Re: Patch! Change Time(zone) function

[Mattias Holmlund <mattias holmlund gmail com>]

On 8/16/05, Bengt Thuree <bengt thuree com> wrote:
> Hej
> 
> F-Spot stores all timestamps as UTC.

Yeah, I looked briefly at the code and found a comment about that. But
I can't quite figured out how it is supposed to work. I looked at one
image that I have taken. The exif-information says that the image was
taken at 20:49 on 2005-05-21. The modification time of the file is
also 20:49. The f-spot gui says that the image was taken 18:49. The
sqlite database has time as 1116697783. If I use Perl's localtime (I'm
a perl-guy...) it says that it equals 19:49, but I'm not sure about
how localtime handles timezones.

The correct interpretation would be 22:49 in the +0200 timezone, since
the picture was taken in Stockholm during daylight savings time and my
camera is set to UTC.

What does the time displayed by f-spot mean? Should it be the local
time where the picture was taken, the local time of f-spot at the time
the image was taken or something else?

One solution is to store a display-timezone along with the time. We
could then show the time of my picture as 2005-05-21 22:49 +0200 and a
picture taken in the New York at the same time would show 2005-05-21
16:49 -0400. Both pictures would have the same utc-time stored in the
database, but different values for the display-timezone field.

/Mattias

> 
> -Bengt
> 
> 
> On Ti, 2005-08-16, 04:21 am, Mattias Holmlund skrev:
> > On 8/15/05, Bengt Thuree <bengt thuree com> wrote:
> >> Hej
> > Hej,
> >
> >>
> >> Here is the first release of the ChangePhotoTime routine.
> >>
> >> For a teaser, please check the GUI at
> >> www.thuree.com:8080/bt/testing/F-Spot_TimeZone.jpg
> >>
> >> Please test it and do come with suggestions for features/enhancements.
> >
> > I have given up on remembering to change the time on my camera every
> > time I travel to a different timezone. I always end up forgetting to
> > change it back... Instead, I have set the camera to use UTC time. This
> > means that the timestamp on each image is always a correct UTC time. I
> > haven't quite figured out how I would like f-spot to handle this. Some
> > kind of TimeZone-field where I can keep track of in what timezone the
> > picture was taken perhaps.
> >
> > It might be a good idea to adopt UTC times for all images in F-Spot.
> > You don't necessarily have to set the time to UTC in your camera if
> > you don't want to, but it might make sense for f-spot to always store
> > timestamps in UTC. If f-spot stores the local time where the picture
> > was taken, the picture you took before you boarded the plane might
> > have an earlier timestamp than the picture you took when the plane
> > landed.
> >
> > /Mattias
> >
> >>
> >> Gnome HIG I am not sure I am following, neither proper translation
> >> standards.
> >> This is my second try at coding in Gnome and C# so bear with me please
> >> :)
> >>
> >> The command I used to create the diff files were as follows
> >>   diff -Naur ../f-spot-0.0.13.orig/src/Makefile src/Makefile >
> >> Makefile.diff
> >>   diff -Naur ../f-spot-0.0.13.orig/src/MainWindow.cs src/MainWindow.cs >
> >> MainWindow.cs.diff
> >>   diff -Naur ../f-spot-0.0.13.orig/src/PhotoStore.cs src/PhotoStore.cs >
> >> PhotoStore.cs.diff
> >>   diff -Naur ../f-spot-0.0.13.orig/src/f-spot.glade src/f-spot.glade >
> >> f-spot.glade.diff
> >>
> >>   and then I just copied the ChangePhotoTime.cs file
> >>
> >> The changes I introduced to PhotoStore consist of one new method
> >> (CommitTime (DbItem item))
> >> which updates only the time (thought it was uneccasary to call commit
> >> and
> >> modify tags and all).
> >>
> >> Good luck
> >>
> >> /Bengt
> >>
> >> p.s.
> >> I have based my modifications on F-Spot version 0.0.13
> >>
> >>
> >> -----
> >>
> >> A debug trace from one of my runs...
> >>
> >> nrjbeth brdhcp052-89:~/development/f-spot/f-spot-0.0.13.TimeZone$ f-spot
> >> Photo 20030426_Jasmine_ 006.jpg, Old time 23/04/2003 7:11:06 AM, New
> >> time
> >> 24/04/2003 7:10:06 AM
> >> Photo 20030819_Jasmine_ 009.jpg, Old time 16/08/2003 10:50:27 AM, New
> >> time
> >> 17/08/2003 10:49:27 AM
> >> Photo 20030822_Jasmine 002a.jpg, Old time 21/08/2003 4:36:45 AM, New
> >> time
> >> 22/08/2003 4:35:45 AM
> >> Photo 20040131_JadeJasmine_China_1.JPG, Old time 30/01/2004 2:29:05 AM,
> >> New time 31/01/2004 2:28:05 AM
> >> Photo 20040629 183759_Linköping_PrincessJasmine_004.JPG, Old time
> >> 28/06/2004 8:38:59 AM, New time 29/06/2004 8:37:59 AM
> >> Photo 20040717 125752_Loftahammar_AakesSummerHouse.JPG, Old time
> >> 16/07/2004 2:58:52 AM, New time 17/07/2004 2:57:52 AM
> >> Photo 20040723 142528_Stockholm_Skansen_Jasmine_Bengt_005.JPG, Old time
> >> 22/07/2004 4:26:28 AM, New time 23/07/2004 4:25:28 AM
> >> Photo 20040905181719_Yokohama_SushiTime_Jasmine_000.JPG, Old time
> >> 4/09/2004 8:18:19 AM, New time 5/09/2004 8:17:19 AM
> >> Photo 20041005130110_Mohnani_Jasmine_Bengt.JPG, Old time 4/10/2004
> >> 3:02:10
> >> AM, New time 5/10/2004 3:01:10 AM
> >>
> >>
> >>
> >>
> >> --
> >> Bengt Thuree   bengt thuree com    www.thuree.com/bt
> >>
> >> _______________________________________________
> >> F-spot-list mailing list
> >> F-spot-list gnome org
> >> http://mail.gnome.org/mailman/listinfo/f-spot-list
> >>
> >>
> >>
> >>
> > _______________________________________________
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> >
> >
> 
> 
> --
> Bengt Thuree   bengt thuree com    www.thuree.com/bt
> 
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