[Shotwell] New and recent changes in Shotwell trunk

[Jim Nelson]

For everyone compiling Shotwell straight from trunk, there are
important changes being made that you should be aware of.  *This is
especially important for downstream providers.*  End users may find
what follows interesting as well.

* First, if you're actively following Shotwell's development in trunk,
you've already discovered we now have limited/minimal/basic RAW
support.  There are outstanding issues with even this level of
support, but it's there and it essentially works.  (On the other hand,
there are plenty of RAW features we'd like to have but are not
present; see Shotwell's ticket bank for more information:
http://trac.yorba.org/report/16)

RAW support comes via libraw, the libraricized version of dcraw.
Unfortunately there are no PPAs or repositories holding libraw (none
that I know of, at least), so it must be downloaded and installed from
tarball.  We are planning to have a version available on our PPA in
time for 0.6.

We would prefer if someone else would step up and take ownership of
the packaging task.  We would *really* prefer it if the distros made
it available in their standard repositories.

If you're interested in championing libraw packaging, please contact
the Shotwell team at shotwell at yorba.org.  Or, drop a note on this
mailing list.

Shotwell currently relies on libraw 0.9.0.  Download it from
http://www.libraw.org/download

* Second, Shotwell is migrating away from libexif to Exiv2, which is
actively maintained and more mature.  Exiv2 also brings to Shotwell
XMP and IPTC support on a wide variety of photo file formats
(including JPEG, PNG, TIFF, and RAW).  The good news is, Exiv2 is
packaged and widely available in repositories.  The bad news is, Exiv2
is written in C++, meaning we need a wrapper of some kind in order to
use it in Vala.

Fortunately we discovered a nascent GObject-based wrapper called
gexiv2 written by Mike Gemuende.  Mike graciously blessed a fork of
his project, and Yorba is now its maintainer.  More information may be
found here: http://trac.yorba.org/wiki/gexiv2

I've committed to Shotwell trunk a patch that moves the code away from
libexif and to gexiv2.  libexif is still required due to a single
limitation of Exiv2 -- its developers are aware of it and it may be
fixed in the future.  (See
http://dev.exiv2.org/boards/3/topics/show/499 and
http://dev.exiv2.org/issues/show/467)  Until then, Shotwell will
depend on both libexif and gexiv2.

As you can see, Shotwell 0.6 is shaping up to be a a major release.  Stay tuned!

-- Jim