's
duration.'
> ->
> 'The effect of the animation is just to use the value for f(0), setting
the
> fill color to red for the remainder of the animate element's
duration.'?

Fixed.

> ---------------------
> 
> 'For example, the path notation for a simple arc (detailed in 
> The animateMotion element) 
> can be used to describe a bouncing motion:
> 
> <img ...>
>    <animateMotion path="m 0 0 c 30 50 70 50 100 0 z" dur="5s"
>       accumulate="sum" repeatCount="4" />
> </img>'
> 
> -> Note that this example is in the BasicAnimation module and
references
> animateMotion from the BasicAnimation module but the path attribute is 
> from the SplineAnimation module. This might confuse a little bit and
> is not very comfortable for readers, if they really want to understand
> this. 
> -> minimal improvement would be a reference from the 'path notation' to
> the related section of the SplineAnimation module and a note, that for
> this example the SplineAnimation module is required...

Changed the reference from "The animateMotion element" to "The spline
animateMotion element".  Also changed the styling of the word "path" so
that it is a link to the definition of the attribute.

> --------------------
> 3.4.6 Additive animation
> 
> 'An element may be defined as additive only if addition is 
>  defined for the type of the target attribute.'
> 
> -> What happens, if this is not explicitely specified for the 
> target attribute? No animation at all?

This is a requirement for the author of a SMIL profile.  If this is not
done, the profile is erroneous.  The spec can and should not assume that
such a thing can happen.

> -------------------
> 
> '  This section is informative.
> 
> When there are multiple animations defined for a given attribute that
overlap 
> at any moment, the two either add together or one overrides the
other...'
> 
> -> Sure that this is only informative? In SMIL2 it was not indicated as

> informative 
> and contains important (?) information on priorities and about the
question, 
> for 
> which types of attributes additive animation may be defined...   

Since the section The sandwich model is now normative, this paragraph
can remain informative.

>  -------------------
> 
> '<img top="10" ... >
>   <animate dur="10s" repeatDur="indefinite"
> 
>            attributename="top" from="20" by="10"
> 
>            additive="sum" accumulate="sum" />
> </img>
> 
> The animation adds to the original value of 10 that was set for "top", 
> and begins at the value 30. It moves down by 10 pixels to 40, then
repeats. 
> It is cumulative, so the second iteration starts at 60 (the value of 40
from
> the previous iteration plus 20) and moves down by another 10 to 70, and

> so on.'
> 
> -> better:
> '... (the value of 30 from the previous iteration plus 20 from the from
> attribute and plus 10 from the underlying value) ...'
> 
> This is not important in this situation, but for attributes with not
> commutable addition the order of the additions is important 
> (for example SVG has such attributes), therefore it is important to 
> pronounce that 60 results from three additions with numbers from 
> three different sources...

Done as suggested.

> ------------------------
> 
> 3.6.2 Specifying the simple animation function f(t)
> 
> 
> - What is recommended for calcMode paced, if there is
> a known procedure to produce an even pace of change 
> across the animation, but this procedure does not interpolate
> between the values? This happens for example for a list
> of numbers or coordinates as animated values.
> Such lists are no vectors, sometimes lists of vectors.
> Fallback to linear? 
> A SMIL3 example is the new viewBox, as already commented.

There is already a restriction in place which says that it must be
possible to calculate a "distance" between points.  Isn't this
restriction enough?  We have a hard time envisioning a distance function
between e.g. viewBox values, but if it is possible, then this distance
can be used.


----

Received on Tuesday, 23 October 2007 09:08:30 UTC