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| 1 # coding: utf-8 |  | 
| 2 |  | 
| 3 # This Source Code Form is subject to the terms of the Mozilla Public |  | 
| 4 # License, v. 2.0. If a copy of the MPL was not distributed with this |  | 
| 5 # file, You can obtain one at http://mozilla.org/MPL/2.0/. |  | 
| 6 |  | 
| 7 import os |  | 
| 8 import re |  | 
| 9 |  | 
| 10 try: |  | 
| 11   from PIL import Image |  | 
| 12   from PIL import ImageOps |  | 
| 13 except ImportError: |  | 
| 14   import Image |  | 
| 15   import ImageOps |  | 
| 16 |  | 
| 17 from imageCompression import image_to_file |  | 
| 18 |  | 
| 19 def load_image(path): |  | 
| 20   image = Image.open(path) |  | 
| 21   # Make sure the image is loaded, some versions of PIL load images lazily. |  | 
| 22   image.load() |  | 
| 23   return image |  | 
| 24 |  | 
| 25 def filter_contrastToAlpha(image, baseDir): |  | 
| 26   # In order to generate an alpha channel for images using a palette, we must |  | 
| 27   # convert the image to RGBA. It's important to use RGBA, not LA (grayscale+alp
    ha), |  | 
| 28   # since PIL can't reliably convert P to LA. Also initially, we created an |  | 
| 29   # alpha channel by replacing opaque pixels with a high mark and transparent |  | 
| 30   # pixels with a low mark. However, it turned out that you can't rely on the |  | 
| 31   # value of Image.info['transparency'] since in case the transparency is |  | 
| 32   # specified in bytes (pngout loves to do that), we can't associate that value |  | 
| 33   # with transparent pixels. Moreover, some versions of PIL raise a warning |  | 
| 34   # when such images are pasted into another image. |  | 
| 35   if image.mode == 'P' and 'transparency' in image.info: |  | 
| 36     image = image.convert('RGBA') |  | 
| 37 |  | 
| 38   # Image.paste() ignores the alpha channel of the pasted image, but expects |  | 
| 39   # the mask to be passed as separate argument. So we have to extract the alpha |  | 
| 40   # channel (if any) from the image we are going to paste. |  | 
| 41   if image.mode in ('RGBA', 'LA'): |  | 
| 42     mask = image.split()[image.getbands().index('A')] |  | 
| 43   else: |  | 
| 44     mask = None |  | 
| 45 |  | 
| 46   alpha = Image.new('L', image.size, 255) |  | 
| 47   alpha.paste(image, mask=mask) |  | 
| 48   alpha = ImageOps.invert(alpha) |  | 
| 49   alpha = ImageOps.autocontrast(alpha) |  | 
| 50 |  | 
| 51   return Image.merge('LA', [Image.new('L', image.size), alpha]) |  | 
| 52 |  | 
| 53 def convertImages(params, files): |  | 
| 54   metadata = params['metadata'] |  | 
| 55 |  | 
| 56   for filename, chain in metadata.items('convert_img'): |  | 
| 57     baseDir = os.path.dirname(metadata.option_source('convert_img', filename)) |  | 
| 58     steps = re.split(r'\s*->\s*', chain) |  | 
| 59     image = load_image(os.path.join(baseDir, *steps.pop(0).split('/'))) |  | 
| 60 |  | 
| 61     for step in steps: |  | 
| 62       filter, args = re.match(r'([^(]+)(?:\((.*)\))?', step).groups() |  | 
| 63       args = re.split(r'\s*,\s*', args) if args else () |  | 
| 64       image = globals()['filter_' + filter](image, baseDir, *args) |  | 
| 65 |  | 
| 66     file = image_to_file(image, filename) |  | 
| 67     try: |  | 
| 68       files[filename] = file.read() |  | 
| 69     finally: |  | 
| 70       file.close() |  | 
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