mediagoblin/tests/test_exif.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import os
  18 import pkg_resources
  19 import Image
  20
  21 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  22     extract_exif, clean_exif, get_gps_data, get_useful
  23
  24
  25 def assert_in(a, b):
  26     assert a in b, "%r not in %r" % (a, b)
  27
  28
  29 GOOD_JPG = pkg_resources.resource_filename(
  30     'mediagoblin.tests',
  31     os.path.join(
  32         'test_exif',
  33         'good.jpg'))
  34 EMPTY_JPG = pkg_resources.resource_filename(
  35     'mediagoblin.tests',
  36     os.path.join(
  37         'test_exif',
  38         'empty.jpg'))
  39 BAD_JPG = pkg_resources.resource_filename(
  40     'mediagoblin.tests',
  41     os.path.join(
  42         'test_exif',
  43         'bad.jpg'))
  44 GPS_JPG = pkg_resources.resource_filename(
  45     'mediagoblin.tests',
  46     os.path.join(
  47         'test_exif',
  48         'has-gps.jpg'))
  49
  50
  51 def test_exif_extraction():
  52     '''
  53     Test EXIF extraction from a good image
  54     '''
  55     result = extract_exif(GOOD_JPG)
  56     clean = clean_exif(result)
  57     useful = get_useful(clean)
  58     gps = get_gps_data(result)
  59
  60     # Do we have the result?
  61     assert len(result) == 56
  62
  63     # Do we have clean data?
  64     assert len(clean) == 53
  65
  66     # GPS data?
  67     assert gps == {}
  68
  69     # Do we have the "useful" tags?
  70     assert useful == {
  71         'EXIF Flash': {
  72             'field_type': 3,
  73             'printable': u'Flash did not fire',
  74             'field_offset': 380,
  75             'tag': 37385,
  76             'values': [0],
  77             'field_length': 2},
  78         'EXIF ExposureTime': {
  79             'field_type': 5,
  80             'printable': '1/125',
  81             'field_offset': 700,
  82             'tag': 33434,
  83             'values': [[1, 125]],
  84             'field_length': 8},
  85         'EXIF FocalLength': {
  86             'field_type': 5,
  87             'printable': '18',
  88             'field_offset': 780,
  89             'tag': 37386,
  90             'values': [[18, 1]],
  91             'field_length': 8},
  92         'Image Model': {
  93             'field_type': 2,
  94             'printable': 'NIKON D80',
  95             'field_offset': 152,
  96             'tag': 272,
  97             'values': 'NIKON D80',
  98             'field_length': 10},
  99         'Image Make': {
 100             'field_type': 2,
 101             'printable': 'NIKON CORPORATION',
 102             'field_offset': 134,
 103             'tag': 271,
 104             'values': 'NIKON CORPORATION',
 105             'field_length': 18},
 106         'EXIF ExposureMode': {
 107             'field_type': 3,
 108             'printable': 'Manual Exposure',
 109             'field_offset': 584,
 110             'tag': 41986,
 111             'values': [1],
 112             'field_length': 2},
 113         'EXIF ISOSpeedRatings': {
 114             'field_type': 3,
 115             'printable': '100',
 116             'field_offset': 260,
 117             'tag': 34855,
 118             'values': [100],
 119             'field_length': 2},
 120         'EXIF FNumber': {
 121             'field_type': 5,
 122             'printable': '10',
 123             'field_offset': 708,
 124             'tag': 33437,
 125             'values': [[10, 1]],
 126             'field_length': 8}}
 127
 128
 129 def test_exif_image_orientation():
 130     '''
 131     Test image reorientation based on EXIF data
 132     '''
 133     result = extract_exif(GOOD_JPG)
 134
 135     image = exif_fix_image_orientation(
 136         Image.open(GOOD_JPG),
 137         result)
 138
 139     # Are the dimensions correct?
 140     assert image.size == (428, 640)
 141
 142     # If this pixel looks right, the rest of the image probably will too.
 143     assert_in(image.getdata()[10000],
 144               ((41, 28, 11), (43, 27, 11))
 145               )
 146
 147
 148 def test_exif_no_exif():
 149     '''
 150     Test an image without exif
 151     '''
 152     result = extract_exif(EMPTY_JPG)
 153     clean = clean_exif(result)
 154     useful = get_useful(clean)
 155     gps = get_gps_data(result)
 156
 157     assert result == {}
 158     assert clean == {}
 159     assert gps == {}
 160     assert useful == {}
 161
 162
 163 def test_exif_bad_image():
 164     '''
 165     Test EXIF extraction from a faithful, but bad image
 166     '''
 167     result = extract_exif(BAD_JPG)
 168     clean = clean_exif(result)
 169     useful = get_useful(clean)
 170     gps = get_gps_data(result)
 171
 172     assert result == {}
 173     assert clean == {}
 174     assert gps == {}
 175     assert useful == {}
 176
 177
 178 def test_exif_gps_data():
 179     '''
 180     Test extractiion of GPS data
 181     '''
 182     result = extract_exif(GPS_JPG)
 183     gps = get_gps_data(result)
 184
 185     assert gps == {
 186         'latitude': 59.336666666666666,
 187         'direction': 25.674046740467404,
 188         'altitude': 37.64365671641791,
 189         'longitude': 18.016166666666667}