| #!/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. |
| """ |
| |
| import contextlib |
| import json |
| import logging |
| import os |
| import re |
| import shutil |
| import sys |
| import tempfile |
| import urllib |
| |
| # Set the PYTHONPATH to include the tools directory. |
| sys.path.append( |
| os.path.join( |
| os.path.dirname(os.path.realpath(__file__)), os.pardir, os.pardir, |
| 'tools')) |
| import find_run_binary |
| |
| SKPDIFF_BINARY = find_run_binary.find_path_to_program('skpdiff') |
| |
| DEFAULT_IMAGE_SUFFIX = '.png' |
| DEFAULT_IMAGES_SUBDIR = 'images' |
| |
| DISALLOWED_FILEPATH_CHAR_REGEX = re.compile('[^\w\-]') |
| |
| RGBDIFFS_SUBDIR = 'diffs' |
| WHITEDIFFS_SUBDIR = 'whitediffs' |
| |
| # Keys used within DiffRecord dictionary representations. |
| # NOTE: Keep these in sync with static/constants.js |
| KEY__DIFFERENCES__MAX_DIFF_PER_CHANNEL = 'maxDiffPerChannel' |
| KEY__DIFFERENCES__NUM_DIFF_PIXELS = 'numDifferingPixels' |
| KEY__DIFFERENCES__PERCENT_DIFF_PIXELS = 'percentDifferingPixels' |
| KEY__DIFFERENCES__PERCEPTUAL_DIFF = 'perceptualDifference' |
| |
| |
| 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): |
| """Download this pair of images (unless we already have them on local disk), |
| and prepare a DiffRecord for them. |
| |
| TODO(epoger): Make this asynchronously download images, rather than blocking |
| until the images have been downloaded and processed. |
| |
| Args: |
| storage_root: root directory on local disk within which we store all |
| images |
| expected_image_url: file or HTTP url from which we will download the |
| expected image |
| expected_image_locator: a unique ID string under which we will store the |
| expected image within storage_root (probably including a checksum to |
| guarantee uniqueness) |
| actual_image_url: file or HTTP url from which we will download the |
| actual image |
| actual_image_locator: a unique ID string under which we will store the |
| actual image within storage_root (probably including a checksum to |
| guarantee uniqueness) |
| expected_images_subdir: the subdirectory expected images are stored in. |
| actual_images_subdir: the subdirectory actual images are stored in. |
| image_suffix: the suffix of images. |
| """ |
| expected_image_locator = _sanitize_locator(expected_image_locator) |
| actual_image_locator = _sanitize_locator(actual_image_locator) |
| |
| # Download the expected/actual images, if we don't have them already. |
| # TODO(rmistry): Add a parameter that just tries to use already-present |
| # image files rather than downloading them. |
| expected_image_file = os.path.join( |
| storage_root, expected_images_subdir, |
| str(expected_image_locator) + image_suffix) |
| actual_image_file = os.path.join( |
| storage_root, actual_images_subdir, |
| str(actual_image_locator) + image_suffix) |
| try: |
| _download_file(expected_image_file, expected_image_url) |
| except Exception: |
| logging.exception('unable to download expected_image_url %s to file %s' % |
| (expected_image_url, expected_image_file)) |
| raise |
| try: |
| _download_file(actual_image_file, actual_image_url) |
| except Exception: |
| logging.exception('unable to download actual_image_url %s to file %s' % |
| (actual_image_url, actual_image_file)) |
| raise |
| |
| # Get all diff images and values from skpdiff binary. |
| skpdiff_output_dir = tempfile.mkdtemp() |
| try: |
| skpdiff_summary_file = os.path.join(skpdiff_output_dir, |
| 'skpdiff-output.json') |
| skpdiff_rgbdiff_dir = os.path.join(skpdiff_output_dir, 'rgbDiff') |
| skpdiff_whitediff_dir = os.path.join(skpdiff_output_dir, 'whiteDiff') |
| expected_img = os.path.join(storage_root, expected_images_subdir, |
| str(expected_image_locator) + image_suffix) |
| actual_img = os.path.join(storage_root, actual_images_subdir, |
| str(actual_image_locator) + image_suffix) |
| |
