Ubuntu – How to blur an image from command line

ImageMagick Trim

The command line option trim used together with convert, or mogrify lets you trim borders of the identical color as the corners of an image.

Usage:

convert input.png -trim output.png

The additional options -fuzz (which takes a percentage as an argument, e.g. -fuzz 10%) also removes colors near the corner colors. Use the option +repage to remove a canvas (if applicable).

ImageMagick Batch Trim (find)

Above command for ImageMagick Trim can also be used to batch processing images while combined with find command:

find ./ -name "pattern" -exec convert {} -trim outputfolder/{} \;

will trim all images that fits pattern part of command and save them in new folder named outputfolder.

Assuming that images are PNGs, then command will look like this:

find ./ -name "*.png" -exec convert {} -trim outputfolder/{} \;

ImageMagick Batch Trim (mogrify)

While find allows for much greater control where output files will be placed, it is also possible to do the same with ImageMagick's mogrify:

mogrify -trim *.png

and if you want to crop colors near the corner colors (adjust the percentage based on the results you are observing):

mogrify -trim -fuzz 10% *.png

Please note that unlike convert and batch operation with find and convert mogrify overwrites all files. To keep the originals use the -path option or do a backup copy of all images in the directory before proceeding with mogrify command.

Side note: mogrify can be used to execute most (if not all) convert operations in batch, while overwriting original files.

As Trevor noted in the comments, you can -path option to output converted files to a new directory without overwriting original files:

mogrify -trim -path trimmed_folder/ *.png

IrfanView

IrfanView runs quite nicely with Wine. Be sure to check the output of Irfanview carefully, as it sometimes breaks images when used with Wine.

I had time to have a go at @Rinzwind's mentioned ooopy - to install it, download the latest version from here, then extract it and run the setup.py as mentioned here - or just run these commands to install the currently latest version 1.11:

wget http://downloads.sourceforge.net/project/ooopy/ooopy/1.11/OOoPy-1.11.tar.gz
tar -xf OOoPy-1.11.tar.gz
cd OOoPy-1.11/
sudo python ./setup.py install

You can then use it like this:

ooo_cat file1.odt file2.odt file3.odt > file123.odt

this may also work:

ooo_cat file1.odt file2.odt file3.odt -o file123.odt

I have only tried it with three ODTs with small amounts of text.