command-line gif creation with GIMP (proof of concept)

gifify.py

from __future__ import print_function

import itertools
import glob

from gimpfu import pdb  # (although already defined when called from gimp)

def gifify(*args):
    """Load a list of sorted glob patterns of images and create a gif called out.gif"""

    file_iter = itertools.chain.from_iterable(sorted(glob.glob(arg)) for arg in args)

    # load first image, add the rest as layers
    first = next(file_iter)
    img = pdb.gimp_file_load(first, first)

    for infile in file_iter:
        lay = pdb.gimp_file_load_layer(img, infile)
        # we also have to explicitly attach the new layer to the image
        pdb.gimp_image_insert_layer(img, lay, None, -1)

    # convert image to indexed (either that or grayscale needed for gif)
    pdb.gimp_image_convert_indexed(
        img,  # image
        0,    # dither (no dither)
        0,    # palette (make one)
        255,  # num_colors
        0,    # alpha_dither (no alpha dither for fake partial opacity)
        0,    # remove_unused (don't remove unused or duplicate colors)
        ""    # palette (unused)
    )

    # save as a looping gif with some parameters
    outfile = "out.gif"
    pdb.file_gif_save(
        img,                  # image
        img.active_drawable,  # drawable (active layer, really)
        outfile,              # filename
        outfile,              # raw_filename
        0,                    # interlace (don't)
        1,                    # loop (do)
        1000,                 # delay (in milliseconds)
        2                     # dispose (disposal strategy: replace)
    )
    print(outfile, "done.")

    pdb.gimp_image_delete(img)

run_example.sh

# hack: need to add . to path :'(
PYTHONPATH='.':$PYTHONPATH gimp-console --batch-interpreter python-fu-eval -b 'import gifify; gifify.gifify("pics/img*.jpg"); pdb.gimp_quit(0)'