ui/resources/resource_check/resource_scale_factors.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """Presubmit script for Chromium browser resources.
   6
   7 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
   8 for more details about the presubmit API built into depot_tools, and see
   9 http://www.chromium.org/developers/web-development-style-guide for the rules
  10 we're checking against here.
  11 """
  12
  13
  14 import os
  15 import struct
  16
  17
  18 class InvalidPNGException(Exception):
  19   pass
  20
  21
  22 class ResourceScaleFactors(object):
  23   """Verifier of image dimensions for Chromium resources.
  24
  25   This class verifies the image dimensions of resources in the various
  26   resource subdirectories.
  27
  28   Attributes:
  29       paths: An array of tuples giving the folders to check and their
  30           relevant scale factors. For example:
  31
  32           [(100, 'default_100_percent'), (200, 'default_200_percent')]
  33   """
  34
  35   def __init__(self, input_api, output_api, paths):
  36     """ Initializes ResourceScaleFactors with paths."""
  37     self.input_api = input_api
  38     self.output_api = output_api
  39     self.paths = paths
  40
  41   def RunChecks(self):
  42     """Verifies the scale factors of resources being added or modified.
  43
  44     Returns:
  45         An array of presubmit errors if any images were detected not
  46         having the correct dimensions.
  47     """
  48     def ImageSize(filename):
  49       with open(filename, 'rb', buffering=0) as f:
  50         data = f.read(24)
  51       if data[:8] != '\x89PNG\r\n\x1A\n' or data[12:16] != 'IHDR':
  52         raise InvalidPNGException
  53       return struct.unpack('>ii', data[16:24])
  54
  55     # Returns a list of valid scaled image sizes. The valid sizes are the
  56     # floor and ceiling of (base_size * scale_percent / 100). This is equivalent
  57     # to requiring that the actual scaled size is less than one pixel away from
  58     # the exact scaled size.
  59     def ValidSizes(base_size, scale_percent):
  60       return sorted(set([(base_size * scale_percent) / 100,
  61                          (base_size * scale_percent + 99) / 100]))
  62
  63     repository_path = self.input_api.os_path.relpath(
  64         self.input_api.PresubmitLocalPath(),
  65         self.input_api.change.RepositoryRoot())
  66     results = []
  67
  68     # Check for affected files in any of the paths specified.
  69     affected_files = self.input_api.AffectedFiles(include_deletes=False)
  70     files = []
  71     for f in affected_files:
  72       for path_spec in self.paths:
  73         path_root = self.input_api.os_path.join(
  74             repository_path, path_spec[1])
  75         if (f.LocalPath().endswith('.png') and
  76             f.LocalPath().startswith(path_root)):
  77           # Only save the relative path from the resource directory.
  78           relative_path = self.input_api.os_path.relpath(f.LocalPath(),
  79               path_root)
  80           if relative_path not in files:
  81             files.append(relative_path)
  82
  83     corrupt_png_error = ('Corrupt PNG in file %s. Note that binaries are not '
  84         'correctly uploaded to the code review tool and must be directly '
  85         'submitted using the dcommit command.')
  86     for f in files:
  87       base_image = self.input_api.os_path.join(self.paths[0][1], f)
  88       if not os.path.exists(base_image):
  89         results.append(self.output_api.PresubmitError(
  90             'Base image %s does not exist' % self.input_api.os_path.join(
  91             repository_path, base_image)))
  92         continue
  93       try:
  94         base_dimensions = ImageSize(base_image)
  95       except InvalidPNGException:
  96         results.append(self.output_api.PresubmitError(corrupt_png_error %
  97             self.input_api.os_path.join(repository_path, base_image)))
  98         continue
  99       # Find all scaled versions of the base image and verify their sizes.
 100       for i in range(1, len(self.paths)):
 101         image_path = self.input_api.os_path.join(self.paths[i][1], f)
 102         if not os.path.exists(image_path):
 103           continue
 104         # Ensure that each image for a particular scale factor is the
 105         # correct scale of the base image.
 106         try:
 107           scaled_dimensions = ImageSize(image_path)
 108         except InvalidPNGException:
 109           results.append(self.output_api.PresubmitError(corrupt_png_error %
 110               self.input_api.os_path.join(repository_path, image_path)))
 111           continue
 112         for dimension_name, base_size, scaled_size in zip(
 113             ('width', 'height'), base_dimensions, scaled_dimensions):
 114           valid_sizes = ValidSizes(base_size, self.paths[i][0])
 115           if scaled_size not in valid_sizes:
 116             results.append(self.output_api.PresubmitError(
 117                 'Image %s has %s %d, expected to be %s' % (
 118                 self.input_api.os_path.join(repository_path, image_path),
 119                 dimension_name,
 120                 scaled_size,
 121                 ' or '.join(map(str, valid_sizes)))))
 122     return results