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Re: 15.1.2 Navigation

From: Peter Sorotokin <psorotok@adobe.com>
Date: Thu, 11 Nov 2004 13:57:15 -0800
To: Doug Schepers <doug@schepers.cc>, www-svg@w3.org
Message-id: <5.2.0.9.2.20041111135554.0369d830@mailsj-v1.corp.adobe.com>

At 06:00 AM 11/11/2004 -0500, Doug Schepers wrote:

>Hi-
>
>Directional navigation seems a little confusing. Am I understanding it
>correctly to say that nav-up, nav-down, nav-left, and nav-right depend on
>the document order? Is there no other way to specify the order? If I
>misunderstand this, forgive me.
>
>I appreciate that this is a property inherited from CSS, but CSS had HTML as
>its use case, which is a document format in which elements and text defined
>at the beginning of the document most typically will be visually depicted at
>the top of the page, and in which the document and location order of those
>elements rarely changes. This is far from the case with SVG.
>
>Consider:
><svg>
>   <circle id="c1" focusable="true" cx="300" cy="500" ... />
>   <rect id="r1" focusable="true" x="100" y="100" ... />
>   <circle id="c2" focusable="true" cx="50" cy="50" ... />
></svg>
>
>If the current focus were on Rectangle 'r1', and the user pressed the up
>arrow key, triggering a nav-up event, the focus would shift to Circle 'c1',
>which is earlier in the document order but "down" in the visual field. This
>is compounded by the fact that often elements are repositioned dynamically,
>making the authoring of a document that has consistent behavior regards
>directional navigation via document order vs. visual location impossible.
>
>This would be completely unintuitive to the user. I *strongly* suggest that
>the SVG WG reconsider the use cases for this feature and its behavior. My
>suggestion is that nav-[direction] operate on the visual location, not the
>document order. I think that this should be the default, if not only,
>attribute value.

Do you have specific algorithm in mind? How would you determine what the 
visual order is in SVG? It seems that it would be very fragile.

Peter


>I have use cases and demos if you are interested.
>
>
>Regards-
>-Doug
Received on Thursday, 11 November 2004 21:57:22 UTC

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