492 lines
16 KiB
Python
492 lines
16 KiB
Python
#
|
|
# The Python Imaging Library.
|
|
# $Id$
|
|
#
|
|
# JPEG (JFIF) file handling
|
|
#
|
|
# See "Digital Compression and Coding of Continous-Tone Still Images,
|
|
# Part 1, Requirements and Guidelines" (CCITT T.81 / ISO 10918-1)
|
|
#
|
|
# History:
|
|
# 1995-09-09 fl Created
|
|
# 1995-09-13 fl Added full parser
|
|
# 1996-03-25 fl Added hack to use the IJG command line utilities
|
|
# 1996-05-05 fl Workaround Photoshop 2.5 CMYK polarity bug
|
|
# 1996-05-28 fl Added draft support, JFIF version (0.1)
|
|
# 1996-12-30 fl Added encoder options, added progression property (0.2)
|
|
# 1997-08-27 fl Save mode 1 images as BW (0.3)
|
|
# 1998-07-12 fl Added YCbCr to draft and save methods (0.4)
|
|
# 1998-10-19 fl Don't hang on files using 16-bit DQT's (0.4.1)
|
|
# 2001-04-16 fl Extract DPI settings from JFIF files (0.4.2)
|
|
# 2002-07-01 fl Skip pad bytes before markers; identify Exif files (0.4.3)
|
|
# 2003-04-25 fl Added experimental EXIF decoder (0.5)
|
|
# 2003-06-06 fl Added experimental EXIF GPSinfo decoder
|
|
# 2003-09-13 fl Extract COM markers
|
|
# 2009-09-06 fl Added icc_profile support (from Florian Hoech)
|
|
# 2009-03-06 fl Changed CMYK handling; always use Adobe polarity (0.6)
|
|
# 2009-03-08 fl Added subsampling support (from Justin Huff).
|
|
#
|
|
# Copyright (c) 1997-2003 by Secret Labs AB.
|
|
# Copyright (c) 1995-1996 by Fredrik Lundh.
|
|
#
|
|
# See the README file for information on usage and redistribution.
|
|
#
|
|
|
|
__version__ = "0.6"
|
|
|
|
import array, struct
|
|
import string
|
|
import Image, ImageFile
|
|
|
|
def i16(c,o=0):
|
|
return ord(c[o+1]) + (ord(c[o])<<8)
|
|
|
|
def i32(c,o=0):
|
|
return ord(c[o+3]) + (ord(c[o+2])<<8) + (ord(c[o+1])<<16) + (ord(c[o])<<24)
|
|
|
|
#
|
|
# Parser
|
|
|
|
def Skip(self, marker):
|
|
n = i16(self.fp.read(2))-2
|
|
ImageFile._safe_read(self.fp, n)
|
|
|
|
def APP(self, marker):
|
|
#
|
|
# Application marker. Store these in the APP dictionary.
|
|
# Also look for well-known application markers.
|
|
|
|
n = i16(self.fp.read(2))-2
|
|
s = ImageFile._safe_read(self.fp, n)
|
|
|
|
app = "APP%d" % (marker&15)
|
|
|
|
self.app[app] = s # compatibility
|
|
self.applist.append((app, s))
|
|
|
|
if marker == 0xFFE0 and s[:4] == "JFIF":
|
|
# extract JFIF information
|
|
self.info["jfif"] = version = i16(s, 5) # version
|
|
self.info["jfif_version"] = divmod(version, 256)
|
|
# extract JFIF properties
|
|
try:
|
|
jfif_unit = ord(s[7])
|
|
jfif_density = i16(s, 8), i16(s, 10)
|
|
except:
|
|
pass
|
|
else:
|
|
if jfif_unit == 1:
|
|
self.info["dpi"] = jfif_density
|
|
self.info["jfif_unit"] = jfif_unit
|
|
self.info["jfif_density"] = jfif_density
|
|
elif marker == 0xFFE1 and s[:5] == "Exif\0":
|
|
# extract Exif information (incomplete)
|
|
self.info["exif"] = s # FIXME: value will change
|
|
elif marker == 0xFFE2 and s[:5] == "FPXR\0":
|
|
# extract FlashPix information (incomplete)
|
|
self.info["flashpix"] = s # FIXME: value will change
|
|
elif marker == 0xFFE2 and s[:12] == "ICC_PROFILE\0":
