[Digikam-devel] About dcraw, libufraw, libopenraw and libkdcraw

[Gilles Caulier]

2007/4/2, Leopold Palomo Avellaneda <lepalom at wol.es>:
>
> Dear people,
>
> first of all I'm sorry for write you with also cc to some list. I will try
> to
> be brief. I'm an advocate of the free software and usually I use kde and
> debian. I'm a enthusiast of the photography and I normally shot in raw
> with
> my camera.
>
> It's to me a bit surprising (but understandable) that almost _all_ the
> free
> software projects use the dcraw from Mr. Coffin. However, Mr. Coffin
> doesn't
> want to make dcraw as a library. In general, all the projects modify the
> dcraw code or encapsulate it in some kind of library.


We need a library, not a simple binary program to decode RAW files. This is
why there are a lots of projects witch re-implemente/re-use dcraw.c from
Dave

I like the ideas from Mr. Figuière to develop a library to use in the free
> software projects for the raw. But, to begin a new library from scratch,
> (or
> I understand that it have been developed in this manner) is a lot of work.


Exact. This is why i think this project will never out, or perhaps in a far
far future...


However, maybe it's the most easy thing, do it your self from zero.


no. RAW file decoding is a science of reverse engineering. Dave have used 10
years of like to provide dcraw.c


Since some time ago I use ufraw to convert my photos to something viewable.
> I
> like very much Mr. Fuchs application and I think that he have designed and
> developed a very good application to convert raw files. Also, I think that
> the idea to have some kind of job ticket, or convert options that he
> propose
> in the ufraw xml file it's a very good idea.
>
> I proposed to Mr. Fuchs to try to make the ufraw file description (xml)
> as "standardized" file format in the way that you could use it in any
> application having the same (or very similar) results. Mr. Fuchs told me
> that
> one way to do it is encapsulate ufraw in a library.


fine.

I don't use digikam but I like very much this application. Also, I like the
> qt
> and the kde project. I have been a bit surprised when today looking on the
> blog of digikam I have been an entry about the libkdcraw. However, I have
> seen that has a dependency with the kdelibs, as normal as a kde lib.


libkdcraw provide and interface for KDE applications. This implementation
come from digiKam core and will be used by digiKam 0.9.2 and kipi-plugins
0.1.4. In the future, Krita will use it when libkdcraw will be ported to
QT4/KDE4. I'm sure than KDE KIO slave will use it later...

The implementation provide an C++ interafce witch use QT and KDE component
to run. Also, libkdcraw provide a QT/KDE settings widget used by hosts
application to set RAW decoding parameters.

There is no plan to remove the KDE/Qt. This is a non sence. If a low level
library need to be done, libkdcraw is not the good way.

After this introduction I would like to ask you if it would be possible that
> _all_ of you will try to collaborate as possible as you can. For example,
> I
> respect very much the ideas of Mr. Coffin, but:
>
> - what do you think if the other people send you little modifications of
> the
> dcraw in the manner to help it to integrate in a library?


This is must be done in a low level library... like an ufraw-lib for
example. This will be easy to fix libkdcraw to support ufraw shared lib
instead dcraw.c.


(I have in mind the
> little  modification that the libkdcraw have to do obtain the model and
> camera


Already done in libkdcraw, plus others stuff... (:=)))... Are you already
used digiKam ?


- Mr. Wiesweg and Mr. Caulier (digikam) what do you think to modify
> libkdcraw
> to avoid any dependency of qt or kde in the way that the gnome team
> (remember, I use kde!!!! ;-) ) or whatever program could use it?


no... see below...


- Mr. Fuchs, what do you think to begin to modify ufraw in a way that use
> this possible library or another in common?


This is the better way...

Question : where is Dave Coffin job in this mail ? This is the main actor
about RAW file format reverse-engineering ! If a low level shared lib is
created for that, Dave is the better guy to do the core. Others developpers
can maintain and adapt the lib interface...

Regards

Gilles Caulier
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