[CREATE] ORA fullscreen viewers

[Alastair M. Robinson]

Hi :)

On 12/09/10 21:05, Martin Renold wrote:

> Applications use their own implementations/libraries for that anyway.

If they have such capabilities, then yes - my concern was simply that 
applications shouldn't be forced to implement such just for the purpose 
of opening ORA files!

> I think ORA is supposed to support patchy implementations. Instead of
> forcing applications to implement each other's features.

Which is fine provided there's some fallback mechanism to get a flat 
graphic that correctly reflects the contents of the file.

> This can be ensured by defining a small set of features (possibly zero) that
> is acceptable for an image viewer to implement.

And as an application developer I would want as many of those features 
to be implemented in a high-level library as possible.  That way any 
application using that library gets the baseline features "for free".

> If additional features are
> used, enough fallbacks must be provided (eg. just a full rendering).

So if a branch of the layer tree requires features beyond the baseline 
to render, an "imposter" layer should be included in the file, which the 
rendering code can use instead of that branch?

> Simple images (layers with well-known blending modes) would stay editable.
> Text/vector layers may be displayed as pixmaps, no longer editable; parts of
> the layer tree may be collapsed because an effect is not implemented.

And this is achieved by substituting a pre-rendered "imposter" layer 
within the file that was created at save-time?

> I think no exchange file format could do better than this, without forcing
> all applications to use the same internal model.

Agreed, yes. :)

All the best
--
Alastair M. Robinson