|
|
# Since an ICC profile can be larger than the maximum size of
|
|
# a JPEG marker (64K), we need provisions to split it into
|
|
# multiple markers. The format defined by the ICC specifies
|
|
# one or more APP2 markers containing the following data:
|
|
# Identifying string ASCII "ICC_PROFILE\0" (12 bytes)
|
|
# Marker sequence number 1, 2, etc (1 byte)
|
|
# Number of markers Total of APP2's used (1 byte)
|
|
# Profile data (remainder of APP2 data)
|
|
# Decoders should use the marker sequence numbers to
|
|
# reassemble the profile, rather than assuming that the APP2
|
|
# markers appear in the correct sequence.
|
|
self.icclist.append(s)
|
|
elif marker == 0xFFEE and s[:5] == "Adobe":
|
|
self.info["adobe"] = i16(s, 5)
|
|
# extract Adobe custom properties
|
|
try:
|
|
adobe_transform = ord(s[1])
|
|
except:
|
|
pass
|
|
else:
|
|
self.info["adobe_transform"] = adobe_transform
|
|
|
|
def COM(self, marker):
|
|
#
|
|
# Comment marker. Store these in the APP dictionary.
|
|
|
|
n = i16(self.fp.read(2))-2
|
|
s = ImageFile._safe_read(self.fp, n)
|
|
|
|
self.app["COM"] = s # compatibility
|
|
self.applist.append(("COM", s))
|
|
|
|
def SOF(self, marker):
|
|
#
|
|
# Start of frame marker. Defines the size and mode of the
|
|
# image. JPEG is colour blind, so we use some simple
|
|
# heuristics to map the number of layers to an appropriate
|
|
# mode. Note that this could be made a bit brighter, by
|
|
# looking for JFIF and Adobe APP markers.
|
|
|
|
n = i16(self.fp.read(2))-2
|
|
s = ImageFile._safe_read(self.fp, n)
|
|
self.size = i16(s[3:]), i16(s[1:])
|
|
|
|
self.bits = ord(s[0])
|
|
if self.bits != 8:
|
|
raise SyntaxError("cannot handle %d-bit layers" % self.bits)
|
|
|
|
self.layers = ord(s[5])
|
|
if self.layers == 1:
|
|
self.mode = "L"
|
|
elif self.layers == 3:
|
|
self.mode = "RGB"
|
|
elif self.layers == 4:
|
|
self.mode = "CMYK"
|
|
else:
|
|
raise SyntaxError("cannot handle %d-layer images" % self.layers)
|
|
|
|
if marker in [0xFFC2, 0xFFC6, 0xFFCA, 0xFFCE]:
|
|
self.info["progressive"] = self.info["progression"] = 1
|
|
|
|
if self.icclist:
|
|
# fixup icc profile
|
|
self.icclist.sort() # sort by sequence number
|
|
if ord(self.icclist[0][13]) == len(self.icclist):
|
|
profile = []
|
|
for p in self.icclist:
|
|
profile.append(p[14:])
|
|
icc_profile = string.join(profile, "")
|
|
else:
|
|
icc_profile = None # wrong number of fragments
|
|
self.info["icc_profile"] = icc_profile
|
|
self.icclist = None
|
|
|
|
for i in range(6, len(s), 3):
|
|
t = s[i:i+3]
|
|
# 4-tuples: id, vsamp, hsamp, qtable
|
|
self.layer.append((t[0], ord(t[1])/16, ord(t[1])&15, ord(t[2])))
|
|
|
|
def DQT(self, marker):
|
|
#
|
|
# Define quantization table. Support baseline 8-bit tables
|
|
# only. Note that there might be more than one table in
|
|
# each marker.
|
|
|
|
# FIXME: The quantization tables can be used to estimate the
|
|
# compression quality.
|
|
|
|
n = i16(self.fp.read(2))-2
|
|
s = ImageFile._safe_read(self.fp, n)
|
|
while len(s):
|
|
if len(s) < 65:
|
|
raise SyntaxError("bad quantization table marker")
|
|
v = ord(s[0])
|
|
if v/16 == 0:
|
|
self.quantization[v&15] = array.array("b", s[1:65])
|
|
s = s[65:]
|
|
else:
|
|
return # FIXME: add code to read 16-bit tables!
