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Re: SVG12: animation of <color> and <paint>

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Sat, 31 Dec 2005 22:51:49 +0100
To: Chris Lilley <chris@w3.org>
Cc: www-svg@w3.org
Message-ID: <d4pdr15iocv1232jd2kt7tvng7imhf8fmp@hive.bjoern.hoehrmann.de>

* Chris Lilley wrote:
>The specification has been clarified to say that it is the computed
>value of a property that is animated.
>Consider the following example
><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 340 120"
>baseProfile="Tiny" version="1.2">

(it's "tiny", not "Tiny", btw)

>  <title>test animateColor with keywords</title>
>  <rect color="green" fill="#000000" height="100" width="100">
>    <animateColor attributeName="fill"
>                  from="#f00" to="currentColor"
>                  begin="1s" dur="5s" fill="freeze" />
>  </rect>

This example is not relevant to this issue, it is relevant to my other
issue, <http://lists.w3.org/Archives/Public/www-svg/2005Dec/0137.html>.
We have two value spaces

  +---------------+                      +-----------------------------+
  | Lexical Space |                      | n-dim numerical value space |
  +---------------+                      +-----------------------------+
  | white         | --convert1(value)--> | ???                         |
  | #fff          | --convert2(value)--> | (255,255,255)               |
  | butt          | --convert3(value)--> |                             |
  | currentColor  | --convert4(value)--> | ??? (different issue)       |
  +---------------+                      +-----------------------------+

This issue is concerned with the convert1() function as "white" is a
keyword for which the draft defines how to translate it directly into
the n-dimensional numerical value space.

It is not concerned with the convert2() function as "#fff" is not a
keyword, it is not concerned with the convert3() function as the draft
is clear that no such function is defined, and it is not concerned with
convert4() as such a function cannot exist (it'd require more input
parameters); convert4() is the other issue cited above.

My concern is that the draft notes in passing that keywords are not
additive; the addition of the term "computed value" to this note is
irrelevant to my concern as for fill="white" the computed value is
the specified value "white" which is still a keyword.

I want the draft to be clear for which attribute/property values such a
conversion function is defined and when two results of such a function
are compatible, and that whenever two well-defined compatible results
are specified, the animation is allowed and support for it required.

If your example above is not prohibed, I've explained in detail what
the draft would need to define in addition in the message cited above.

I should add that the changes made here actually make the draft more
confusing than before, e.g. the note for <color> "Only additive if the
computed value is a color." makes no sense at all as the computed value
cannot possibly be something but a "color". For <paint> the confusing
note "Only RGB color values are additive." is still there. And so on.
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
Weinh. Str. 22 · Telefon: +49(0)621/4309674 · http://www.bjoernsworld.de
68309 Mannheim · PGP Pub. KeyID: 0xA4357E78 · http://www.websitedev.de/ 
Received on Saturday, 31 December 2005 21:51:31 UTC

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