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 try:
  19     from PIL import Image
  20 except ImportError:
  21     import Image
  22
  23 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  24     extract_exif, clean_exif, get_gps_data, get_useful
  25 from .resources import GOOD_JPG, EMPTY_JPG, BAD_JPG, GPS_JPG
  26
  27
  28 def assert_in(a, b):
  29     assert a in b, "%r not in %r" % (a, b)
  30
  31
  32 def test_exif_extraction():
  33     '''
  34     Test EXIF extraction from a good image
  35     '''
  36     result = extract_exif(GOOD_JPG)
  37     clean = clean_exif(result)
  38     useful = get_useful(clean)
  39     gps = get_gps_data(result)
  40
  41     # Do we have the result?
  42     assert len(result) == 56
  43
  44     # Do we have clean data?
  45     assert len(clean) == 53
  46
  47     # GPS data?
  48     assert gps == {}
  49
  50     # Do we have the "useful" tags?
  51     assert useful == {
  52         'EXIF Flash': {
  53             'field_type': 3,
  54             'printable': u'Flash did not fire',
  55             'field_offset': 380,
  56             'tag': 37385,
  57             'values': [0],
  58             'field_length': 2},
  59         'EXIF ExposureTime': {
  60             'field_type': 5,
  61             'printable': '1/125',
  62             'field_offset': 700,
  63             'tag': 33434,
  64             'values': [[1, 125]],
  65             'field_length': 8},
  66         'EXIF FocalLength': {
  67             'field_type': 5,
  68             'printable': '18',
  69             'field_offset': 780,
  70             'tag': 37386,
  71             'values': [[18, 1]],
  72             'field_length': 8},
  73         'Image Model': {
  74             'field_type': 2,
  75             'printable': 'NIKON D80',
  76             'field_offset': 152,
  77             'tag': 272,
  78             'values': 'NIKON D80',
  79             'field_length': 10},
  80         'Image Make': {
  81             'field_type': 2,
  82             'printable': 'NIKON CORPORATION',
  83             'field_offset': 134,
  84             'tag': 271,
  85             'values': 'NIKON CORPORATION',
  86             'field_length': 18},
  87         'EXIF ExposureMode': {
  88             'field_type': 3,
  89             'printable': 'Manual Exposure',
  90             'field_offset': 584,
  91             'tag': 41986,
  92             'values': [1],
  93             'field_length': 2},
  94         'EXIF ISOSpeedRatings': {
  95             'field_type': 3,
  96             'printable': '100',
  97             'field_offset': 260,
  98             'tag': 34855,
  99             'values': [100],
 100             'field_length': 2},
 101         'EXIF FNumber': {
 102             'field_type': 5,
 103             'printable': '10',
 104             'field_offset': 708,
 105             'tag': 33437,
 106             'values': [[10, 1]],
 107             'field_length': 8}}
 108
 109
 110 def test_exif_image_orientation():
 111     '''
 112     Test image reorientation based on EXIF data
 113     '''
 114     result = extract_exif(GOOD_JPG)
 115
 116     image = exif_fix_image_orientation(
 117         Image.open(GOOD_JPG),
 118         result)
 119
 120     # Are the dimensions correct?
 121     assert image.size == (428, 640)
 122
 123     # If this pixel looks right, the rest of the image probably will too.
 124     assert_in(image.getdata()[10000],
 125               ((41, 28, 11), (43, 27, 11))
 126               )
 127
 128
 129 def test_exif_no_exif():
 130     '''
 131     Test an image without exif
 132     '''
 133     result = extract_exif(EMPTY_JPG)
 134     clean = clean_exif(result)
 135     useful = get_useful(clean)
 136     gps = get_gps_data(result)
 137
 138     assert result == {}
 139     assert clean == {}
 140     assert gps == {}
 141     assert useful == {}
 142
 143
 144 def test_exif_bad_image():
 145     '''
 146     Test EXIF extraction from a faithful, but bad image
 147     '''
 148     result = extract_exif(BAD_JPG)
 149     clean = clean_exif(result)
 150     useful = get_useful(clean)
 151     gps = get_gps_data(result)
 152
 153     assert result == {}
 154     assert clean == {}
 155     assert gps == {}
 156     assert useful == {}
 157
 158
 159 def test_exif_gps_data():
 160     '''
 161     Test extractiion of GPS data
 162     '''
 163     result = extract_exif(GPS_JPG)
 164     gps = get_gps_data(result)
 165
 166     assert gps == {
 167         'latitude': 59.336666666666666,
 168         'direction': 25.674046740467404,
 169         'altitude': 37.64365671641791,
 170         'longitude': 18.016166666666667}