gegl

GEGL provides a commandline tool called gegl, for working with the XML data model from file, stdin or the commandline. It can display the result of processing the layer tree or save it to file.

Some examples:

Render a composition to a PNG file:

$ gegl composition.xml -o composition.png

Using gegl with png’s passing through stdin/stdout piping.

$ cat input.png | gegl -o - -x "<gegl>
   <tree>
     <node class='invert'/>
     <node class='scale' x='0.5' y='0.5'/>
     <node class='png-load' path='-'/></tree></gegl>" > output.png

The latest development version is available in the gegl repository in GNOME git.

gegl usage

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

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

  Options:
     -h, --help      this help information

     --list-all      list all known operations

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

     --properties    output the properties (name, type, description) of the operation

     -i, --file      read xml from named file

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

     --dot           output a graphviz graph description

     -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.