01-15-2018, 10:02 PM
Most Python scripts just declare parameters and Gimp builds a parameter dialog on the fly when they are called. Those that don't either don't take parameters other than image+layer, or have a whole GUI written in Python. For a standard Python script that uses this autogenerated dialog, see Filters>Render>Cloud>Fog... (in your installation as (lib/gimp/2.0/plug-ins/foggify.py).