xmp_jpeg.py

   1 # -*- coding: utf-8 -*-
   2 #######################################################################################
   3 #   Photo is a part of Plinn - http://plinn.org                                       #
   4 #   Copyright (C) 2008  Benoît PIN <benoit.pin@ensmp.fr>                              #
   5 #                                                                                     #
   6 #   This program is free software; you can redistribute it and/or                     #
   7 #   modify it under the terms of the GNU General Public License                       #
   8 #   as published by the Free Software Foundation; either version 2                    #
   9 #   of the License, or (at your option) any later version.                            #
  10 #                                                                                     #
  11 #   This program is distributed in the hope that it will be useful,                   #
  12 #   but WITHOUT ANY WARRANTY; without even the implied warranty of                    #
  13 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                     #
  14 #   GNU General Public License for more details.                                      #
  15 #                                                                                     #
  16 #   You should have received a copy of the GNU General Public License                 #
  17 #   along with this program; if not, write to the Free Software                       #
  18 #   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.   #
  19 #######################################################################################
  20 """ Jpeg plugin for xmp read/write support.
  21
  22
  23 """
  24
  25 from xmp import XMP
  26 from types import StringType
  27
  28 class JpegXmpIO(object):
  29
  30         JPEG_XMP_LEADIN = 'http://ns.adobe.com/xap/1.0/\x00'
  31         JPEG_XMP_LEADIN_LENGTH = len(JPEG_XMP_LEADIN)
  32
  33         MARKERS = {
  34                 0xFFC0: ("SOF0",        "Baseline DCT", True),
  35                 0xFFC1: ("SOF1",        "Extended Sequential DCT", True),
  36                 0xFFC2: ("SOF2",        "Progressive DCT", True),
  37                 0xFFC3: ("SOF3",        "Spatial lossless", True),
  38                 0xFFC4: ("DHT",         "Define Huffman table", True),
  39                 0xFFC5: ("SOF5",        "Differential sequential DCT", True),
  40                 0xFFC6: ("SOF6",        "Differential progressive DCT", True),
  41                 0xFFC7: ("SOF7",        "Differential spatial", True),
  42                 0xFFC8: ("JPG",         "Extension", False),
  43                 0xFFC9: ("SOF9",        "Extended sequential DCT (AC)", True),
  44                 0xFFCA: ("SOF10",       "Progressive DCT (AC)", True),
  45                 0xFFCB: ("SOF11",       "Spatial lossless DCT (AC)", True),
  46                 0xFFCC: ("DAC",         "Define arithmetic coding conditioning", True),
  47                 0xFFCD: ("SOF13",       "Differential sequential DCT (AC)", True),
  48                 0xFFCE: ("SOF14",       "Differential progressive DCT (AC)", True),
  49                 0xFFCF: ("SOF15",       "Differential spatial (AC)", True),
  50                 0xFFD0: ("RST0",        "Restart 0", False),
  51                 0xFFD1: ("RST1",        "Restart 1", False),
  52                 0xFFD2: ("RST2",        "Restart 2", False),
  53                 0xFFD3: ("RST3",        "Restart 3", False),
  54                 0xFFD4: ("RST4",        "Restart 4", False),
  55                 0xFFD5: ("RST5",        "Restart 5", False),
  56                 0xFFD6: ("RST6",        "Restart 6", False),
  57                 0xFFD7: ("RST7",        "Restart 7", False),
  58                 0xFFD8: ("SOI",         "Start of image", False),
  59                 0xFFD9: ("EOI",         "End of image", False),
  60                 0xFFDA: ("SOS",         "Start of scan", True),
  61                 0xFFDB: ("DQT",         "Define quantization table", True),
  62                 0xFFDC: ("DNL",         "Define number of lines", True),
  63                 0xFFDD: ("DRI",         "Define restart interval", True),
  64                 0xFFDE: ("DHP",         "Define hierarchical progression", True),
