gegl command-line

In addition to installing a library, GEGL also installs gegl - a binary/program that permits doing image processing from the command-line as well as an aid during development of GEGL operations. GEGL behaviour can be modified at runtime by setting appropriate environment variables.

Some examples

Render a composition to a PNG file, the composition can be in GEGLs XML format or the one-liner friendly terser gegl-chain format.

$ gegl composition.xml -o composition.png

gegl usage

The following is the usage information of the gegl binary, this documentation might not be complete.

usage: /home/pippin/src/gegl/b/bin/gegl [options] <file | -- [op [op] ..]>

     -h, --help      this help information

     --list-all      list all known operations

     --exists        return 0 if the operation(s) exist

     --info          output information about the operation:
                     name, description, properties details.

     -i, --file      read xml from named file

     -x, --xml       use xml provided in next argument

     -o, --output    output generated image to named file, type based
                     on extension.

     -p              increment frame counters of various elements when
                     processing is done.

     -s scale, --scale scale  scale output dimensions by this factor.

     -X              output the XML that was read in

     -v, --verbose   print diagnostics while running

All parameters following -- are considered ops to be chained together
into a small composition instead of using an xml file, this allows for
easy testing of filters. After chaining a new op in properties can be set
with property=value pairs as subsequent arguments.