Join Ultra Fractal splitted images

#!/usr/bin/env python

# uf_pic_join.py
#
# Author:
#      Carlos Lamas
# Date:
#      2021-04-14
# Version:
#      1.1
# Copyright:
#      This code is licensed as public domain and can be used
#      without any restriction
# Description:
#      This script allows to join a set of splitted tiles of an
#      Ultra Fractal rendered image in a single image. Ultra
#      Fractal images size are limited to 2GiB so splitted images
#      may be required to render bigger images
# Requirements
#      * libvips instaled and configured in system path
#      * pyvips binding installed
#      * python is required to run the script
# Command syntax:
#      python uf_pic_join.py <corner_pic_file> <destination_file>
# Command example:
#      python uf_pic_join.py 'my fractal E4.png' 'full fractal.png'
# Notes:
#      * <corner_pic_file> is the name of the bottom right corner
#        tile (something like 'myfractal E4.png')
#      * <destination_file> is the name of the file to contain the
#        mosaic with all the picture parts joined. It has not to
#        be the same file format as the source image parts
#      * Tested only in Windows OS and Python 3. Some tweaking can
#        be necessary to run it in another OS
#      * Using older libvips version 8.9.2 due to some issues
#        related to pyvips with current versions 8.10.x
#


import os, os.path
import sys, time
import logging
import pyvips



# Set the following constants to configure the command execution
LOGGING_LEVEL = logging.WARNING
PIVIPS_CACHE_TRACE = False
PIVIPS_REPORT_RAM_LEAKED = True



# Initialize eval handler last_time "static" variable
def preeval_handler(image, progress):
    eval_handler.last_time = 0
    preeval_handler.start_time = time.time()
    print('Joining images...')
    print('Percent complete: {0}%'.format(progress.percent), end = "")


# Eval handler used to track the progress of the operation
# Print the percent of operation done (only once every second)
def eval_handler(image, progress):
    current_time = progress.run   # time counter
    if current_time - eval_handler.last_time >= 1:
        print('\rPercent complete: {0}%'.format(progress.percent), end = "")
        eval_handler.last_time = current_time


# Force printing the percent at the end
def posteval_handler(image, progress):
    print('\rPercent complete: {0}%'.format(progress.percent))
    print('Total time spent: {0:.2f}s'.format(time.time() - preeval_handler.start_time))


# Print the shell command syntax
def print_command_syntax():
    print("Command syntax: python {0} <last_mosaic_file> <destination_file>".format(sys.argv[0]))


def main():

    # Check 2 arguments are passed to the command
    if len(sys.argv) != 3:
        print("Invalid number of arguments ({0}).".format(len(sys.argv) - 1))
        print_command_syntax()
        return -1

    # Source files (2nd command argument)
    src_file_path, src_file_name = os.path.split(os.path.normpath(sys.argv[1].strip()))
    src_file_name, src_file_ext = os.path.splitext(src_file_name)

    # Destination file (3rd command argument)
    dst_file_path, dst_file_name = os.path.split(os.path.normpath(sys.argv[2].strip()))
    dst_file_name, dst_file_ext = os.path.splitext(dst_file_name)


    # Check source file names
    if len(src_file_name) <= 3 or src_file_name[-3] != ' ':
        print("Invalid source file: '{0}'".format(src_file_name))
        print_command_syntax()
        return -1


    # The row is the last character and the column is the second last
    rows = src_file_name[-1]           # digit 0..9
    cols = src_file_name[-2].upper()   # character A..I

    rows = "123456789".find(rows) + 1   # 1..9
    if rows == 0:
        print("Invalid source file name. Invalid row coordinate")
        return -1

    cols= "ABCDEFGHI".find(cols) + 1   # 1..9
    if cols == 0:
        print("Invalid source file name. Invalid column coordinate")
        return -1


    # pyvips configuration
    pyvips.cache_set_trace(PIVIPS_CACHE_TRACE)
    pyvips.base.leak_set(PIVIPS_REPORT_RAM_LEAKED) # show memory used


    # Create image list with sorted source files
    image_list = []
    src_file_name = src_file_name[:-2]  # remove coordinates to get the base name
    for r in range(rows):
        for c in range(cols):
            suffix = chr(ord('A') + c) + str(r + 1)
            file_name = os.path.join(src_file_path, src_file_name + suffix + src_file_ext)
            image = pyvips.Image.new_from_file(file_name, access='sequential')
            image_list.append(image)


    # Abort when destination file already exists
    dst_file = os.path.join(dst_file_path, dst_file_name + dst_file_ext)
    if os.path.exists(dst_file):
        print('Invalid destination file. A file or folder with that name already exists.')
        return -1

    dst_image = pyvips.Image.arrayjoin(image_list, across = cols)


    # Configure tracking handlers
    dst_image.set_progress(True)
    dst_image.signal_connect('preeval', preeval_handler)
    dst_image.signal_connect('eval', eval_handler)
    dst_image.signal_connect('posteval', posteval_handler)

    dst_image.write_to_file(dst_file)

    return 0


# Run main()
if __name__ == "__main__":

    logging.basicConfig(level = LOGGING_LEVEL)
    result = main()
    exit(result)