[magick-users] Cropping a list of images

[Damien Dunlop]

> > If you want to crop a list of images A, B, C,...
> > and save each of the cropped images as their cropped
> > version, how is this achieved within the one convert command?


> If it is even possible, it's probably not worth it.  Far easier to embed a
> single-file convert command in a loop, either in a shell script (Unix or
> win32/Cygwin), batch file (Windows), or external program of some kind.
> 
> Just for the heck of it, here's a Windows batch file:
> 
> for /f %%i in (filelist.txt) do (
>   convert "%%i" -crop 200x200+10+10 "tmp-%%i" && del "%%i" && ren "tmp-
%%i"
> "%i"
> )
> 

Thanks Ross. However
 
a) Invoking convert multiple times can be slow (have previously
   used a `for' loop  to discover that).
b) The multiple crop command is already embedded in a large 
   shell batch file of various IM commands.
c) I can see a way convert should work

> Have a look at the mogrify command.
> http://imagemagick.org/script/mogrify.php 

Thanks Pete. Trying to stick to `convert' for reasons
previously given and I can see a way it should work.

> Well, as far as I can tell, you cannot do it _within_ convert.

Thanks Vasile, but I can see a way convert might work
using -write and +delete, but I encountered errors.

> You can also do it with convert but have to identify each image 
> separately and use -write. You have to put each of the images except 
> the last into parenthesis.

> convert \( imageA.jpg -crop 100x100+50+50 +repage -write 
> imageAcrop.jpg +delete \) \
> \( imageB.jpg -crop 150x150+200+200 +repage -write imageBcrop.jpg +delete
\) \
> imageC.jpg -crop 75x75+300+300 +repage imageCcrop.jpg

Thanks Fred

Actually, I tried variations of that and kept encountering
error messages. So with increased confidence due to your example,
I went back to the batch file to look for differences but found 
nothing significant. However, I might have had a space after one 
of the `\' because after adjusting the layout a little, it worked!!

What I was trying to use, which did eventually work was a
slight variation on the above:

convert \( A.gif -crop 100x100+50+50 +repage -write AA.gif  \) \
           +delete \
        \( B.gif -crop 150x150+200+200 +repage -write BB.gif \) \
           +delete \
        ...
           Z.gif -crop 75x75+300+300 +repage ZZ.gif

PS: I have to use gif files not only for historical reasons.
Of more importance, is the fact that a large number of features
in the images must each retain their specific `standard' colour.

Regards