Re: image-dired does not rotate the original image

[Dieter Wilhelm <dieter@duenenhof-wilhelm.de>]

"Mathias Dahl" <mathias.dahl@gmail.com> writes:

>> emacs -Q
>> M-x tumme [some directory with jpegs]
>> R (image-dired-rotate-original-right)
>>
>> yields the following error message:
>>
>>   image-dired-rotate-original: Could not rotate image
>
> By default, `image-dired-cmd-rotate-original-program' is set to
> jpegtran, which is a command that can rotate a JPEG without quality

I'm sorry, I was convinced that the image-magick suite would be enough
for tumme's image manipulations but now I see that you mentioned
jpegtran in the manual.

Lets see what the respective debian package name is:
$ apt-file search jpegtran
libjpeg-progs: usr/bin/jpegtran

> loss. This is a must, unless there are other tools that does the same

Why can't you just use convert?  It's needed for the image-dired
thumbs anyway, is it too slow?

> job. Do you have this program installed? Can you call it from a
> terminal?

OK, installed libjpeg-progs and it works now, thanks.  But its a bit
awkward since I'm constantly asked whether I'd like to change the
original file and when I decline the rotated display is again
reverted.  I could imagine that this becomes very annoying when
displaying stuff from a read only drive.

Does it make sense to check the existence of the needed image-magick
and jpegtran executables with the Emacs configure script?

And it would be helpful if the error message could give a hint which
kind of executable is missing.

-- 
    Best wishes

    H. Dieter Wilhelm
    Darmstadt, Germany