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Re: Pundit and Open Annotation

From: Robert Sanderson <azaroth42@gmail.com>
Date: Fri, 23 Aug 2013 09:09:10 -0600
Message-ID: <CABevsUFw6AA+pFeObs620Xp+Gmb=-tEDkDiK_3AmeRU4PoeSOg@mail.gmail.com>
To: Christian Morbidoni <christian.morbidoni@gmail.com>
Cc: public-openannotation <public-openannotation@w3.org>
Hi Christian,

>> It's actually easier than that... the specifications of fragments for
>> HTML and XHTML don't allow XPointers.
> I see...so does it mean that if we in Pundit want a Xpointer based selector
> it shouldn't be a subclass of FragmentSelector? I think the RDF structure of
> the Fragment Selector fits well, but we could do the same just by not
> subclassing it...if it is more "formally" correct....

I don't think it should be a subclass of FragmentSelector as any
system that tried to treat it as a FragmentSelector would end up doing
the wrong thing.  Agreed that the structure fits well, so maybe just
duplicating it is the right way forwards?

Does anyone else have a requirement for a selector like this? It would
be good to pull together a list of non specification selectors that
people are using in practice.

>> >> -- SVG Selector
>> >> What is the position of OA with respect to percentage-based values?
>> The "position of Open Annotation" is neutral regarding percentages vs
>> absolute values.
>> However I agree that reuse on different, equivalent images is much
>> easier with percentages if those equivalencies are known. If you allow
>> for accurate percentages, can do the math for the layout, and know the
>> equivalencies, then percentages seem the right way to go.
> I'm not an SVG expert, but it seems to me there is at least no simple way in
> SVG to express percentages. I'm I wrong?
> In this case I guess Simone is likely to maintain the JSON based selector
> (our brand) that we are using at the moment. May be we could propose it as
> an extension to OA?

We could solve this issue with a slight wording change in the
specification to clarify what the SVG viewport means in SvgSelector.

If the viewport is "0 0 100 100" which should be scaled to the size of
the target image (with potentially different ratios for height and
width), then the coordinates in the SVG are essentially percentages.

Received on Friday, 23 August 2013 15:09:38 UTC

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