#
# Simple python module to add a black fadeout effect to a given image
#

#
# apt-get install -y gimp gimp-python
#
# gimp -i -d -f --batch-interpreter python-fu-eval -b 'import sys; sys.path=["."]+sys.path;import gimp_fadeout; gimp_fadeout.apply()'
#

import sys, os

from gimpfu import *

def apply():
    try:
        # ---
        # Configuration
        # ---
        fadeout_from = 0.98
        fadeout_until = 0.1
        image_path = os.environ['FADEOUT_IMAGE']

        if not os.path.exists(image_path):
            raise NameError('image does not exists')

        if 'FADEOUT_FROM' in os.environ and os.environ['FADEOUT_FROM']:
           fadeout_from = float(os.environ['FADEOUT_FROM'])

        if 'FADEOUT_UNTIL' in os.environ and os.environ['FADEOUT_UNTIL']:
           fadeout_until = float(os.environ['FADEOUT_UNTIL'])

        image_filename = os.path.basename(image_path)
        black_image_path = 'black_image_' + image_filename
        fadeout_path = 'fadeout_' + image_filename

        # ---
        # Gimp context configuration
        # ---
        print('Configuring Gimp context...')
        pdb.gimp_context_set_default_colors()
        pdb.gimp_context_set_gradient_fg_bg_rgb()

        # ---
        # Create base black image
        # ---
        print('Creating base black image...')
        image = pdb.gimp_file_load(image_path, RUN_NONINTERACTIVE)
        width = image.width
        height = image.height

        layer = gimp.Layer(image, 'Black Layer', width, height, RGB_IMAGE, 100, NORMAL_MODE)
        image.add_layer(layer)

        pdb.gimp_image_merge_visible_layers(image, CLIP_TO_IMAGE)
        pdb.file_jpeg_save(image, image.active_layer, black_image_path, black_image_path, 1,0,1,0,0,0,0,0,0)
        pdb.gimp_image_delete(image)

        # ---
        # Create Fadeout
        # ---
        print('Adding fadeout to original image...')

        # Open black image
        black_image = pdb.gimp_file_load(black_image_path, RUN_NONINTERACTIVE)

        # Load main image as layer
        image = pdb.gimp_file_load_layer(black_image, image_path)
        black_image.add_layer(image)

        # Create layer mask
        mask = pdb.gimp_layer_create_mask(image, ADD_MASK_WHITE)

        # Add layer mas to main image
        pdb.gimp_layer_add_mask(image, mask)

        # Apply gradient
        x1 = width / 2
        y1 = height * fadeout_from
        y2 = y1 - (y1 * fadeout_until)

        pdb.gimp_drawable_edit_gradient_fill(mask, GRADIENT_LINEAR, 0, 0, 0, 0, 0, x1, y1, x1, y2)

        # Merge layers into black image
        pdb.gimp_image_merge_visible_layers(black_image, CLIP_TO_IMAGE)

        # ---
        # Save Image with Fadeout
        # ---
        print('Saving image with fadeout...')
        pdb.file_jpeg_save(black_image, black_image.active_layer, fadeout_path, fadeout_path, 1,0,1,0,0,0,0,0,0)

        # ---
        # Clean Up
        # ---
        print('Done!!!')

        # Delete temporarily files
        os.remove(black_image_path)

        # Delete images from gimp context
        pdb.gimp_image_delete(black_image)
    except Exception as e:
        print("ERROR: " + str(e))

    finally:
        pdb.gimp_quit(1)