|
|
# raise SyntaxError, "bad quantization table element size"
|
|
|
|
|
|
#
|
|
# JPEG marker table
|
|
|
|
MARKER = {
|
|
0xFFC0: ("SOF0", "Baseline DCT", SOF),
|
|
0xFFC1: ("SOF1", "Extended Sequential DCT", SOF),
|
|
0xFFC2: ("SOF2", "Progressive DCT", SOF),
|
|
0xFFC3: ("SOF3", "Spatial lossless", SOF),
|
|
0xFFC4: ("DHT", "Define Huffman table", Skip),
|
|
0xFFC5: ("SOF5", "Differential sequential DCT", SOF),
|
|
0xFFC6: ("SOF6", "Differential progressive DCT", SOF),
|
|
0xFFC7: ("SOF7", "Differential spatial", SOF),
|
|
0xFFC8: ("JPG", "Extension", None),
|
|
0xFFC9: ("SOF9", "Extended sequential DCT (AC)", SOF),
|
|
0xFFCA: ("SOF10", "Progressive DCT (AC)", SOF),
|
|
0xFFCB: ("SOF11", "Spatial lossless DCT (AC)", SOF),
|
|
0xFFCC: ("DAC", "Define arithmetic coding conditioning", Skip),
|
|
0xFFCD: ("SOF13", "Differential sequential DCT (AC)", SOF),
|
|
0xFFCE: ("SOF14", "Differential progressive DCT (AC)", SOF),
|
|
0xFFCF: ("SOF15", "Differential spatial (AC)", SOF),
|
|
0xFFD0: ("RST0", "Restart 0", None),
|
|
0xFFD1: ("RST1", "Restart 1", None),
|
|
0xFFD2: ("RST2", "Restart 2", None),
|
|
0xFFD3: ("RST3", "Restart 3", None),
|
|
0xFFD4: ("RST4", "Restart 4", None),
|
|
0xFFD5: ("RST5", "Restart 5", None),
|
|
0xFFD6: ("RST6", "Restart 6", None),
|
|
0xFFD7: ("RST7", "Restart 7", None),
|
|
0xFFD8: ("SOI", "Start of image", None),
|
|
0xFFD9: ("EOI", "End of image", None),
|
|
0xFFDA: ("SOS", "Start of scan", Skip),
|
|
0xFFDB: ("DQT", "Define quantization table", DQT),
|
|
0xFFDC: ("DNL", "Define number of lines", Skip),
|
|
0xFFDD: ("DRI", "Define restart interval", Skip),
|
|
0xFFDE: ("DHP", "Define hierarchical progression", SOF),
|
|
0xFFDF: ("EXP", "Expand reference component", Skip),
|
|
0xFFE0: ("APP0", "Application segment 0", APP),
|
|
0xFFE1: ("APP1", "Application segment 1", APP),
|
|
0xFFE2: ("APP2", "Application segment 2", APP),
|
|
0xFFE3: ("APP3", "Application segment 3", APP),
|
|
0xFFE4: ("APP4", "Application segment 4", APP),
|
|
0xFFE5: ("APP5", "Application segment 5", APP),
|
|
0xFFE6: ("APP6", "Application segment 6", APP),
|
|
0xFFE7: ("APP7", "Application segment 7", APP),
|
|
0xFFE8: ("APP8", "Application segment 8", APP),
|
|
0xFFE9: ("APP9", "Application segment 9", APP),
|
|
0xFFEA: ("APP10", "Application segment 10", APP),
|
|
0xFFEB: ("APP11", "Application segment 11", APP),
|
|
0xFFEC: ("APP12", "Application segment 12", APP),
|
|
0xFFED: ("APP13", "Application segment 13", APP),
|
|
0xFFEE: ("APP14", "Application segment 14", APP),
|
|
0xFFEF: ("APP15", "Application segment 15", APP),
|
|
0xFFF0: ("JPG0", "Extension 0", None),
|
|
0xFFF1: ("JPG1", "Extension 1", None),
|
|
0xFFF2: ("JPG2", "Extension 2", None),
|
|
0xFFF3: ("JPG3", "Extension 3", None),
|
|
0xFFF4: ("JPG4", "Extension 4", None),
|
|
0xFFF5: ("JPG5", "Extension 5", None),
|
|
0xFFF6: ("JPG6", "Extension 6", None),
|
|
0xFFF7: ("JPG7", "Extension 7", None),
|
|
0xFFF8: ("JPG8", "Extension 8", None),
|
|
0xFFF9: ("JPG9", "Extension 9", None),
|
|
0xFFFA: ("JPG10", "Extension 10", None),
|
|
0xFFFB: ("JPG11", "Extension 11", None),
|
|
0xFFFC: ("JPG12", "Extension 12", None),
|
|
0xFFFD: ("JPG13", "Extension 13", None),
|
|
0xFFFE: ("COM", "Comment", COM)
|
|
}
|
|
|
|
|
|
def _accept(prefix):
|
|
return prefix[0] == "\377"