  65                 0xFFDF: ("EXP",         "Expand reference component", True),
  66                 0xFFE0: ("APP0",        "Application segment 0", True),
  67                 0xFFE1: ("APP1",        "Application segment 1", True),
  68                 0xFFE2: ("APP2",        "Application segment 2", True),
  69                 0xFFE3: ("APP3",        "Application segment 3", True),
  70                 0xFFE4: ("APP4",        "Application segment 4", True),
  71                 0xFFE5: ("APP5",        "Application segment 5", True),
  72                 0xFFE6: ("APP6",        "Application segment 6", True),
  73                 0xFFE7: ("APP7",        "Application segment 7", True),
  74                 0xFFE8: ("APP8",        "Application segment 8", True),
  75                 0xFFE9: ("APP9",        "Application segment 9", True),
  76                 0xFFEA: ("APP10",       "Application segment 10", True),
  77                 0xFFEB: ("APP11",       "Application segment 11", True),
  78                 0xFFEC: ("APP12",       "Application segment 12", True),
  79                 0xFFED: ("APP13",       "Application segment 13", True),
  80                 0xFFEE: ("APP14",       "Application segment 14", True),
  81                 0xFFEF: ("APP15",       "Application segment 15", True),
  82                 0xFFF0: ("JPG0",        "Extension 0", False),
  83                 0xFFF1: ("JPG1",        "Extension 1", False),
  84                 0xFFF2: ("JPG2",        "Extension 2", False),
  85                 0xFFF3: ("JPG3",        "Extension 3", False),
  86                 0xFFF4: ("JPG4",        "Extension 4", False),
  87                 0xFFF5: ("JPG5",        "Extension 5", False),
  88                 0xFFF6: ("JPG6",        "Extension 6", False),
  89                 0xFFF7: ("JPG7",        "Extension 7", False),
  90                 0xFFF8: ("JPG8",        "Extension 8", False),
  91                 0xFFF9: ("JPG9",        "Extension 9", False),
  92                 0xFFFA: ("JPG10",       "Extension 10", False),
  93                 0xFFFB: ("JPG11",       "Extension 11", False),
  94                 0xFFFC: ("JPG12",       "Extension 12", False),
  95                 0xFFFD: ("JPG13",       "Extension 13", False),
  96                 0xFFFE: ("COM",         "Comment", True)
  97         }
  98
  99
 100         @staticmethod
 101         def i16(c,o=0):
 102                 return ord(c[o+1]) + (ord(c[o])<<8)
 103
 104         @staticmethod
 105         def getBlockInfo(marker, f):
 106                 start = f.tell()
 107                 length = JpegXmpIO.i16(f.read(2))
 108
 109                 markerInfo = JpegXmpIO.MARKERS[marker]
 110                 blockInfo = { 'name' : markerInfo[0]
 111                                         , 'description' : markerInfo[1]
 112                                         , 'start' : start
 113                                         , 'length' : length}
 114
 115                 jump = start + length
 116                 f.seek(jump)
 117
 118                 return blockInfo
 119
 120         @staticmethod
 121         def getBlockInfos(f) :
 122                 f.seek(0)
 123                 s  = f.read(1)
 124
 125                 blockInfos = []
 126
 127                 while 1:
 128                         s = s + f.read(1)
 129                         i = JpegXmpIO.i16(s)
 130
 131                         if JpegXmpIO.MARKERS.has_key(i):
 132                                 name, desciption, handle = JpegXmpIO.MARKERS[i]
 133
 134                                 if handle:
 135                                         blockInfo = JpegXmpIO.getBlockInfo(i, f)
 136                                         blockInfos.append(blockInfo)
 137                                 if i == 0xFFDA: # start of scan
 138                                    break
 139                                 s = f.read(1)
 140                         elif i == 0 or i == 65535:
 141                                 # padded marker or junk; move on
 142                                 s = "\xff"
 143
 144                 return blockInfos
 145
 146
 147         @staticmethod
 148         def genJpegXmpBlock(uXmpData, paddingSize=2) :
 149                 block = u''
 150
