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[SVG Transforms 1.0, Part 2: Language (2009-03-20)] - Feedback for "4. 'animateTransform' Extensions"

From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Date: Sun, 22 Mar 2009 19:04:23 +0100
To: www-svg@w3.org
Message-Id: <200903221904.24018.Dr.O.Hoffmann@gmx.de>
Hello SVG WG,

mainly a suggestion for this section:

Consider the type matrix to be animatable too, this can
be pretty useful for some types of computed structures,
for example animated IFS (iterated function systems).
Authors today have to construct huge workarounds to
get a similar effect, because currently matrix is not
animatable.
For example one can workaround it with a huge values
animation of xlink:href of use referencing different 
static transformed pattern in the defs elements, 
about 20 pattern per second animation. This can be 
simply avoided, if matrix would be animatable.
In some versions of Opera this is available and
can be tested.

If matrix animation is implemented, this could (almost)
solve the current problem with a to animation
for animateTransform to meet the SMIL requirement
to have a smooth and continuous animation from
the underlying value to the to-value.
One simply can calculate the underlying value
and the to-value as matrices and to interpolate
between.
For some specific simple cases authors may expect
another behaviour (for example if the underlying
value is rotate(360) and the to value is rotate(0)),
but these simple cases can be typically covered
easily with from-to or values animations,
the typical SMIL effect, the basic functionality
for to-animations not.

Note, that skewX and skewY are mentioned here, but
not in section 3. Because there is no skewZ, this is
ok for section 3, for 4. however they can be skipped,
because the section title indicates, that it is 
only an extension. Whatever is done, I think, at
least 3. and 4, should be consistent and the titles
of the sections should fit to the content ;o)


Best wishes

Olaf
Received on Sunday, 22 March 2009 18:06:35 GMT

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