|
|
|
|
##
|
|
# Image plugin for JPEG and JFIF images.
|
|
|
|
class JpegImageFile(ImageFile.ImageFile):
|
|
|
|
format = "JPEG"
|
|
format_description = "JPEG (ISO 10918)"
|
|
|
|
def _open(self):
|
|
|
|
s = self.fp.read(1)
|
|
|
|
if ord(s[0]) != 255:
|
|
raise SyntaxError("not a JPEG file")
|
|
|
|
# Create attributes
|
|
self.bits = self.layers = 0
|
|
|
|
# JPEG specifics (internal)
|
|
self.layer = []
|
|
self.huffman_dc = {}
|
|
self.huffman_ac = {}
|
|
self.quantization = {}
|
|
self.app = {} # compatibility
|
|
self.applist = []
|
|
self.icclist = []
|
|
|
|
while 1:
|
|
|
|
s = s + self.fp.read(1)
|
|
|
|
i = i16(s)
|
|
|
|
if MARKER.has_key(i):
|
|
name, description, handler = MARKER[i]
|
|
# print hex(i), name, description
|
|
if handler is not None:
|
|
handler(self, i)
|
|
if i == 0xFFDA: # start of scan
|
|
rawmode = self.mode
|
|
if self.mode == "CMYK":
|
|
rawmode = "CMYK;I" # assume adobe conventions
|
|
self.tile = [("jpeg", (0,0) + self.size, 0, (rawmode, ""))]
|
|
# self.__offset = self.fp.tell()
|
|
break
|
|
s = self.fp.read(1)
|
|
elif i == 0 or i == 65535:
|
|
# padded marker or junk; move on
|
|
s = "\xff"
|
|
else:
|
|
raise SyntaxError("no marker found")
|
|
|
|
def draft(self, mode, size):
|
|
|
|
if len(self.tile) != 1:
|
|
return
|
|
|
|
d, e, o, a = self.tile[0]
|
|
scale = 0
|
|
|
|
if a[0] == "RGB" and mode in ["L", "YCbCr"]:
|
|
self.mode = mode
|
|
a = mode, ""
|
|
|
|
if size:
|
|
scale = max(self.size[0] / size[0], self.size[1] / size[1])
|
|
for s in [8, 4, 2, 1]:
|
|
if scale >= s:
|
|
break
|
|
e = e[0], e[1], (e[2]-e[0]+s-1)/s+e[0], (e[3]-e[1]+s-1)/s+e[1]
|
|
self.size = ((self.size[0]+s-1)/s, (self.size[1]+s-1)/s)
|
|
scale = s
|
|
|
|
self.tile = [(d, e, o, a)]
|
|
self.decoderconfig = (scale, 1)
|
|
|
|
return self
|
|
|
|
def load_djpeg(self):
|
|
|
|
# ALTERNATIVE: handle JPEGs via the IJG command line utilities
|
|
|
|
import tempfile, os
|
|
file = tempfile.mktemp()
|
|
os.system("djpeg %s >%s" % (self.filename, file))
|
|
|
|
try:
|
|
self.im = Image.core.open_ppm(file)
|
|
finally:
|
|
try: os.unlink(file)
|
|
except: pass
|
|
|
|
self.mode = self.im.mode
|
|
self.size = self.im.size
|
|
|
|
self.tile = []
|
|
|
|
def _getexif(self):
|
|
# Extract EXIF information. This method is highly experimental,
|
|
# and is likely to be replaced with something better in a future
|
|
# version.
|
|
import TiffImagePlugin, StringIO
|
|
def fixup(value):
|
|
if len(value) == 1:
|
|
return value[0]
