[CREATE] OpenRaster and filters

[Øyvind Kolås]

On Mon, Jun 16, 2008 at 8:41 AM, Kai-Uwe Behrmann <ku.b at gmx.de> wrote:
> Validation of variables is very useful to find out a matching filter.
> As the image description (OpenRaster) and the filter are different things,
> I'd say this makes sense. I am assuming here concurrenting filter sets,
> which can easily occure. The core of OpenRaster could specify a set of
> core filters. If this is easier to validate in attributes syntax, why not?
> If for extensions, compared to the OpenRaster core, the elements approach
> seems more easy, so take this?

We'd probably have a core set of filters that are part of the
standard, GEGL would have it's own set of filters in it's own name
space, so would GIMP (by adding additional plug-ins). In the same
manner krita would be extending it with it's own filters. The user
himself might download plug-ins for any of the above mentioned
packages that install yet more filters and composers that can be used
when describing OpenRaster documents; this is where I think automatic
validation based on XML schemas loaded from plug-ins etc fail; since
an OpenRaster file might very well be using plug-ins that are not
available in the host loading the document. Making this load fail
gracefully (or fall back to stored caches in the composition) is what
I see as problematic.

> After all it might appear like a feature, to check for strict or
> lazy following the OpenRaster specification.

There already has been discussions about various levels of confrmance
or strictness. This is more about which core functionality is used,
the representation of the buffers (additional files stored along the
.xml) etc. It is for instance very likely that GEGL will not use
OpenRaster files with .png's .jpg's or .exr's when saving natively but
use some of the same technologies using it's internal GeglBuffer
on-disk representation.

/Øyvind K.
-- 
«The future is already here. It's just not very evenly distributed»
 -- William Gibson
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