| # TODO: Call skpdiff ONCE for all image pairs, instead of calling it |
| # repeatedly. This will allow us to parallelize a lot more work. |
| find_run_binary.run_command( |
| [SKPDIFF_BINARY, '-p', expected_img, actual_img, |
| '--jsonp', 'false', |
| '--output', skpdiff_summary_file, |
| '--differs', 'perceptual', 'different_pixels', |
| '--rgbDiffDir', skpdiff_rgbdiff_dir, |
| '--whiteDiffDir', skpdiff_whitediff_dir, |
| ]) |
| |
| # Get information out of the skpdiff_summary_file. |
| with contextlib.closing(open(skpdiff_summary_file)) as fp: |
| data = json.load(fp) |
| |
| # For now, we can assume there is only one record in the output summary, |
| # since we passed skpdiff only one pair of images. |
| record = data['records'][0] |
| self._width = record['width'] |
| self._height = record['height'] |
| # TODO: make max_diff_per_channel a tuple instead of a list, because the |
| # structure is meaningful (first element is red, second is green, etc.) |
| # See http://stackoverflow.com/a/626871 |
| self._max_diff_per_channel = [ |
| record['maxRedDiff'], record['maxGreenDiff'], record['maxBlueDiff']] |
| rgb_diff_path = record['rgbDiffPath'] |
| white_diff_path = record['whiteDiffPath'] |
| per_differ_stats = record['diffs'] |
| for stats in per_differ_stats: |
| differ_name = stats['differName'] |
| if differ_name == 'different_pixels': |
| self._num_pixels_differing = stats['pointsOfInterest'] |
| elif differ_name == 'perceptual': |
| perceptual_similarity = stats['result'] |
| |
| # skpdiff returns the perceptual similarity; convert it to get the |
| # perceptual difference percentage. |
| # skpdiff outputs -1 if the images are different sizes. Treat any |
| # output that does not lie in [0, 1] as having 0% perceptual |
| # similarity. |
| if not 0 <= perceptual_similarity <= 1: |
| perceptual_similarity = 0 |
| self._perceptual_difference = 100 - (perceptual_similarity * 100) |
| |
| # Store the rgbdiff and whitediff images generated above. |
| diff_image_locator = _get_difference_locator( |
| expected_image_locator=expected_image_locator, |
| actual_image_locator=actual_image_locator) |
| basename = str(diff_image_locator) + image_suffix |
| _mkdir_unless_exists(os.path.join(storage_root, RGBDIFFS_SUBDIR)) |
| _mkdir_unless_exists(os.path.join(storage_root, WHITEDIFFS_SUBDIR)) |
| # TODO: Modify skpdiff's behavior so we can tell it exactly where to |
| # write the image files into, rather than having to move them around |
| # after skpdiff writes them out. |
| shutil.copyfile(rgb_diff_path, |
| os.path.join(storage_root, RGBDIFFS_SUBDIR, basename)) |
| shutil.copyfile(white_diff_path, |
| os.path.join(storage_root, WHITEDIFFS_SUBDIR, basename)) |
| |
| finally: |
| shutil.rmtree(skpdiff_output_dir) |
| |
| # TODO(epoger): Use properties instead of getters throughout. |
| # See http://stackoverflow.com/a/6618176 |
| def get_num_pixels_differing(self): |
| """Returns the absolute number of pixels that differ.""" |
| return self._num_pixels_differing |
| |
| def get_percent_pixels_differing(self): |
| """Returns the percentage of pixels that differ, as a float between |
| 0 and 100 (inclusive).""" |
| return ((float(self._num_pixels_differing) * 100) / |
| (self._width * self._height)) |
| |
| def get_perceptual_difference(self): |
| """Returns the perceptual difference percentage.""" |
| return self._perceptual_difference |
| |
| 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 { |
| KEY__DIFFERENCES__NUM_DIFF_PIXELS: self._num_pixels_differing, |
| KEY__DIFFERENCES__PERCENT_DIFF_PIXELS: |
| self.get_percent_pixels_differing(), |
| KEY__DIFFERENCES__MAX_DIFF_PER_CHANNEL: self._max_diff_per_channel, |
| KEY__DIFFERENCES__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: |
| storage_root: string; root path within the DB will store all of its stuff |
| """ |
| self._storage_root = storage_root |
