generate_emoji_thumbnails.py

#!/usr/bin/env python
# Copyright 2017 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Generate 72x72 thumbnails including aliases.

Takes a source directory of images named using our emoji filename
conventions and writes thumbnails of them into the destination
directory.  If a file is a target of one or more aliases, creates
copies named for the aliases."""


import argparse
import collections
import logging
import os
from os import path
import shutil
import subprocess

import add_aliases

from nototools import tool_utils
from nototools import unicode_data

logger = logging.getLogger('emoji_thumbnails')

def create_thumbnail(src_path, dst_path):
  # uses imagemagik
  # we need imagex exactly 72x72 in size, with transparent background
  subprocess.check_call([
      'convert', '-thumbnail', '72x72', '-gravity', 'center', '-background',
      'none', '-extent', '72x72', src_path, dst_path])


def get_inv_aliases():
  """Return a mapping from target to list of sources for all alias
  targets in either the default alias table or the unknown_flag alias
  table."""

  inv_aliases = collections.defaultdict(list)

  standard_aliases = add_aliases.read_default_emoji_aliases()
  for k, v in standard_aliases.iteritems():
    inv_aliases[v].append(k)

  unknown_flag_aliases = add_aliases.read_emoji_aliases(
      'unknown_flag_aliases.txt')
  for k, v in unknown_flag_aliases.iteritems():
    inv_aliases[v].append(k)

  return inv_aliases


def filename_to_sequence(filename, prefix, suffix):
  if not filename.startswith(prefix) and filename.endswith(suffix):
    raise ValueError('bad prefix or suffix: "%s"' % filename)
  seq_str = filename[len(prefix): -len(suffix)]
  seq = unicode_data.string_to_seq(seq_str)
  if not unicode_data.is_cp_seq(seq):
    raise ValueError('sequence includes non-codepoint: "%s"' % filename)
  return seq


def sequence_to_filename(seq, prefix, suffix):
  return ''.join((prefix, unicode_data.seq_to_string(seq), suffix))


def create_thumbnails_and_aliases(src_dir, dst_dir, dst_prefix):
  """Creates thumbnails in dst_dir based on sources in src.dir, using
  dst_prefix. Assumes the source prefix is 'emoji_u' and the common suffix
  is '.png'."""

  if not path.isdir(src_dir):
    raise ValueError('"%s" is not a directory')
  dst_dir = tool_utils.ensure_dir_exists(dst_dir)

  src_prefix = 'emoji_u'
  suffix = '.png'

  inv_aliases = get_inv_aliases()

  for src_file in os.listdir(src_dir):
    try:
      seq = unicode_data.strip_emoji_vs(
          filename_to_sequence(src_file, src_prefix, suffix))
    except ValueError as ve:
      logger.warning('Error (%s), skipping' % ve)
      continue

    src_path = path.join(src_dir, src_file)

    dst_file = sequence_to_filename(seq, dst_prefix, suffix)
    dst_path = path.join(dst_dir, dst_file)

    create_thumbnail(src_path, dst_path)
    logger.info('wrote thumbnail: %s' % dst_file)

    for alias_seq in inv_aliases.get(seq, ()):
      alias_file = sequence_to_filename(alias_seq, dst_prefix, suffix)
      alias_path = path.join(dst_dir, alias_file)
      shutil.copy2(dst_path, alias_path)
      logger.info('wrote alias: %s' % alias_file)


def main():
  parser = argparse.ArgumentParser()
  parser.add_argument(
      '-s', '--src_dir', help='source images', metavar='dir', required=True)
  parser.add_argument(
      '-d', '--dst_dir', help='destination directory', metavar='dir',
      required=True)
  parser.add_argument(
      '-p', '--prefix', help='prefix for thumbnail', metavar='str',
      default='android_')
  parser.add_argument(
      '-v', '--verbose', help='write log output', metavar='level',
      choices='warning info debug'.split(), const='info',
      nargs='?')
  args = parser.parse_args()

  if args.verbose is not None:
    logging.basicConfig(level=getattr(logging, args.verbose.upper()))

  create_thumbnails_and_aliases(
      args.src_dir, args.dst_dir, args.prefix)


if __name__ == '__main__':
  main()