gimp_scale_batch.py

#!/usr/bin/python

# optimized for processing screen grabs
# copy and paste into GIMP Python Console
# open all images in Gimp to process
# script scales, sharpens, and exports all open images as PNGs
# Filters > Python-Fu > Console

import importlib

gimpfu_path = '/Applications/Gimp-2.10/Contents/Resources/lib/gimp/2.0/python/gimpfu.py'
gimpfu = importlib.load_source('module.name', gimpfu_path)


def scale_image(image, scale):
    width = image.width
    height = image.height
    scale = 1.0 / scale  # 1.0/.50 = 2 or 50%
    drawable = pdb.gimp_image_active_drawable(image)
    pdb.gimp_context_set_interpolation(INTERPOLATION_CUBIC)
    pdb.gimp_image_scale(image, width / scale, height / scale)
    pdb.plug_in_unsharp_mask(image, drawable, 1.0, 0.25, 0)
    pdb.gimp_context_set_background("#ffffff")
    pdb.gimp_image_flatten(image)


def export_png_file(image, compression):
    drawable = pdb.gimp_image_active_drawable(image)
    # image, drawable, image, image, interlace, compression, bkgd, gama, offs, phys, time, comment, svtrans
    pdb.file_png_save2(image, drawable, image.uri.strip('file:\\\\'), image.name, 0, compression, 0, 0, 0, 0, 0, 0, 0)


def process_images(scale, compression):
    images = gimp.image_list()
    for image in images: # for all open files
        print image.uri
        scale_image(image, scale)  # scale
        export_png_file(image, compression) # compression


# 33% scaling with level 8 compression
process_images(.33, 8)