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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 ensure_same_mode(im1, im2): | |
26 # if both images already have the same mode (and palette, in | |
27 # case of mode P), don't convert anything. Images with mode P, | |
28 # and a different palette, are the only case where images | |
29 # using the same mode, will be incompatible with each other. | |
30 if im1.mode == im2.mode and (im1.mode != 'P' or im1.getpalette() == im2.getpal
ette()): | |
31 return (im1, im2) | |
32 | |
33 # if any given image has a mode that supports colors convert both | |
34 # images to RGB or RGBA, otherwise convert both images to L or LA. | |
35 # If any given image has an alpha channel (or mode P which | |
36 # can store transparent pixels too) convert both images | |
37 # to RGBA or LA, otherwise convert both images to RGB or L. | |
38 mode = max( | |
39 Image.getmodebase(im1.mode), | |
40 Image.getmodebase(im2.mode), | |
41 | |
42 key=('L', 'RGB').index | |
43 ) | |
44 | |
45 if any(im.mode in ('RGBA', 'LA', 'P') for im in (im1, im2)): | |
46 mode += 'A' | |
47 | |
48 return ( | |
49 im1 if im1.mode == mode else im1.convert(mode), | |
50 im2 if im2.mode == mode else im2.convert(mode), | |
51 ) | |
52 | |
53 def filter_contrastToAlpha(image, baseDir): | |
54 # In order to generate an alpha channel for images using a palette, we must | |
55 # convert the image to RGBA. It's important to use RGBA, not LA (grayscale+alp
ha), | |
56 # since PIL can't reliably convert P to LA. Also initially, we created an | |
57 # alpha channel by replacing opaque pixels with a high mark and transparent | |
58 # pixels with a low mark. However, it turned out that you can't rely on the | |
59 # value of Image.info['transparency'] since in case the transparency is | |
60 # specified in bytes (pngout loves to do that), we can't associate that value | |
61 # with transparent pixels. Moreover, some versions of PIL raise a warning | |
62 # when such images are pasted into another image. | |
63 if image.mode == 'P' and 'transparency' in image.info: | |
64 image = image.convert('RGBA') | |
65 | |
66 # Image.paste() ignores the alpha channel of the pasted image, but expects | |
67 # the mask to be passed as separate argument. So we have to extract the alpha | |
68 # channel (if any) from the image we are going to paste. | |
69 if image.mode in ('RGBA', 'LA'): | |
70 mask = image.split()[image.getbands().index('A')] | |
71 else: | |
72 mask = None | |
73 | |
74 alpha = Image.new('L', image.size, 255) | |
75 alpha.paste(image, mask=mask) | |
76 alpha = ImageOps.invert(alpha) | |
77 alpha = ImageOps.autocontrast(alpha) | |
78 | |
79 return Image.merge('LA', [Image.new('L', image.size), alpha]) | |
80 | |
81 def filter_blend(image, baseDir, filename, opacity): | |
82 image, overlay = ensure_same_mode( | |
83 image, | |
84 load_image(os.path.join( | |
85 baseDir, | |
86 *filename.split('/') | |
87 )) | |
88 ) | |
89 | |
90 return Image.blend(image, overlay, float(opacity)) | |
91 | |
92 def convertImages(params, files): | |
93 metadata = params['metadata'] | |
94 | |
95 for filename, chain in metadata.items('convert_img'): | |
96 baseDir = os.path.dirname(metadata.option_source('convert_img', filename)) | |
97 steps = re.split(r'\s*->\s*', chain) | |
98 image = load_image(os.path.join(baseDir, *steps.pop(0).split('/'))) | |
99 | |
100 for step in steps: | |
101 filter, args = re.match(r'([^(]+)(?:\((.*)\))?', step).groups() | |
102 args = re.split(r'\s*,\s*', args) if args else () | |
103 image = globals()['filter_' + filter](image, baseDir, *args) | |
104 | |
105 file = image_to_file(image, filename) | |
106 try: | |
107 files[filename] = file.read() | |
108 finally: | |
109 file.close() | |
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