Update thumbnail generation and add unknown flag sequences.

Thumbnail generation for Unicode requires some changes:
- 72x72 images (exact, not just fit within that frame)
- custom prefix ending in underscore
- images for unsupported flags

The default build doesn't support some flags by default, since they
are not wanted by Android.  For the thumbnail list these images need
to be provided, so we alias them to the unknown flag images as that's
what would show for them.  It's probably a good idea to list these
explicitly anyway, other tools could use this information.

generate_emoji_thumbnails.py

@@ -32,75 +32,86 @@ 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
-  subprocess.check_call(['convert', '-resize', '72x72', src_path, dst_path])
-  logger.info('wrote thumbnail: %s' % dst_path)
+  # 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])
 
 
-_INV_ALIASES = None
 def get_inv_aliases():
-  global _INV_ALIASES
-  if _INV_ALIASES is None:
-    aliases = add_aliases.read_default_emoji_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)
-    for k, v in aliases.iteritems():
+
+  standard_aliases = add_aliases.read_default_emoji_aliases()
+  for k, v in standard_aliases.iteritems():
     inv_aliases[v].append(k)
-    _INV_ALIASES = inv_aliases
-  return _INV_ALIASES
+
+  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 is_emoji_filename(filename):
-  return filename.startswith('emoji_u') and filename.endswith('.png')
+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 check_emoji_filename(filename):
-  if not is_emoji_filename(filename):
-    raise ValueError('not an emoji image file: %s' % filename)
+def sequence_to_filename(seq, prefix, suffix):
+  return ''.join((prefix, unicode_data.seq_to_string(seq), suffix))
 
 
-def emoji_filename_to_sequence(filename):
-  check_emoji_filename(filename)
+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'."""
 
-  return tuple([
-      int(s, 16) for s in filename[7:-4].split('_')
-      if s.lower() != 'fe0f'])
-
-
-def sequence_to_emoji_filename(seq):
-  return 'emoji_u%s.png' % '_'.join('%04x' % n for n in seq)
-
-
-def create_emoji_alias(src_path, dst_dir):
-  """If src_path is a target of any emoji aliases, create a copy in dst_dir
-  named for each alias."""
-  src_file = path.basename(src_path)
-  seq = emoji_filename_to_sequence(src_file)
-
-  inv_aliases = get_inv_aliases()
-  if seq in inv_aliases:
-    for alias_seq in inv_aliases[seq]:
-      alias_file = sequence_to_emoji_filename(alias_seq)
-      shutil.copy2(src_path, path.join(dst_dir, alias_file))
-      logger.info('wrote alias %s (copy of %s)' % (alias_file, src_file))
-
-
-def create_thumbnails_and_aliases(src_dir, dst_dir):
   if not path.isdir(src_dir):
     raise ValueError('"%s" is not a directory')
   dst_dir = tool_utils.ensure_dir_exists(dst_dir)
 
-  for f in os.listdir(src_dir):
-    if not (f.startswith('emoji_u') and f.endswith('.png')):
-      logger.warning('skipping "%s"' % f)
+  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.join(src_dir, f)
-    dst = path.join(dst_dir, f)
-    create_thumbnail(src, dst)
-    create_emoji_alias(dst, dst_dir)
+
+    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():
@@ -110,6 +121,9 @@ def main():
   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',
@@ -119,7 +133,8 @@ def main():
   if args.verbose is not None:
     logging.basicConfig(level=getattr(logging, args.verbose.upper()))
 
-  create_thumbnails_and_aliases(args.src_dir, args.dst_dir)
+  create_thumbnails_and_aliases(
+      args.src_dir, args.dst_dir, args.prefix)
 
 
 if __name__ == '__main__':

unknown_flag_aliases.txt

@@ -0,0 +1,25 @@
+# alias table
+# from;to
+# the 'from' sequence should be represented by the image for the 'to' sequence
+# these are flags we explicitly omit
+
+# flag aliases
+1f1e7_1f1f1;fe82b # BL
+1f1e7_1f1f6;fe82b # BQ
+1f1e9_1f1ec;fe82b # DG
+1f1ea_1f1e6;fe82b # EA
+1f1ea_1f1ed;fe82b # EH
+1f1eb_1f1f0;fe82b # FK
+1f1ec_1f1eb;fe82b # GF
+1f1ec_1f1f5;fe82b # GP
+1f1ec_1f1f8;fe82b # GS
+1f1f2_1f1eb;fe82b # MF
+1f1f2_1f1f6;fe82b # MQ
+1f1f3_1f1e8;fe82b # NC
+1f1f5_1f1f2;fe82b # PM
+1f1f7_1f1ea;fe82b # RE
+1f1f9_1f1eb;fe82b # TF
+1f1fc_1f1eb;fe82b # WF
+1f1fd_1f1f0;fe82b # XK
+1f1fe_1f1f9;fe82b # YT
+