RE: svg and events

Hi Al.
> >My principles to date are:
> >
> >1. document order to match 'described' order,
> >i.e. logical progression from overview down to detail.
> 
> In general this cannot be done.  You have to use the 
> define/use cycle in SVG to first provide text in some 
> plausible narrative order and then reference the text in the 
> encoded drawing structure which is not a linear order but a 
> hierarchical scene graph.  It is not practical to try to 
> force the 'g' drawing group hierarchy into a narrative order. 
>  The prior declaration of the text in narrative order can be 
> in an embedded foreign object in XHTML Basic, for example.

OK, taking my defs as being 'data' or hash defines, substitute
use instead of actuals.

I think it is practical. I hope you can't prove me wrong.
The drawing order is only relevant in terms of what overlays
what, and (I think) that can be sorted.



> 
> >2. Each document entity to be wrapped in a g element,
> >   with min of desc and otionally both title and desc children.
> 
> That is to say each distinct scene object of enough 
> conceptual significance to be mentioned in the description.
> 
> Catch:  The 'g' drawing groups are part of the strict XML 
> hierarchy.  The conceptual objects one wishes to describe 
> form a general Venn diagram -- not a strict hierarchy.  There 
> are intersecting groups in the display that have both common 
> and distinguished sub-elements in them.  So some of the 
> notional elements may have to be documented as collections of 
> drawing groups, presumably via RDF in the 'meta' section.

Agreed, re-use will limit that. Simplistically any 'object'
will be within a group, though its children maybe uses of 
def'd content.


> The first navigation assistance to think about is 
> hierarchical, not linear.  
> 
> It is presumed that you can create a contents tree for the 
> display without too much mental sweat.  A possible 
> orientation technique is a one-level contents summary list in 
> the 'desc' element or in SVG attached to the 'g' structure 
> containing articulable substructure.  In any case, the way 
> you present the navigation hierarchy is by some emulation or 
> approximation of the DAISY book Table of Navigation and 
> associated navigation techniques.

Since I never 'describe' a figure in this way, I'd rather approach
it by providing a 'summary' / precis initially (This diagram shows... )
then go into the diagram. The missing elements will be the reader
commentary which says something like 'which is adjacent to the xxx'.

I want to avoid a 'special' nav table if possible, since it fits
unnaturally into a visual diagram.


> 
> A linear tour through the scene takes more mental effort, but 
> one has to think through the tour order before one can 
> consider tabbing through [the tour of] the scene. 

You got it. It takes practice to audio describe a diagram.


 This 
> depends on the author's understanding of the story that the 
> scene has to tell.  It is not recognizable in the XML 
> hierarchy without additional help from some human.  

(or the diagram author ;-)


> >Issues:
> >	How to present the navigation method to the listner?

I know what to say, its how to say it / present it to 
someone opening the diagram. Its the equivalent of having instructions
to open a parcel inside the parcel !


Regards DaveP
(Also a volunteer reader for 5 years).


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Received on Wednesday, 13 March 2002 02:55:45 UTC