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1 #!/usr/bin/python | 1 #!/usr/bin/python |
2 | 2 |
3 """ | 3 """ |
4 Copyright 2013 Google Inc. | 4 Copyright 2013 Google Inc. |
5 | 5 |
6 Use of this source code is governed by a BSD-style license that can be | 6 Use of this source code is governed by a BSD-style license that can be |
7 found in the LICENSE file. | 7 found in the LICENSE file. |
8 | 8 |
9 Calulate differences between image pairs, and store them in a database. | 9 Calulate differences between image pairs, and store them in a database. |
10 """ | 10 """ |
11 | 11 |
12 import contextlib | 12 import contextlib |
13 import csv | 13 import json |
14 import logging | 14 import logging |
15 import os | 15 import os |
16 import re | 16 import re |
17 import shutil | 17 import shutil |
18 import sys | 18 import sys |
19 import tempfile | 19 import tempfile |
20 import urllib | 20 import urllib |
21 try: | |
22 from PIL import Image, ImageChops | |
23 except ImportError: | |
24 raise ImportError('Requires PIL to be installed; see ' | |
25 + 'http://www.pythonware.com/products/pil/') | |
26 | 21 |
27 # Set the PYTHONPATH to include the tools directory. | 22 # Set the PYTHONPATH to include the tools directory. |
28 sys.path.append( | 23 sys.path.append( |
29 os.path.join( | 24 os.path.join( |
30 os.path.dirname(os.path.realpath(__file__)), os.pardir, os.pardir, | 25 os.path.dirname(os.path.realpath(__file__)), os.pardir, os.pardir, |
31 'tools')) | 26 'tools')) |
32 import find_run_binary | 27 import find_run_binary |
33 | 28 |
34 SKPDIFF_BINARY = find_run_binary.find_path_to_program('skpdiff') | 29 SKPDIFF_BINARY = find_run_binary.find_path_to_program('skpdiff') |
35 | 30 |
36 DEFAULT_IMAGE_SUFFIX = '.png' | 31 DEFAULT_IMAGE_SUFFIX = '.png' |
37 DEFAULT_IMAGES_SUBDIR = 'images' | 32 DEFAULT_IMAGES_SUBDIR = 'images' |
38 | 33 |
39 DISALLOWED_FILEPATH_CHAR_REGEX = re.compile('[^\w\-]') | 34 DISALLOWED_FILEPATH_CHAR_REGEX = re.compile('[^\w\-]') |
40 | 35 |
41 DIFFS_SUBDIR = 'diffs' | 36 RGBDIFFS_SUBDIR = 'diffs' |
42 WHITEDIFFS_SUBDIR = 'whitediffs' | 37 WHITEDIFFS_SUBDIR = 'whitediffs' |
43 | 38 |
44 VALUES_PER_BAND = 256 | |
45 | |
46 # Keys used within DiffRecord dictionary representations. | 39 # Keys used within DiffRecord dictionary representations. |
47 # NOTE: Keep these in sync with static/constants.js | 40 # NOTE: Keep these in sync with static/constants.js |
48 KEY__DIFFERENCES__MAX_DIFF_PER_CHANNEL = 'maxDiffPerChannel' | 41 KEY__DIFFERENCES__MAX_DIFF_PER_CHANNEL = 'maxDiffPerChannel' |
49 KEY__DIFFERENCES__NUM_DIFF_PIXELS = 'numDifferingPixels' | 42 KEY__DIFFERENCES__NUM_DIFF_PIXELS = 'numDifferingPixels' |
50 KEY__DIFFERENCES__PERCENT_DIFF_PIXELS = 'percentDifferingPixels' | 43 KEY__DIFFERENCES__PERCENT_DIFF_PIXELS = 'percentDifferingPixels' |
51 KEY__DIFFERENCES__PERCEPTUAL_DIFF = 'perceptualDifference' | 44 KEY__DIFFERENCES__PERCEPTUAL_DIFF = 'perceptualDifference' |
52 | 45 |
53 | 46 |
54 class DiffRecord(object): | 47 class DiffRecord(object): |
55 """ Record of differences between two images. """ | 48 """ Record of differences between two images. """ |
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80 actual image within storage_root (probably including a checksum to | 73 actual image within storage_root (probably including a checksum to |
81 guarantee uniqueness) | 74 guarantee uniqueness) |
82 expected_images_subdir: the subdirectory expected images are stored in. | 75 expected_images_subdir: the subdirectory expected images are stored in. |
83 actual_images_subdir: the subdirectory actual images are stored in. | 76 actual_images_subdir: the subdirectory actual images are stored in. |
84 image_suffix: the suffix of images. | 77 image_suffix: the suffix of images. |
85 """ | 78 """ |
86 expected_image_locator = _sanitize_locator(expected_image_locator) | 79 expected_image_locator = _sanitize_locator(expected_image_locator) |
