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#!/usr/bin/python
# -*- coding: utf-8 -*-
# ******************************************************************************
#
# Copyright (C) 2006 Olivier Tilloy <olivier@tilloy.net>
#
# This program is part of the pyexiv2 distribution.
#
# pyexiv2 is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# pyexiv2 is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with pyexiv2; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
#
#
# File: pyexiv2.py
# Author(s): Olivier Tilloy <olivier@tilloy.net>
# History: 28-Dec-06, Olivier Tilloy: created
# 30-Dec-06, Olivier Tilloy: documentation using doc strings
#
# ******************************************************************************
"""
Manipulation of EXIF and IPTC metadata embedded in image files.
This module provides a single class, Image, and utility functions to manipulate
EXIF and IPTC metadata embedded in image files such as JPEG and TIFF files.
EXIF and IPTC metadata can be accessed in both read and write modes.
This module is a higher-level interface to the Python binding of the excellent
C++ library Exiv2, libpyexiv2.
Its only class, Image, inherits from libpyexiv2.Image and provides convenient
methods for the manipulation of EXIF and IPTC metadata using Python's built-in
types and modules such as datetime.
These methods should be preferred to the ones directly provided by
libpyexiv2.Image.
A typical use of this binding is as follows:
import pyexiv2
import datetime
image = pyexiv2.Image('path/to/imagefile')
image.readMetadata()
print image.getAvailableExifTags()
print image.getExifTagValue('Exif.Photo.DateTimeOriginal')
today = datetime.datetime.today()
image.setExifTagValue('Exif.Photo.DateTimeOriginal', today)
image.writeMetadata()
...
"""
import libpyexiv2
import re
import datetime
def UndefinedToString(undefined):
"""
Convert an undefined string into its corresponding sequence of bytes.
Convert a string containing the ascii codes of a sequence of bytes, each
followed by a blank space, into the corresponding string (e.g.
"48 50 50 49 " will be converted into "0221").
The Undefined type is defined in the EXIF specification.
Keyword arguments:
undefined -- the string containing the ascii codes of a sequence of bytes
"""
return ''.join(map(lambda x: chr(int(x)), undefined.rstrip().split(' ')))
def StringToUndefined(sequence):
"""
Convert a string containing a sequence of bytes into its undefined form.
Convert a string containing a sequence of bytes into the corresponding
sequence of ascii codes, each followed by a blank space (e.g. "0221" will
be converted into "48 50 50 49 ").
The Undefined type is defined in the EXIF specification.
Keyword arguments:
sequence -- the string containing the sequence of bytes
"""
return ''.join(map(lambda x: '%d ' % ord(x), sequence))
class Image(libpyexiv2.Image):
"""
Provide convenient methods for the manipulation of EXIF and IPTC metadata.
Provide convenient methods for the manipulation of EXIF and IPTC metadata
embedded in image files such as JPEG and TIFF files, using Python's built-in
types and modules such as datetime.
Public methods:
getExifTagValue -- get the value associated to a key in EXIF metadata
setExifTagValue -- set the value associated to a key in EXIF metadata
"""
def getExifTagValue(self, key):
"""
Get the value associated to a key in EXIF metadata.
Get the value associated to a key in EXIF metadata.
Whenever possible, the value is typed using Python's built-in types or
modules such as datetime when the value is composed of a date and a time
(e.g. the EXIF tag 'Exif.Photo.DateTimeOriginal').
Keyword arguments:
key -- the EXIF key of the requested metadata tag
"""
tagType, tagValue = self.getExifTag(key)
if tagType == 'Byte':
return tagValue
elif tagType == 'Ascii':
# try to guess if the value is a datetime
pattern = re.compile("([0-9]{4}):([0-9]{2}):([0-9]{2}) ([0-9]{2}):([0-9]{2}):([0-9]{2})")
match = pattern.match(tagValue)
if match == None:
return tagValue.strip()
else:
v = map(int, match.groups())
return datetime.datetime(v[0], v[1], v[2], v[3], v[4], v[5])
elif tagType == 'Short':
return int(tagValue)
elif tagType == 'Long' or tagType == 'SLong':
return long(tagValue)
# for Rational and SRational types, we use tuples
# TODO: define a rational type?
elif tagType == 'Rational':
pattern = re.compile("([0-9]+)/([1-9][0-9]*)")
match = pattern.match(tagValue)
if match == None:
return long(0), long(1)
else:
v = map(long, match.groups())
return v[0], v[1]
elif tagType == 'SRational':
pattern = re.compile("(-?[0-9]+)/(-?[1-9][0-9]*)")
match = pattern.match(tagValue)
if match == None:
return long(0), long(1)
else:
v = map(long, match.groups())
return v[0], v[1]
elif tagType == 'Undefined':
# tagValue is a sequence of bytes whose codes are written as a
# string, each code being followed by a blank space (e.g.
# "48 50 50 49 " for "0221").
# Note: in the case of tag "Exif.Photo.UserComment", it is better to
# call method getExifTagToString() to obtain directly the value as a
# human-readable string.
return UndefinedToString(tagValue)
else:
# empty type and value
return
def setExifTagValue(self, key, value):
"""
Set the value associated to a key in EXIF metadata.
Set the value associated to a key in EXIF metadata.
The new value passed should be typed using Python's built-in types or
modules such as datetime when the value is composed of a date and a time
(e.g. the EXIF tag 'Exif.Photo.DateTimeOriginal'), the method takes care
of converting it before setting the internal EXIF tag value.
Keyword arguments:
key -- the EXIF key of the requested metadata tag
value -- the new value for the requested metadata tag
"""
valueType = value.__class__
if valueType == int or valueType == long:
strVal = str(value)
elif valueType == datetime.datetime:
strVal = value.strftime('%Y:%m:%d %H:%M:%S')
elif valueType == tuple:
strVal = '%s/%s' % (str(value[0]), str(value[1]))
else:
# Value must already be a string.
# Warning: no distinction is possible between values that really are
# strings (type 'Ascii') and those that are supposed to be sequences
# of bytes (type 'Undefined'), in which case value must be passed as
# a string correctly formatted, using utility function
# StringToUndefined().
strVal = value
self.setExifTag(key, strVal)
def _test():
print 'testing library pyexiv2...'
# TODO: various tests
print 'done.'
if __name__ == '__main__':
_test()
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