[Digikam-users] exif orientation

[Milan Knížek]

jdd-gmane píše v Ne 03. 01. 2010 v 21:52 +0100:

> Do you happen to know the imagemagic syntax to do this? if not, don't
> worry, I will find it tomorrow

If your images are JPEGs, then you want to use jhead and jpegtran
instead of ImageMagick, to use a lossless rotation.

$ man jhead

ROTATION OPTIONS
       -autorot
              Using  the  'Orientation' tag of the Exif header,
              rotate the image so that it is upright.  The pro‐
              gram  jpegtran  is  used to perform the rotation.
              This program is present in most  Linux  distribu‐
              tions.   For  windows,  you need to get a copy of
              it.  After rotation, the orientation tag  of  the
              Exif  header  is set to '1' (normal orientation).
              The thumbnail is also rotated.  Other  fields  of
              the   Exif   header,   including  dimensions  are
              untouched,  but   the   JPEG   height/width   are
              adjusted.  This feature is especially useful with
              newer Canon cameras, that set the orientation tag
              automatically using a gravity sensor.

Regards,

Milan Knizek
knizek (dot) confy (at) volny (dot) cz
http://www.milan-knizek.net - About linux and photography (Czech
language only)