mediagoblin/media_types/image/processing.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011 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 Image
  18 import os
  19
  20 from mediagoblin import mg_globals as mgg
  21 from mediagoblin.processing import BadMediaFail, \
  22     create_pub_filepath, THUMB_SIZE, MEDIUM_SIZE
  23 from mediagoblin.media_types.image.EXIF import process_file
  24 from mediagoblin.tools.translate import pass_to_ugettext as _
  25
  26 def process_image(entry):
  27     """
  28     Code to process an image
  29     """
  30     workbench = mgg.workbench_manager.create_workbench()
  31     # Conversions subdirectory to avoid collisions
  32     conversions_subdir = os.path.join(
  33         workbench.dir, 'conversions')
  34     os.mkdir(conversions_subdir)
  35
  36     queued_filepath = entry.queued_media_file
  37     queued_filename = workbench.localized_file(
  38         mgg.queue_store, queued_filepath,
  39         'source')
  40
  41     filename_bits = os.path.splitext(queued_filename)
  42     basename = os.path.split(filename_bits[0])[1]
  43     extension = filename_bits[1].lower()
  44
  45     # EXIF extraction
  46     exif_tags = extract_exif(queued_filename)
  47     gps_data = get_gps_data(exif_tags)
  48
  49     try:
  50         thumb = Image.open(queued_filename)
  51     except IOError:
  52         raise BadMediaFail()
  53
  54     thumb = exif_fix_image_orientation(thumb, exif_tags)
  55
  56     thumb.thumbnail(THUMB_SIZE, Image.ANTIALIAS)
  57
  58     # Copy the thumb to the conversion subdir, then remotely.
  59     thumb_filename = 'thumbnail' + extension
  60     thumb_filepath = create_pub_filepath(entry, thumb_filename)
  61     tmp_thumb_filename = os.path.join(
  62         conversions_subdir, thumb_filename)
  63     with file(tmp_thumb_filename, 'w') as thumb_file:
  64         thumb.save(thumb_file)
  65     mgg.public_store.copy_local_to_storage(
  66         tmp_thumb_filename, thumb_filepath)
  67
  68     # If the size of the original file exceeds the specified size of a `medium`
  69     # file, a `medium.jpg` files is created and later associated with the media
  70     # entry.
  71     medium = Image.open(queued_filename)
  72     # Fox orientation
  73     medium = exif_fix_image_orientation(medium, exif_tags)
  74
  75     if medium.size[0] > MEDIUM_SIZE[0] or medium.size[1] > MEDIUM_SIZE[1]:
  76         medium.thumbnail(MEDIUM_SIZE, Image.ANTIALIAS)
  77
  78     medium_filename = 'medium' + extension
  79     medium_filepath = create_pub_filepath(entry, medium_filename)
  80     tmp_medium_filename = os.path.join(
  81         conversions_subdir, medium_filename)
  82
  83     with file(tmp_medium_filename, 'w') as medium_file:
  84         medium.save(medium_file)
  85
  86     mgg.public_store.copy_local_to_storage(
  87         tmp_medium_filename, medium_filepath)
  88
  89     # we have to re-read because unlike PIL, not everything reads
  90     # things in string representation :)
  91     queued_file = file(queued_filename, 'rb')
  92
  93     with queued_file:
  94         #create_pub_filepath(entry, queued_filepath[-1])
  95         original_filepath = create_pub_filepath(entry, basename + extension)
  96
  97         with mgg.public_store.get_file(original_filepath, 'wb') \
  98             as original_file:
  99             original_file.write(queued_file.read())
 100
 101     # Remove queued media file from storage and database
 102     mgg.queue_store.delete_file(queued_filepath)
 103     entry.queued_media_file = []
 104
 105     # Insert media file information into database
 106     media_files_dict = entry.setdefault('media_files', {})
 107     media_files_dict['thumb'] = thumb_filepath
 108     media_files_dict['original'] = original_filepath
 109     media_files_dict['medium'] = medium_filepath
 110
 111     # Insert exif data into database
 112     media_data = entry.setdefault('media_data', {})
 113     media_data['exif'] = clean_exif(exif_tags)
 114     media_data['gps'] = gps_data
 115
 116     # clean up workbench
 117     workbench.destroy_self()
 118
 119 def exif_fix_image_orientation(im, exif_tags):
 120     """
 121     Translate any EXIF orientation to raw orientation
 122
 123     Cons:
 124     - REDUCES IMAGE QUALITY by recompressig it
 125
 126     Pros:
 127     - Cures my neck pain
 128     """
 129     # Rotate image
 130     if 'Image Orientation' in exif_tags:
 131         rotation_map = {
 132             3: 180,
 133             6: 270,
 134             8: 90}
 135         orientation = exif_tags['Image Orientation'].values[0]
 136         if orientation in rotation_map.keys():
 137             im = im.rotate(
 138                 rotation_map[orientation])
 139
 140     return im
 141
 142 def extract_exif(filename):
 143     """
 144     Returns EXIF tags found in file at ``filename``
 145     """
 146     exif_tags = {}
 147
 148     try:
 149         image = open(filename)
 150         exif_tags = process_file(image)
 151     except IOError:
 152         BadMediaFail(_('Could not read the image file.'))
 153
 154     return exif_tags
 155
 156 def clean_exif(exif):
 157     # Clean the result from anything the database cannot handle
 158
 159     # Discard any JPEG thumbnail, for database compatibility
 160     # and that I cannot see a case when we would use it.
 161     # It takes up some space too.
 162     disabled_tags = [
 163         'Thumbnail JPEGInterchangeFormatLength',
 164         'JPEGThumbnail',
 165         'Thumbnail JPEGInterchangeFormat']
 166
 167     clean_exif = {}
 168
 169     for key, value in exif.items():
 170         if not key in disabled_tags:
 171             clean_exif[key] = str(value)
 172
 173     return clean_exif
 174
 175
 176 def get_gps_data(exif):
 177     """
 178     Processes EXIF data returned by EXIF.py
 179     """
 180     if not 'Image GPSInfo' in exif:
 181         return False
 182
 183     gps_data = {}
 184
 185     try:
 186         dms_data = {
 187             'latitude': exif['GPS GPSLatitude'],
 188             'longitude': exif['GPS GPSLongitude']}
 189
 190         for key, dat in dms_data.items():
 191             gps_data[key] = (
 192                 lambda v:
 193                     float(v[0].num) / float(v[0].den) \
 194                     + (float(v[1].num) / float(v[1].den) / 60 )\
 195                     + (float(v[2].num) / float(v[2].den) / (60 * 60))
 196                 )(dat.values)
 197     except KeyError:
 198         pass
 199
 200     try:
 201         gps_data['direction'] = (
 202             lambda d:
 203                 float(d.num) / float(d.den)
 204             )(exif['GPS GPSImgDirection'].values[0])
 205     except KeyError:
 206         pass
 207
 208     try:
 209         gps_data['altitude'] = (
 210             lambda a:
 211                 float(a.num) / float(a.den)
 212             )(exif['GPS GPSAltitude'].values[0])
 213     except KeyError:
 214         pass
 215
 216     return gps_data
 217
 218
 219 if __name__ == '__main__':
 220     import sys
 221     import pprint
 222
 223     pp = pprint.PrettyPrinter()
 224
 225     result = extract_exif(sys.argv[1])
 226     gps = get_gps_data(result)
 227
 228     import pdb
 229     pdb.set_trace()
 230
 231     print pp.pprint(
 232         result)