87 actual_image_locator = _sanitize_locator(actual_image_locator) | 80 actual_image_locator = _sanitize_locator(actual_image_locator) |
88 | 81 |
89 # Download the expected/actual images, if we don't have them already. | 82 # Download the expected/actual images, if we don't have them already. |
90 # TODO(rmistry): Add a parameter that makes _download_and_open_image raise | 83 # TODO(rmistry): Add a parameter that just tries to use already-present |
91 # an exception if images are not found locally (instead of trying to | 84 # image files rather than downloading them. |
92 # download them). | |
93 expected_image_file = os.path.join( | 85 expected_image_file = os.path.join( |
94 storage_root, expected_images_subdir, | 86 storage_root, expected_images_subdir, |
95 str(expected_image_locator) + image_suffix) | 87 str(expected_image_locator) + image_suffix) |
96 actual_image_file = os.path.join( | 88 actual_image_file = os.path.join( |
97 storage_root, actual_images_subdir, | 89 storage_root, actual_images_subdir, |
98 str(actual_image_locator) + image_suffix) | 90 str(actual_image_locator) + image_suffix) |
99 try: | 91 try: |
100 expected_image = _download_and_open_image( | 92 _download_file(expected_image_file, expected_image_url) |
101 expected_image_file, expected_image_url) | |
102 except Exception: | 93 except Exception: |
103 logging.exception('unable to download expected_image_url %s to file %s' % | 94 logging.exception('unable to download expected_image_url %s to file %s' % |
104 (expected_image_url, expected_image_file)) | 95 (expected_image_url, expected_image_file)) |
105 raise | 96 raise |
106 try: | 97 try: |
107 actual_image = _download_and_open_image( | 98 _download_file(actual_image_file, actual_image_url) |
108 actual_image_file, actual_image_url) | |
109 except Exception: | 99 except Exception: |
110 logging.exception('unable to download actual_image_url %s to file %s' % | 100 logging.exception('unable to download actual_image_url %s to file %s' % |
111 (actual_image_url, actual_image_file)) | 101 (actual_image_url, actual_image_file)) |
112 raise | 102 raise |
113 | 103 |
114 # Generate the diff image (absolute diff at each pixel) and | 104 # Get all diff images and values from skpdiff binary. |
115 # max_diff_per_channel. | 105 skpdiff_output_dir = tempfile.mkdtemp() |
116 diff_image = _generate_image_diff(actual_image, expected_image) | |
117 diff_histogram = diff_image.histogram() | |
118 (diff_width, diff_height) = diff_image.size | |
119 self._max_diff_per_channel = _max_per_band(diff_histogram) | |
120 | |
121 # Generate the whitediff image (any differing pixels show as white). | |
122 # This is tricky, because when you convert color images to grayscale or | |
123 # black & white in PIL, it has its own ideas about thresholds. | |
124 # We have to force it: if a pixel has any color at all, it's a '1'. | |
125 bands = diff_image.split() | |
126 graydiff_image = ImageChops.lighter(ImageChops.lighter( | |
127 bands[0], bands[1]), bands[2]) | |
128 whitediff_image = (graydiff_image.point(lambda p: p > 0 and VALUES_PER_BAND) | |
129 .convert('1', dither=Image.NONE)) | |
130 | |
131 # Calculate the perceptual difference percentage. | |
132 skpdiff_csv_dir = tempfile.mkdtemp() | |
133 try: | 106 try: |
134 skpdiff_csv_output = os.path.join(skpdiff_csv_dir, 'skpdiff-output.csv') | 107 skpdiff_summary_file = os.path.join(skpdiff_output_dir, |
| 108 'skpdiff-output.json') |
| 109 skpdiff_rgbdiff_dir = os.path.join(skpdiff_output_dir, 'rgbDiff') |
| 110 skpdiff_whitediff_dir = os.path.join(skpdiff_output_dir, 'whiteDiff') |
135 expected_img = os.path.join(storage_root, expected_images_subdir, | 111 expected_img = os.path.join(storage_root, expected_images_subdir, |
136 str(expected_image_locator) + image_suffix) | 112 str(expected_image_locator) + image_suffix) |
137 actual_img = os.path.join(storage_root, actual_images_subdir, | 113 actual_img = os.path.join(storage_root, actual_images_subdir, |