| |
| # Dictionary of DiffRecords, keyed by (expected_image_locator, |
| # actual_image_locator) tuples. |
| self._diff_dict = {} |
| |
| @property |
| def storage_root(self): |
| return self._storage_root |
| |
| def add_image_pair(self, |
| expected_image_url, expected_image_locator, |
| actual_image_url, actual_image_locator): |
| """Download this pair of images (unless we already have them on local disk), |
| and prepare a DiffRecord for them. |
| |
| TODO(epoger): Make this asynchronously download images, rather than blocking |
| until the images have been downloaded and processed. |
| When we do that, we should probably add a new method that will block |
| until all of the images have been downloaded and processed. Otherwise, |
| we won't know when it's safe to start calling get_diff_record(). |
| jcgregorio notes: maybe just make ImageDiffDB thread-safe and create a |
| thread-pool/worker queue at a higher level that just uses ImageDiffDB? |
| |
| Args: |
| expected_image_url: file or HTTP url from which we will download the |
| expected image |
| expected_image_locator: a unique ID string under which we will store the |
| expected image within storage_root (probably including a checksum to |
| guarantee uniqueness) |
| actual_image_url: file or HTTP url from which we will download the |
| actual image |
| actual_image_locator: a unique ID string under which we will store the |
| actual image within storage_root (probably including a checksum to |
| guarantee uniqueness) |
| """ |
| expected_image_locator = _sanitize_locator(expected_image_locator) |
| actual_image_locator = _sanitize_locator(actual_image_locator) |
| key = (expected_image_locator, actual_image_locator) |
| if not key in self._diff_dict: |
| try: |
| new_diff_record = DiffRecord( |
| self._storage_root, |
| expected_image_url=expected_image_url, |
| expected_image_locator=expected_image_locator, |
| actual_image_url=actual_image_url, |
| actual_image_locator=actual_image_locator) |
| except Exception: |
| # If we can't create a real DiffRecord for this (expected, actual) pair, |
| # store None and the UI will show whatever information we DO have. |
| # Fixes http://skbug.com/2368 . |
| logging.exception( |
| 'got exception while creating a DiffRecord for ' |
| 'expected_image_url=%s , actual_image_url=%s; returning None' % ( |
| expected_image_url, actual_image_url)) |
| new_diff_record = None |
| self._diff_dict[key] = new_diff_record |
| |
| def get_diff_record(self, expected_image_locator, actual_image_locator): |
| """Returns the DiffRecord for this image pair. |
| |
| Raises a KeyError if we don't have a DiffRecord for this image pair. |
| """ |
| key = (_sanitize_locator(expected_image_locator), |
| _sanitize_locator(actual_image_locator)) |
| return self._diff_dict[key] |
| |
| |
| # Utility functions |
| |
| def _download_file(local_filepath, url): |
| """Download a file from url to local_filepath, unless it is already there. |
| |
| Args: |
| local_filepath: path on local disk where the image should be stored |
| url: URL from which we can download the image if we don't have it yet |
| """ |
| if not os.path.exists(local_filepath): |
| _mkdir_unless_exists(os.path.dirname(local_filepath)) |
| with contextlib.closing(urllib.urlopen(url)) as url_handle: |
| with open(local_filepath, 'wb') as file_handle: |
| shutil.copyfileobj(fsrc=url_handle, fdst=file_handle) |
| |
| |
| def _mkdir_unless_exists(path): |
| """Unless path refers to an already-existing directory, create it. |
| |
| Args: |
| path: path on local disk |
| """ |
| if not os.path.isdir(path): |
| os.makedirs(path) |
| |
| |
| def _sanitize_locator(locator): |
| """Returns a sanitized version of a locator (one in which we know none of the |
| characters will have special meaning in filenames). |
| |
| 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)) |