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Re: Gzipped svg files in the local filesystem

From: Erik Dahlstrom <ed@opera.com>
Date: Tue, 09 Nov 2010 15:02:32 +0100
To: public-svg-wg@w3.org
Message-ID: <op.vlwpafblgeuyw5@localhost>
Sounds like a good topic for the Thursday telcon.

On Mon, 08 Nov 2010 22:19:56 +0100, Maciej Stachowiak <mjs@apple.com>  

> - It would be useful to also assign gzip'd SVG files their own MIME  
> type. This is useful both for systems that map file type to a MIME type,  
> and the occasional compressed gzip still sent without content-encoding,  
> so they can stop violating the +xml MIME type convention.
> - Not all operating systems map file types by extension, so it seems  
> unwise to fix that approach in the spec.
> - As wrotten, there's nothing obvious that limits this .svgz extension  
> rule to files in the local filesystem. Applying it to any file served  
> over HTTP extension, rather than looking at the MIME type, would of  
> course be completely wrong.
> Regards,
> Maciej
> On Nov 7, 2010, at 7:58 AM, Erik Dahlstrom wrote:
>> Hello svg-wg,
>> I've been looking at the 1.1 and 1.2T specifications for conformance  
>> criteria for svg viewer UA:s in particular when encountering an *.svgz  
>> file in the local filesystem. I can't find a requirement for such files  
>> to be displayed - surely the intention isn't that such files must cause  
>> an error message to appear in the UA?
>> Reading [1] it seems clear that *.svgz files don't fulfill the  
>> requirements for being a "conforming standalone svg stand-alone file".  
>> Should there be a similar conformance class for svgz files (along with  
>> clear requirements for displaying such files), or is wasting diskspace  
>> considered to be a good thing? Incidentally it would also mean that e.g  
>> Inkscape and Illustrator are not "Conforming SVG Generators".
>> Here's my proposed new wording (to be added to the confomance criteria  
>> appendix):
>> [[ Conforming Compressed SVG Stand-Alone Files
>> A file is a Conforming Compressed SVG Stand-Alone File if:
>> - the first bytes of the file are 0x1F8b (the fixed ID1 and ID2 fields  
>> from the gzip file format header, as defined in RFC1952),
>> - the file extension is "svgz",
>> - the decompressed contents of the file fulfills all the requirements  
>> for "Conforming SVG Stand-Alone Files".
>> ]]
>> and changing G.6 to be:
>> [[ Conforming SVG Generators
>> A Conforming SVG Generator is a program which:
>> - always creates at least one of Conforming SVG Document Fragments,  
>> Conforming Compressed SVG Stand-Alone Files or Conforming SVG  
>> Stand-Alone Files.
>> - does not create non-conforming SVG document fragments of any of the  
>> above types.
>> ]]
>> Finally add a clause that requires either "Conforming SVG Interpreters"  
>> or "Conforming SVG Viewers" to support "Conforming Compressed SVG  
>> Stand-Alone Files".
>> Cheers
>> /Erik
>> [1] http://www.w3.org/TR/SVG11/conform.html#ConformingSVGStandAloneFiles
>> --
>> Erik Dahlstrom, Core Technology Developer, Opera Software
>> Co-Chair, W3C SVG Working Group
>> Personal blog: http://my.opera.com/macdev_ed

Erik Dahlstrom, Core Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group
Personal blog: http://my.opera.com/macdev_ed
Received on Tuesday, 9 November 2010 14:03:07 UTC

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