[x3d-public] considering general conversion of metadata - containerField default in XML encoding (corrected copy)

[Don Brutzman]

[Corrected copy, please discard prior version.  Also inserted asterisks to highlight comparisons of interest in examples b. and c.]

On 4/6/2017 9:09 AM, Don Brutzman wrote:
> [...]
> b. containerField="value" is awfully verbose.  Might we flip this around by changing the default containerField value?  This would change some existing content, but not by much, and this is a tricky business in any case so checking is always needed.  Might make sense to set up for the most common long-term case.

Illustrating examples follow.  Equivalent versions a. and b. with current XML schema, possible alternative c.

==============================
a. original

<WorldInfo DEF='ModelMetadata' title='CaffeinePubChem2519SticksColor.x3d'>
   <MetadataSet name='xmlns:chimera' reference='http://www.cgl.ucsf.edu/chimera'>
     <MetadataString containerField='value' name='comment' value='"X3D profile limits on number of elements/colors/etc. were ignored"'/>
     <MetadataSet containerField='value' name='chimera:WindowSize'>
       <MetadataInteger containerField='value' name='height' value='512'/>
       <MetadataInteger containerField='value' name='width' value='512'/>
     </MetadataSet>
     <MetadataSet containerField='value' name='chimera:DepthCue'>
       <MetadataFloat containerField='value' name='color' value='1 1 1'/>
       <MetadataFloat containerField='value' name='range' value='35.2169 40.437'/>
     </MetadataSet>
   </MetadataSet>
</WorldInfo>

==============================
b. equivalent, fully elaborated, note change in MetadataSet

<WorldInfo DEF='ModelMetadata' title='CaffeinePubChem2519SticksColor.x3d'>
   <MetadataSet *containerField='metadata'* name='xmlns:chimera' reference='http://www.cgl.ucsf.edu/chimera'>
     <MetadataString *containerField='value'* name='comment' value='"X3D profile limits on number of elements/colors/etc. were ignored"'/>
     <MetadataSet *containerField='value'* name='chimera:WindowSize'>
       <MetadataInteger *containerField='value*' name='height' value='512'/>
       <MetadataInteger *containerField='value'* name='width' value='512'/>
     </MetadataSet>
     <MetadataSet *containerField='value'* name='chimera:DepthCue'>
       <MetadataFloat *containerField='value'* name='color' value='1 1 1'/>
       <MetadataFloat *containerField='value'* name='range' value='35.2169 40.437'/>
     </MetadataSet>
   </MetadataSet>
</WorldInfo>

==============================
c. alternative: flip the defaults in XML Schema/DTD.  Note clarity of contained content.

<WorldInfo DEF='ModelMetadata' title='CaffeinePubChem2519SticksColor.x3d'>437' /> -->
   <MetadataSet *containerField='metadata'* name='xmlns:chimera' reference='http://www.cgl.ucsf.edu/chimera'>
     <MetadataString name='comment' value='"X3D profile limits on number of elements/colors/etc. were ignored"'/>
     <MetadataSet name='chimera:WindowSize'>
       <MetadataInteger name='height' value='512'/>
       <MetadataInteger name='width' value='512'/>
     </MetadataSet>
     <MetadataSet name='chimera:DepthCue'>
       <MetadataFloat name='color' value='1 1 1'/>
       <MetadataFloat name='range' value='35.2169 40.437'/>
     </MetadataSet>
   </MetadataSet>
</WorldInfo>

==============================

d. Impacts.

- no changes to abstract specification or non-XML encodings.

- change default value in XML Schema, XML DTD, Object Model for X3D (OM4X3D)

- change to Canonical X3D .xml default and X3D Binary .x3db default.

- Need diagnostics to check XML scenes, but this would be straightforward (X3D Tooltips, X3D Validator, X3D Tidy, etc.)

==============================

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman