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Re: Gzipped svg files in the local filesystem

From: Maciej Stachowiak <mjs@apple.com>
Date: Mon, 08 Nov 2010 13:19:56 -0800
Cc: "public-svg-wg@w3.org" <public-svg-wg@w3.org>
Message-id: <92FDB1F2-9F65-4436-944E-6896F2AEB472@apple.com>
To: Erik Dahlstrom <ed@opera.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
> 
Received on Tuesday, 9 November 2010 01:58:13 GMT

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