Python读取图片属性信息的实现方法

# -*- coding:utf-8 -*-
import binascii
 
class ParseMethod(object):
 @staticmethod
 def parse_default(f, count, offset):
 pass
 
 @staticmethod
 def parse_latitude(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 
 latitude = [0,0,0]
 for i in xrange(count):
 byte = f.read(4)
 numerator = byte.encode('hex')
 
 byte = f.read(4)
 denominator = byte.encode('hex')
 
 latitude[i] = float(int(numerator, 16)) / int(denominator, 16)
 
 
 print 'Latitude:	%.2f %.2f' %.2f"' % (latitude[0], latitude[1], latitude[2])
 f.seek(old_pos) 
 
 
 @staticmethod
 def parse_longtitude(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 
 longtitude = [0,0,0]
 for i in xrange(count):
 byte = f.read(4)
 numerator = byte.encode('hex')
 
 byte = f.read(4)
 denominator = byte.encode('hex')
 
 longtitude[i] = float(int(numerator, 16)) / int(denominator, 16)
 
 
 print 'Longtitude:	%.2f %.2f' %.2f"' % (longtitude[0], longtitude[1], longtitude[2])
 f.seek(old_pos) 
 
 @staticmethod
 def parse_make(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 byte = f.read(count)
 a = byte.encode('hex')
 print 'Make:	' + binascii.a2b_hex(a)
 f.seek(old_pos) 
 
 @staticmethod
 def parse_model(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 byte = f.read(count)
 a = byte.encode('hex')
 print 'Model:	' + binascii.a2b_hex(a)
 f.seek(old_pos) 
 
 @staticmethod
 def parse_datetime(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 byte = f.read(count)
 a = byte.encode('hex')
 print 'DateTime:	' + binascii.a2b_hex(a)
 f.seek(old_pos)
 
 # rational data type, 05
 @staticmethod
 def parse_xresolution(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 
 byte = f.read(4)
 numerator = byte.encode('hex')
 byte = f.read(4)
 denominator = byte.encode('hex')
 xre = int(numerator, 16) / int(denominator, 16)
 
 print 'XResolution:	' + str(xre) + ' dpi'
 f.seek(old_pos)
 
 @staticmethod
 def parse_yresolution(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 
 byte = f.read(4)
 numerator = byte.encode('hex')
 byte = f.read(4)
 denominator = byte.encode('hex')
 xre = int(numerator, 16) / int(denominator, 16)
 
 print 'YResolution:	' + str(xre) + ' dpi'
 f.seek(old_pos)
 
 @staticmethod
 def parse_exif_ifd(f, count, offset):
 old_pos = f.tell()
 f.seek(12 + offset)
 
 byte = f.read(2)
 a = byte.encode('hex') 
 exif_ifd_number = int(a, 16)
 
 for i in xrange(exif_ifd_number):
 byte = f.read(2)
 tag_id = byte.encode('hex')
 #print tag_id,
 
 byte = f.read(2)
 type_n = byte.encode('hex')
 #print type_n,
 
 byte = f.read(4)
 count = byte.encode('hex')
 #print count,
 
 byte = f.read(4)
 value_offset = byte.encode('hex')
 #print value_offset
 
 value_offset = int(value_offset, 16)
 EXIF_IFD_DICT.get(tag_id, ParseMethod.parse_default)(f, count, value_offset)
 
 f.seek(old_pos) 
 
 @staticmethod
 def parse_x_pixel(f, count, value):
 print 'X Pixels:	' + str(value)
 
 @staticmethod
 def parse_y_pixel(f, count, value):
 print 'y Pixels:	' + str(value)
 
 @staticmethod
 def parse_gps_ifd(f, count, offset):
 old_pos = f.tell() 
 f.seek(12 + offset)
 byte = f.read(2)
 a = byte.encode('hex') 
 gps_ifd_number = int(a, 16)
 
 for i in xrange(gps_ifd_number):
 byte = f.read(2)
 tag_id = byte.encode('hex')
 #print tag_id,
 
 byte = f.read(2)
 type_n = byte.encode('hex')
 #print type_n,
 
 byte = f.read(4)
 count = byte.encode('hex')
 #print count,
 
 byte = f.read(4)
 value_offset = byte.encode('hex')
 #print value_offset
 
 count = int(count, 16)
 value_offset = int(value_offset, 16)
 GPS_IFD_DICT.get(tag_id, ParseMethod.parse_default)(f, count, value_offset)
 
 f.seek(old_pos) 
 
IFD_dict = {
 '010f' : ParseMethod.parse_make ,
 '0110' : ParseMethod.parse_model ,
 '0132' : ParseMethod.parse_datetime ,
 '011a' : ParseMethod.parse_xresolution ,
 '011b' : ParseMethod.parse_yresolution ,
 '8769' : ParseMethod.parse_exif_ifd ,
 '8825' : ParseMethod.parse_gps_ifd
}
 
EXIF_IFD_DICT = {
 'a002' : ParseMethod.parse_x_pixel ,
 'a003' : ParseMethod.parse_y_pixel
}
 
GPS_IFD_DICT = {
 '0002' : ParseMethod.parse_latitude ,
 '0004' : ParseMethod.parse_longtitude
}
 
 
with open('image.jpg', 'rb') as f:
 byte = f.read(2)
 a = byte.encode('hex')
 print 'SOI Marker:	' + a
 
 byte = f.read(2)
 a = byte.encode('hex')
 print 'APP1 Marker:	' + a
 
 byte = f.read(2)
 a = byte.encode('hex')
 print 'APP1 Length:	' + str(int(a, 16)) + ' .Dec'
 
 byte = f.read(4)
 a = byte.encode('hex')
 print 'Identifier:	' + binascii.a2b_hex(a)
 
 byte = f.read(2)
 a = byte.encode('hex')
 print 'Pad:	' + a 
 
 print
 
 print 'Begin to print Header.... '
 print 'APP1 Body: '
 
 byte = f.read(2)
 a = byte.encode('hex')
 print 'Byte Order:	' + a 
 
 byte = f.read(2)
 a = byte.encode('hex')
 print '42:	' + a 
 
 byte = f.read(4)
 a = byte.encode('hex')
 print '0th IFD Offset:	' + a 
 
 print 'Finish print Header'
 
 print 'Begin to print 0th IFD....'
 print
 #print 'Total: ',
 byte = f.read(2)
 a = byte.encode('hex')
 interoperability_number = int(a, 16)
 #print interoperability_number
 
 
 for i in xrange(interoperability_number):
 byte = f.read(2)
 tag_id = byte.encode('hex')
 #print tag_id,
 
 byte = f.read(2)
 type_n = byte.encode('hex')
 #print type_n,
 
 byte = f.read(4)
 count = byte.encode('hex')
 #print count,
 
 byte = f.read(4)
 value_offset = byte.encode('hex')
 #print value_offset
 
 count = int(count, 16)
 value_offset = int(value_offset, 16)
 
 # simulate switch
 IFD_dict.get(tag_id, ParseMethod.parse_default)(f, count, value_offset)
 
 
 print
 print 'Finish print 0th IFD....'