#77 identify fails to report EXIF data from TIFF files

[Chris Adams]

$ gm identify -format '%f %[EXIF:Orientation] %[EXIF:*]' 016.tif
016.tif
$ exiftool -exif:Orientation 016.tif
Orientation : Rotate 270 CW

In my limited testing, this fails for every non-JPEG image. The perl-based exiftool handles everything I'ved tried. ImageMagick is much slower fails similarly

Tested on OS X (homebrew package):
GraphicsMagick 1.3.17 2012-10-13 Q8 http://www.GraphicsMagick.org/

Also fails on Linux (Ubuntu 10.04):
GraphicsMagick 1.3.12 2010-03-08 Q8 http://www.GraphicsMagick.org/

[Bob Friesenhahn]

EXIF support is currently totally missing for TIFF format. Only JPEG format supports EXIF.

[Chris Adams]

For background: I need something along the lines of the ImageMagick -auto-orient option to ensure that all of the images I send downstream are normalized. Is there a way to read the TIFF orientation flag as well as the EXIF tags?

[Bob Friesenhahn]

FYI, GraphicsMagick reads the TIFF orientation flag and this information (stored in the Image structure) is used by the -auto-orient command option.

We could individually read many EXIF tags from the TIFF and save them as attributes. Capturing the whole EXIF profile is more difficult since EXIF in TIFF uses offsets starting from the beginning of the TIFF file and the data referred to could be anywhere in the TIFF file. To make TIFF EXIF look like EXIF as occurs in JPEG, it would be necessary to write a new EXIF profile which only makes reference to data offsets within the profile.

[Bob Friesenhahn]

Ticket moved from /p/graphicsmagick/bugs/219/

Can't be converted:

• _milestone: