Prepared buildtools for Safari

imageConversion.py

 # coding: utf-8
 
 # This file is part of the Adblock Plus build tools,
 # Copyright (C) 2006-2013 Eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
 import re
 from StringIO import StringIO
 
 import PIL.Image
-import PIL.ImageOps
 
 def get_alpha(image):
   if image.mode in ('RGBA', 'LA'):
     return image.split()[image.getbands().index('A')]
 
-  # images with palette doesn't have an alpha channel, but
-  # can store transparent pixels by using 0 as image data.
-  # In order to don't discard those information, we create an
-  # alpha channel from all the pixels that are not transparent.
   if image.mode == 'P':
-    return image.point([0] + [255] * 255, 'L')
+    transparency = image.info.get('transparency')
+
+    if transparency is not None:
+      table = [255] * 256
+      table[transparency] = 0
+
+      return image.point(table, 'L')
 
 def ensure_same_mode(im1, im2):
   # if both images already have the same mode (and palette, in
   # case of mode P), don't convert anything. Images with mode P,
   # and a different palette, are the only case where images
   # using the same mode, will be incompatible with each other.
   if im1.mode == im2.mode and (im1.mode != 'P' or im1.getpalette() == im2.getpalette()):
     return (im1, im2)
 
   # if any given image has a mode that supports colors convert both
@@ skipping 19 matching lines @@
 def filter_grayscale(image, baseDir):
   alpha = get_alpha(image)
   image = image.convert('L')
 
   if alpha:
     image.putalpha(alpha)
 
   return image
 
 def filter_contrastToAlpha(image, baseDir):
+  import PIL.ImageOps
+
   alpha = PIL.Image.new('L', image.size, 255)
   alpha.paste(image, mask=get_alpha(image))
   alpha = PIL.ImageOps.invert(alpha)
   alpha = PIL.ImageOps.autocontrast(alpha)
 
   return PIL.Image.merge('LA', [PIL.Image.new('L', image.size), alpha])
 
 def filter_blend(image, baseDir, *args):
   if len(args) == 2:
     filename, opacity = args
@@ skipping 30 matching lines @@
 
     for step in steps:
       filter, args = re.match(r'([^(]+)(?:\((.*)\))?', step).groups()
       args = re.split(r'\s*,\s*', args) if args else ()
       image = globals()['filter_' + filter](image, baseDir, *args)
 
     f = StringIO()
     f.name = filename
     image.save(f)
     files[filename] = f.getvalue()