rebaseline_server: use new intermediate JSON format

gm/rebaseline_server/imagediffdb.py

 #!/usr/bin/python
 
 """
 Copyright 2013 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 Calulate differences between image pairs, and store them in a database.
 """
@@ skipping 25 matching lines @@
 DEFAULT_IMAGE_SUFFIX = '.png'
 DEFAULT_IMAGES_SUBDIR = 'images'
 
 DISALLOWED_FILEPATH_CHAR_REGEX = re.compile('[^\w\-]')
 
 DIFFS_SUBDIR = 'diffs'
 WHITEDIFFS_SUBDIR = 'whitediffs'
 
 VALUES_PER_BAND = 256
 
+# Keys used within DiffRecord dictionary representations.
+# Keep these in sync with static/constants.js
+KEY__DIFFERENCE_DATA__MAX_DIFF_PER_CHANNEL = 'maxDiffPerChannel'
+KEY__DIFFERENCE_DATA__NUM_DIFF_PIXELS = 'numDifferingPixels'
+KEY__DIFFERENCE_DATA__PERCENT_DIFF_PIXELS = 'percentDifferingPixels'
+KEY__DIFFERENCE_DATA__PERCEPTUAL_DIFF = 'perceptualDifference'
+KEY__DIFFERENCE_DATA__WEIGHTED_DIFF = 'weightedDiffMeasure'
+
 
 class DiffRecord(object):
   """ Record of differences between two images. """
 
   def __init__(self, storage_root,
                expected_image_url, expected_image_locator,
                actual_image_url, actual_image_locator,
                expected_images_subdir=DEFAULT_IMAGES_SUBDIR,
                actual_images_subdir=DEFAULT_IMAGES_SUBDIR,
                image_suffix=DEFAULT_IMAGE_SUFFIX):
@@ skipping 123 matching lines @@
 
   def get_max_diff_per_channel(self):
     """Returns the maximum difference between the expected and actual images
     for each R/G/B channel, as a list."""
     return self._max_diff_per_channel
 
   def as_dict(self):
     """Returns a dictionary representation of this DiffRecord, as needed when
     constructing the JSON representation."""
     return {
-        'numDifferingPixels': self._num_pixels_differing,
-        'percentDifferingPixels': self.get_percent_pixels_differing(),
-        'weightedDiffMeasure': self.get_weighted_diff_measure(),
-        'maxDiffPerChannel': self._max_diff_per_channel,
+        KEY__DIFFERENCE_DATA__NUM_DIFF_PIXELS: self._num_pixels_differing,
+        KEY__DIFFERENCE_DATA__PERCENT_DIFF_PIXELS:
+            self.get_percent_pixels_differing(),
+        KEY__DIFFERENCE_DATA__WEIGHTED_DIFF: self.get_weighted_diff_measure(),
+        KEY__DIFFERENCE_DATA__MAX_DIFF_PER_CHANNEL: self._max_diff_per_channel,
+        KEY__DIFFERENCE_DATA__PERCEPTUAL_DIFF: self._perceptual_difference,
     }
 
 
 class ImageDiffDB(object):
   """ Calculates differences between image pairs, maintaining a database of
   them for download."""
 
   def __init__(self, storage_root):
     """
     Args:
@@ skipping 188 matching lines @@
 
   Args:
     locator: string, or something that can be represented as a string
   """
   return DISALLOWED_FILEPATH_CHAR_REGEX.sub('_', str(locator))
 
 def _get_difference_locator(expected_image_locator, actual_image_locator):
   """Returns the locator string used to look up the diffs between expected_image
   and actual_image.
 
+  We must keep this function in sync with getImageDiffRelativeUrl() in
+  static/loader.js
+
   Args:
     expected_image_locator: locator string pointing at expected image
     actual_image_locator: locator string pointing at actual image
 
   Returns: already-sanitized locator where the diffs between expected and
       actual images can be found
   """
   return "%s-vs-%s" % (_sanitize_locator(expected_image_locator),
                        _sanitize_locator(actual_image_locator))