138 str(actual_image_locator) + image_suffix) | 114 str(actual_image_locator) + image_suffix) |
| 115 |
| 116 # TODO: Call skpdiff ONCE for all image pairs, instead of calling it |
| 117 # repeatedly. This will allow us to parallelize a lot more work. |
139 find_run_binary.run_command( | 118 find_run_binary.run_command( |
140 [SKPDIFF_BINARY, '-p', expected_img, actual_img, | 119 [SKPDIFF_BINARY, '-p', expected_img, actual_img, |
141 '--csv', skpdiff_csv_output, '-d', 'perceptual']) | 120 '--jsonp', 'false', |
142 with contextlib.closing(open(skpdiff_csv_output)) as csv_file: | 121 '--output', skpdiff_summary_file, |
143 for row in csv.DictReader(csv_file): | 122 '--differs', 'perceptual', 'different_pixels', |
144 perceptual_similarity = float(row[' perceptual'].strip()) | 123 '--rgbDiffDir', skpdiff_rgbdiff_dir, |
145 if not 0 <= perceptual_similarity <= 1: | 124 '--whiteDiffDir', skpdiff_whitediff_dir, |
146 # skpdiff outputs -1 if the images are different sizes. Treat any | 125 ]) |
147 # output that does not lie in [0, 1] as having 0% perceptual | 126 |
148 # similarity. | 127 # Get information out of the skpdiff_summary_file. |
149 perceptual_similarity = 0 | 128 with contextlib.closing(open(skpdiff_summary_file)) as fp: |
150 # skpdiff returns the perceptual similarity, convert it to get the | 129 data = json.load(fp) |
151 # perceptual difference percentage. | 130 |
152 self._perceptual_difference = 100 - (perceptual_similarity * 100) | 131 # For now, we can assume there is only one record in the output summary, |
| 132 # since we passed skpdiff only one pair of images. |
| 133 record = data['records'][0] |
| 134 self._width = record['width'] |
| 135 self._height = record['height'] |
| 136 # TODO: make max_diff_per_channel a tuple instead of a list, because the |
| 137 # structure is meaningful (first element is red, second is green, etc.) |
| 138 # See http://stackoverflow.com/a/626871 |
| 139 self._max_diff_per_channel = [ |
| 140 record['maxRedDiff'], record['maxGreenDiff'], record['maxBlueDiff']] |
| 141 rgb_diff_path = record['rgbDiffPath'] |
| 142 white_diff_path = record['whiteDiffPath'] |
| 143 per_differ_stats = record['diffs'] |
| 144 for stats in per_differ_stats: |
| 145 differ_name = stats['differName'] |
| 146 if differ_name == 'different_pixels': |
| 147 self._num_pixels_differing = stats['pointsOfInterest'] |
| 148 elif differ_name == 'perceptual': |
| 149 perceptual_similarity = stats['result'] |
| 150 |
| 151 # skpdiff returns the perceptual similarity; convert it to get the |
| 152 # perceptual difference percentage. |
| 153 # skpdiff outputs -1 if the images are different sizes. Treat any |
| 154 # output that does not lie in [0, 1] as having 0% perceptual |
| 155 # similarity. |
| 156 if not 0 <= perceptual_similarity <= 1: |
| 157 perceptual_similarity = 0 |
| 158 self._perceptual_difference = 100 - (perceptual_similarity * 100) |
| 159 |
| 160 # Store the rgbdiff and whitediff images generated above. |
| 161 diff_image_locator = _get_difference_locator( |
| 162 expected_image_locator=expected_image_locator, |
| 163 actual_image_locator=actual_image_locator) |
| 164 basename = str(diff_image_locator) + image_suffix |
| 165 _mkdir_unless_exists(os.path.join(storage_root, RGBDIFFS_SUBDIR)) |
| 166 _mkdir_unless_exists(os.path.join(storage_root, WHITEDIFFS_SUBDIR)) |
| 167 # TODO: Modify skpdiff's behavior so we can tell it exactly where to |
| 168 # write the image files into, rather than having to move them around |
| 169 # after skpdiff writes them out. |
| 170 shutil.copyfile(rgb_diff_path, |
| 171 os.path.join(storage_root, RGBDIFFS_SUBDIR, basename)) |
| 172 shutil.copyfile(white_diff_path, |
| 173 os.path.join(storage_root, WHITEDIFFS_SUBDIR, basename)) |
| 174 |
153 finally: | 175 finally: |
154 shutil.rmtree(skpdiff_csv_dir) | 176 shutil.rmtree(skpdiff_output_dir) |
155 | |
156 # Final touches on diff_image: use whitediff_image as an alpha mask. | |
