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Re: [css3-transforms] 7.2. Syntax of the SVG ‘transform’ attribute

From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Date: Sat, 21 Apr 2012 16:37:32 +0100
To: www-style@w3.org, public-fx@w3.org
Message-Id: <201204211737.32381.Dr.O.Hoffmann@gmx.de>
Dirk Schulze:

>
> This specification wants to provide backwards compatibility to SVG 1.1, not
> to older viewers. If we consider that new content must work on older
> Viewers, we can't include any new feature at all.
>

It is backwards compatibility to SVG 1.1, because this does only allow
numbers without units, what is in general a good idea for SVG.
Obviously this matters for SVG1.1 viewers, old or new.
In general this sections seems to be more related to CSS compatibility,
not to backwards compatibility to SVG 1.1, because it introduces new 
syntax, not really needed for the SVG attribute.
Why not so skip units completely for the attribute as it applies already now?
For example (X)HTML has no such unit letters 'px' as well - why to care 
about it in SVG and not in (X)HTML, where it would be much more useful
than in SVG to have units like em, ex availlable, not just % and implied px?
 
The syntax for the transform property in this draft  is not compatible anyway 
with the SVG1.1 transform attribute and units not useful for the attribute.
Why to care, why to change this - just to please the CSS working group
with superflous unit-letters and to annoy authors and the audience with
failing documents, just because this new draft contains misleading
and manipulative hints for authors of SVG documents, far away from best
practice?

And of course, it is possible with advanced fallback mechanisms to
introduce new features in a backwards compatible way.
But if such a draft forces authors to use more complicated
new syntax for features, they can be already realised with simpler
old syntax, this undermines such a possible fallback mechanism -
therefore bad idea, change as suggested or better remove the
entire unit thing from the section related to the attribute to avoid
the complete problem.

Another option is of course to allow an incompatible unit extension,
but to remove any suggestion to authors on the question of units,
adding only a hint, that in previous SVG versions up to SVG 1.1.1 and
SVG tiny 1.2 (this means currently all SVG versions) units are dissallowed.


Olaf
Received on Saturday, 21 April 2012 15:38:01 GMT

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