Re: WebCGM preview

[Dieter@isodraw.de (Dieter Weidenbrueck)]

Lofton,

good answer. Obviously I looked at 3.2.1.1 only.

Comments:

1. The wording is a bit confusing:
For an object that has a view_context attribute
- 3.1.2.3 suggests both navigation AND highlight plus a default behavior
(highlight)
- 3.2.1.1 suggests navigation only
This should be made consistent.

The combined navigation and highlighting of course only works if there is a
body, i.e. if graphical primitives exist.
Also the last sentence of the view_context para should read
"The view_context behavior is the default behavior."
The current language is probably misleading with regard to the highlight
statement right before the "This is...".

It becomes obvious that the viewer behavior leaves a lot of room for
interpretation. The requirement "... moves the object into view" for example
is met in your example, because a shrink-to-fit representation does of
course show the object. However, this example really doesn't show the
difference between highlight and view_context.
IsoView will move the object into view and zoom into the illustration so
that the object becomes the dominant part in the viewer rectangle.

BTW, we recently decided to use lowercase for all attributes/tag names.
Throughout the spec almost all possible variants of "view_context",
"linkuri" etc are used. Will we adjust the spelling in the spec to lowercase
as well?

Dieter

----- Original Message -----
From: "Lofton Henderson" <lofton@rockynet.com>
To: "Dieter" <dieter@itedo.com>; <cgmopen-members@lists.oasis-open.org>
Sent: Tuesday, May 29, 2001 4:31 PM
Subject: Re: WebCGM preview


> At 04:51 PM 5/28/01 +0200, Dieter Weidenbrueck wrote:
> >Lofton,
> >
> >some quick comments:
> >
> >linking-selectId-BE-05
> >The PNG image shows "myObject" selected. However, a URL like
> >xxx.cgm#myObject would trigger default object behavior, which is
> >view_context and no highlight.
>
> This is not the way I read the standard.  From 3.1.2.3, "Object Selection
> Keywords":
>
> ### begin excerpt ###
> view_context - If a 'ViewContext' attribute exists for the object APS,
> display only the rectangular region of the picture defined in the
> ViewContext attribute, and highlight the object. If no ViewContext
> attribute exists in the object, the highlight behavior shall be
> implemented. This is the default behavior.
>
> highlight - highlight the first object selected and ignore the ViewContext
> attribute, if present. The resulting view is a full-picture view, not a
> zoomed view.
>
> highlight_all - highlight all objects selected. The resulting view is a
> full-picture view, not a zoomed view.
> ### end excerpt ###
>
> First, under view_context, note that behavior defaults to "highlight", if
> there is no 'viewcontext' APS attribute on the object.
>
> Next, from 3.2.1.1:
>
> ### begin excerpt ###
> * If the object contains a view context attribute, the viewer shall "fit"
> the view context into the viewer's display rectangle and create a new
> display inside this rectangle.
> * If the object does not contain a "view context" attribute, but contains
a
> "region" attribute, the viewer shall move the object into view and
indicate
> visually that the region is the target of the link. The manner in which
the
> viewer creates the new display is viewer dependent.
> * If the object contains neither a view context nor a region attribute,
the
> viewer shall move the object into view and indicate visually that the
> graphical primitives of the grobject are the target of the link. The
manner
> in which the viewer creates the new display is viewer dependent. The
> resulting view is a full-picture view, not a zoomed view.
> ### end excerpt ###
>
> The third bullet pertains, as there is neither a 'viewcontext' nor a
> 'region' APS attribute on the target object.
>
> -Lofton.
>
>