157 # Unchanged pixels are transparent; differing pixels are opaque. | |
158 diff_image.putalpha(whitediff_image) | |
159 | |
160 # Store the diff and whitediff images generated above. | |
161 diff_image_locator = _get_difference_locator( | |
162 expected_image_locator=expected_image_locator, | |
163 actual_image_locator=actual_image_locator) | |
164 basename = str(diff_image_locator) + image_suffix | |
165 _save_image(diff_image, os.path.join( | |
166 storage_root, DIFFS_SUBDIR, basename)) | |
167 _save_image(whitediff_image, os.path.join( | |
168 storage_root, WHITEDIFFS_SUBDIR, basename)) | |
169 | |
170 # Calculate difference metrics. | |
171 (self._width, self._height) = diff_image.size | |
172 self._num_pixels_differing = ( | |
173 whitediff_image.histogram()[VALUES_PER_BAND - 1]) | |
174 | 177 |
175 def get_num_pixels_differing(self): | 178 def get_num_pixels_differing(self): |
176 """Returns the absolute number of pixels that differ.""" | 179 """Returns the absolute number of pixels that differ.""" |
177 return self._num_pixels_differing | 180 return self._num_pixels_differing |
178 | 181 |
179 def get_percent_pixels_differing(self): | 182 def get_percent_pixels_differing(self): |
180 """Returns the percentage of pixels that differ, as a float between | 183 """Returns the percentage of pixels that differ, as a float between |
181 0 and 100 (inclusive).""" | 184 0 and 100 (inclusive).""" |
182 return ((float(self._num_pixels_differing) * 100) / | 185 return ((float(self._num_pixels_differing) * 100) / |
183 (self._width * self._height)) | 186 (self._width * self._height)) |
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271 | 274 |
272 Raises a KeyError if we don't have a DiffRecord for this image pair. | 275 Raises a KeyError if we don't have a DiffRecord for this image pair. |
273 """ | 276 """ |
274 key = (_sanitize_locator(expected_image_locator), | 277 key = (_sanitize_locator(expected_image_locator), |
275 _sanitize_locator(actual_image_locator)) | 278 _sanitize_locator(actual_image_locator)) |
276 return self._diff_dict[key] | 279 return self._diff_dict[key] |
277 | 280 |
278 | 281 |
279 # Utility functions | 282 # Utility functions |
280 | 283 |
281 def _max_per_band(histogram): | 284 def _download_file(local_filepath, url): |
282 """Given the histogram of an image, return the maximum value of each band | 285 """Download a file from url to local_filepath, unless it is already there. |
283 (a.k.a. "color channel", such as R/G/B) across the entire image. | |
284 | |
285 Args: | |
286 histogram: PIL histogram | |
287 | |
288 Returns the maximum value of each band within the image histogram, as a list. | |
289 """ | |
290 max_per_band = [] | |
291 assert(len(histogram) % VALUES_PER_BAND == 0) | |
292 num_bands = len(histogram) / VALUES_PER_BAND | |
293 for band in xrange(num_bands): | |
294 # Assuming that VALUES_PER_BAND is 256... | |
295 # the 'R' band makes up indices 0-255 in the histogram, | |
296 # the 'G' band makes up indices 256-511 in the histogram, | |
297 # etc. | |
298 min_index = band * VALUES_PER_BAND | |
299 index = min_index + VALUES_PER_BAND | |
300 while index > min_index: | |
301 index -= 1 | |
302 if histogram[index] > 0: | |
303 max_per_band.append(index - min_index) | |
304 break | |
305 return max_per_band | |
306 | |
307 | |
308 def _generate_image_diff(image1, image2): | |
309 """Wrapper for ImageChops.difference(image1, image2) that will handle some | |
310 errors automatically, or at least yield more useful error messages. | |
311 | |
312 TODO(epoger): Currently, some of the images generated by the bots are RGBA | |
313 and others are RGB. I'm not sure why that is. For now, to avoid confusion | |
314 within the UI, convert all to RGB when diffing. | |
315 | |
316 Args: | |
317 image1: a PIL image object | |
318 image2: a PIL image object | |
319 | |
320 Returns: per-pixel diffs between image1 and image2, as a PIL image object | |
321 """ | |
322 try: | |
