[Insight-developers] MetaIO - versioning

[Bill Lorensen]

Sounds like a good idea to me. It will help backward compatibility of
meta files in the future.


On Sun, Jan 23, 2011 at 11:59 AM, Stephen Aylward
<stephen.aylward at kitware.com> wrote:
> Hi ITK'ers.
>
> Proposal
> =======
> I am writing to propose adding version information to metaObject
> files, including meta images.
>
> Problem addressed
> ===============
> Meta was created 14+ years ago and needs updating.   This will allow
> us to better support images of vectors of vectors, spacing per slice,
> ...
>
> Method
> ======
> We could add a Met_ReadVersion function for meta object developers
> that returns a version number for a file's format.   The version
> number can be read from a file without reading the other contents of a
> file.   MetaObject readers would be able to adjust the fields they
> read from a file based on that version.  MetaObject writers should be
> able to write to older version formats as well as the current version
> format.
>
> The version tag will be set to 1.0 for all object formats at this
> time.   Thus, if a version number hasn't been specified in the file,
> the MET_ReadVersion function returns 1 (corresponding to the current
> version of meta).   Moving forward, each object can increase its
> version - that is, there will not be a global version number, it will
> be object specific.
>
> Justification for design: Currently, there is a function
> "Met_ReadForm" that allows a developer to query the type of object in
> a meta file (e.g., image, matrix, arrow, tube,...).    The proposed
> MET_ReadVersion function follows that pattern.
>
> The file tag will be "ObjectVersion".
> The value of ObjectVersion with be an unsigned int.  (no concept of
> minor/major versioning will be provided).
> -- The tag is ObjectVersion and not FileVersion because the content of
> the file/object will change, not just its organization in the file.
>
> Comments / suggestions / concerns?
>
> s
>
> --
>
> ==============================
> Stephen R. Aylward, Ph.D.
> Director of Medical Imaging Research
> Kitware, Inc. - North Carolina Office
> http://www.kitware.com
> stephen.aylward (Skype)
> (919) 969-6990 x300
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://kitware.com/products/protraining.html
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-developers
>