 151                 block += JpegXmpIO.JPEG_XMP_LEADIN
 152                 block += XMP.genXMPPacket(uXmpData, paddingSize)
 153                 # utf-8 mandatory in jpeg files (xmp specification)
 154                 block = block.encode('utf-8')
 155
 156                 length = len(block) + 2
 157
 158                 # TODO : reduce padding size if this assertion occurs
 159                 assert length <= 0xfffd, "Jpeg block too long: %d (max: 0xfffd)" % hex(length)
 160
 161                 chrlength = chr(length >> 8 & 0xff) + chr(length & 0xff)
 162
 163                 block = chrlength + block
 164
 165                 return block
 166
 167
 168
 169         @staticmethod
 170         def read(f) :
 171
 172                 blockInfos = JpegXmpIO.getBlockInfos(f)
 173                 app1BlockInfos = [b for b in blockInfos if b['name'] == 'APP1']
 174
 175                 xmpBlocks = []
 176
 177                 for info in app1BlockInfos :
 178                         f.seek(info['start'])
 179                         data = f.read(info['length'])[2:]
 180                         if data.startswith(JpegXmpIO.JPEG_XMP_LEADIN) :
 181                                 xmpBlocks.append(data)
 182
 183                 assert len(xmpBlocks) <= 1, "Multiple xmp block data is not yet supported."
 184
 185                 if len(xmpBlocks) == 1 :
 186                         data = xmpBlocks[0]
 187                         packet = data[len(JpegXmpIO.JPEG_XMP_LEADIN):]
 188                         return packet
 189                 else :
 190                         return None
 191
 192         @staticmethod
 193         def write(original, new, uxmp) :
 194
 195                 blockInfos = JpegXmpIO.getBlockInfos(original)
 196                 app1BlockInfos = [b for b in blockInfos if b['name'] == 'APP1']
 197
 198                 xmpBlockInfos = []
 199
 200                 for info in app1BlockInfos :
 201                         original.seek(info['start'])
 202                         lead = original.read(JpegXmpIO.JPEG_XMP_LEADIN_LENGTH+2)[2:]
 203                         if lead == JpegXmpIO.JPEG_XMP_LEADIN :
 204                                 xmpBlockInfos.append(info)
 205
 206
 207                 assert len(xmpBlockInfos) <= 1, "Multiple xmp block data is not yet supported."
 208
 209                 if isinstance(uxmp, StringType) :
 210                         uxmp = unicode(uxmp, 'utf-8')
 211
 212                 if len(xmpBlockInfos) == 0 :
 213                         blockInfo = [b for b in blockInfos if b['name'] == 'APP13']
 214
 215                         if not blockInfo :
 216                                 blockInfo = [b for b in blockInfos if b['name'] == 'APP1']
 217
 218                         if not blockInfo :
 219                                 blockInfo = [b for b in blockInfos if b['name'] == 'APP0']
 220
 221                         if not blockInfo : raise ValueError, "No suitable place to write xmp segment"
 222
 223                         info = blockInfo[0]
 224                         print 'create xmp after: %s' % info['name']
 225
 226                         original.seek(0)
 227                         before = original.read(info['start'] + info['length'])
 228                         after = original.read()
 229
 230                         jpegBlock = '\xFF\xE1' + JpegXmpIO.genJpegXmpBlock(uxmp)
 231
 232                 else :
 233                         info = xmpBlockInfos[0]
 234
 235                         original.seek(0)
 236                         before = original.read(info['start'])
 237
 238                         original.seek(info['start'] + info['length'])
 239                         after = original.read()
 240
 241                         jpegBlock = JpegXmpIO.genJpegXmpBlock(uxmp)
 242
 243                 new.seek(0)
 244                 new.write(before)
 245                 new.write(jpegBlock)
 246                 new.write(after)
 247
 248                 # if original == new :
 249                 #       new.seek(0)
 250                 # else :
 251                 #       new.close()
 252                 #       original.close()
 253
 254
 255 XMP.registerReader('image/jpeg', JpegXmpIO.read)
 256 XMP.registerWriter('image/jpeg', JpegXmpIO.write)