A custom GEGL operation (and by extension GIMP filter) that implements a pixel sorting effect. To use it click "Tools->GEGL Operation" and choose "Pixel Sort" in the dropdown.

This is primarily a port of the following processing script to a GEGL operation: https://github.com/kimasendorf/ASDFPixelSort

To compile and install you will need the GEGL header files (libgegl-dev on Debian based distributions or gegl on Arch Linux) and meson (meson on most distributions).

meson setup --buildtype=release build
ninja -C build
cp build/pixelsort.so ~/.local/share/gegl-0.4/plug-ins

If you have an older version of gegl you may need to copy to ~/.local/share/gegl-0.3/plug-ins instead (on Ubuntu 18.04 for example).

NOTE: as of writing this pixelsort seems to not work with gegl-0.3. It works when run with the GEGL command line utility but for some reason none of the operation's properties show up in the GEGL tool window.

The easiest way to compile this project on Windows is by using msys2. Download and install it from here: https://www.msys2.org/

Open a msys2 terminal with C:\msys64\mingw64.exe. Run the following to install required build dependencies:

pacman --noconfirm -S base-devel mingw-w64-x86_64-toolchain mingw-w64-x86_64-meson mingw-w64-x86_64-gegl

Then build the same way you would on Linux:

meson setup --buildtype=release build
ninja -C build

To install it, copy the resulting DLL (build/pixelsort.dll) to the folder where GIMP finds GEGL operations:

cp build/pixelsort.dll '/c/Program Files/GIMP 2/lib/gegl-0.4/

Or if you already have a pre-built pixelsort.dll just copy it to C:\Program Files\GIMP 2\lib\gegl-0.4\ .

Original image:

Vertical sorting with luminance as the mode:

Horizontal sorting with white level as the mode:

Complete vertical sorting by luminance (threshold of 0):