323 return ImageChops.difference(image1.convert('RGB'), image2.convert('RGB')) | |
324 except ValueError: | |
325 logging.error('Error diffing image1 [%s] and image2 [%s].' % ( | |
326 repr(image1), repr(image2))) | |
327 raise | |
328 | |
329 | |
330 def _download_and_open_image(local_filepath, url): | |
331 """Open the image at local_filepath; if there is no file at that path, | |
332 download it from url to that path and then open it. | |
333 | 286 |
334 Args: | 287 Args: |
335 local_filepath: path on local disk where the image should be stored | 288 local_filepath: path on local disk where the image should be stored |
336 url: URL from which we can download the image if we don't have it yet | 289 url: URL from which we can download the image if we don't have it yet |
337 | |
338 Returns: a PIL image object | |
339 """ | 290 """ |
340 if not os.path.exists(local_filepath): | 291 if not os.path.exists(local_filepath): |
341 _mkdir_unless_exists(os.path.dirname(local_filepath)) | 292 _mkdir_unless_exists(os.path.dirname(local_filepath)) |
342 with contextlib.closing(urllib.urlopen(url)) as url_handle: | 293 with contextlib.closing(urllib.urlopen(url)) as url_handle: |
343 with open(local_filepath, 'wb') as file_handle: | 294 with open(local_filepath, 'wb') as file_handle: |
344 shutil.copyfileobj(fsrc=url_handle, fdst=file_handle) | 295 shutil.copyfileobj(fsrc=url_handle, fdst=file_handle) |
345 return _open_image(local_filepath) | |
346 | |
347 | |
348 def _open_image(filepath): | |
349 """Wrapper for Image.open(filepath) that yields more useful error messages. | |
350 | |
351 Args: | |
352 filepath: path on local disk to load image from | |
353 | |
354 Returns: a PIL image object | |
355 """ | |
356 try: | |
357 return Image.open(filepath) | |
358 except IOError: | |
359 # If we are unable to load an image from the file, delete it from disk | |
360 # and we will try to fetch it again next time. Fixes http://skbug.com/2247 | |
361 logging.error('IOError loading image file %s ; deleting it.' % filepath) | |
362 os.remove(filepath) | |
363 raise | |
364 | |
365 | |
366 def _save_image(image, filepath, format='PNG'): | |
367 """Write an image to disk, creating any intermediate directories as needed. | |
368 | |
369 Args: | |
370 image: a PIL image object | |
371 filepath: path on local disk to write image to | |
372 format: one of the PIL image formats, listed at | |
373 http://effbot.org/imagingbook/formats.htm | |
374 """ | |
375 _mkdir_unless_exists(os.path.dirname(filepath)) | |
376 image.save(filepath, format) | |
377 | 296 |
378 | 297 |
379 def _mkdir_unless_exists(path): | 298 def _mkdir_unless_exists(path): |
380 """Unless path refers to an already-existing directory, create it. | 299 """Unless path refers to an already-existing directory, create it. |
381 | 300 |
382 Args: | 301 Args: |
383 path: path on local disk | 302 path: path on local disk |
384 """ | 303 """ |
385 if not os.path.isdir(path): | 304 if not os.path.isdir(path): |
386 os.makedirs(path) | 305 os.makedirs(path) |
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405 | 324 |
406 Args: | 325 Args: |
407 expected_image_locator: locator string pointing at expected image | 326 expected_image_locator: locator string pointing at expected image |
408 actual_image_locator: locator string pointing at actual image | 327 actual_image_locator: locator string pointing at actual image |
409 | 328 |
410 Returns: already-sanitized locator where the diffs between expected and | 329 Returns: already-sanitized locator where the diffs between expected and |
411 actual images can be found | 330 actual images can be found |
412 """ | 331 """ |
413 return "%s-vs-%s" % (_sanitize_locator(expected_image_locator), | 332 return "%s-vs-%s" % (_sanitize_locator(expected_image_locator), |
414 _sanitize_locator(actual_image_locator)) | 333 _sanitize_locator(actual_image_locator)) |
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