|
|
return value
|
|
# The EXIF record consists of a TIFF file embedded in a JPEG
|
|
# application marker (!).
|
|
try:
|
|
data = self.info["exif"]
|
|
except KeyError:
|
|
return None
|
|
file = StringIO.StringIO(data[6:])
|
|
head = file.read(8)
|
|
exif = {}
|
|
# process dictionary
|
|
info = TiffImagePlugin.ImageFileDirectory(head)
|
|
info.load(file)
|
|
for key, value in info.items():
|
|
exif[key] = fixup(value)
|
|
# get exif extension
|
|
try:
|
|
file.seek(exif[0x8769])
|
|
except KeyError:
|
|
pass
|
|
else:
|
|
info = TiffImagePlugin.ImageFileDirectory(head)
|
|
info.load(file)
|
|
for key, value in info.items():
|
|
exif[key] = fixup(value)
|
|
# get gpsinfo extension
|
|
try:
|
|
file.seek(exif[0x8825])
|
|
except KeyError:
|
|
pass
|
|
else:
|
|
info = TiffImagePlugin.ImageFileDirectory(head)
|
|
info.load(file)
|
|
exif[0x8825] = gps = {}
|
|
for key, value in info.items():
|
|
gps[key] = fixup(value)
|
|
return exif
|
|
|
|
# --------------------------------------------------------------------
|
|
# stuff to save JPEG files
|
|
|
|
RAWMODE = {
|
|
"1": "L",
|
|
"L": "L",
|
|
"RGB": "RGB",
|
|
"RGBA": "RGB",
|
|
"RGBX": "RGB",
|
|
"CMYK": "CMYK;I", # assume adobe conventions
|
|
"YCbCr": "YCbCr",
|
|
}
|
|
|
|
def _save(im, fp, filename):
|
|
|
|
try:
|
|
rawmode = RAWMODE[im.mode]
|
|
except KeyError:
|
|
raise IOError("cannot write mode %s as JPEG" % im.mode)
|
|
|
|
info = im.encoderinfo
|
|
|
|
dpi = info.get("dpi", (0, 0))
|
|
|
|
subsampling = info.get("subsampling", -1)
|
|
if subsampling == "4:4:4":
|
|
subsampling = 0
|
|
elif subsampling == "4:2:2":
|
|
subsampling = 1
|
|
elif subsampling == "4:1:1":
|
|
subsampling = 2
|
|
|
|
extra = ""
|
|
|
|
icc_profile = info.get("icc_profile")
|
|
if icc_profile:
|
|
ICC_OVERHEAD_LEN = 14
|
|
MAX_BYTES_IN_MARKER = 65533
|
|
MAX_DATA_BYTES_IN_MARKER = MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN
|
|
markers = []
|
|
while icc_profile:
|
|
markers.append(icc_profile[:MAX_DATA_BYTES_IN_MARKER])
|
|
icc_profile = icc_profile[MAX_DATA_BYTES_IN_MARKER:]
|
|
i = 1
|
|
for marker in markers:
|
|
size = struct.pack(">H", 2 + ICC_OVERHEAD_LEN + len(marker))
|
|
extra = extra + ("\xFF\xE2" + size + "ICC_PROFILE\0" + chr(i) + chr(len(markers)) + marker)
|
|
i = i + 1
|
|
|
|
# get keyword arguments
|
|
im.encoderconfig = (
|
|
info.get("quality", 0),
|
|
# "progressive" is the official name, but older documentation
|
|
# says "progression"
|
|
# FIXME: issue a warning if the wrong form is used (post-1.1.7)
|
|
info.has_key("progressive") or info.has_key("progression"),
|
|
info.get("smooth", 0),
|
|
info.has_key("optimize"),
|
|
info.get("streamtype", 0),
|
|
dpi[0], dpi[1],
|
|
subsampling,
|
|
extra,
|
|
)
|
|
|
|
ImageFile._save(im, fp, [("jpeg", (0,0)+im.size, 0, rawmode)])
|
|
|
|
def _save_cjpeg(im, fp, filename):
|
|
# ALTERNATIVE: handle JPEGs via the IJG command line utilities.
|
|
import os
|
|
file = im._dump()
|
|
os.system("cjpeg %s >%s" % (file, filename))
|
|
try: os.unlink(file)
|
|
except: pass
|
|
|
|
# -------------------------------------------------------------------q-
|
|
# Registry stuff
|
|
|
|
Image.register_open("JPEG", JpegImageFile, _accept)
|
|
Image.register_save("JPEG", _save)
|
|
|
|
Image.register_extension("JPEG", ".jfif")
|
|
Image.register_extension("JPEG", ".jpe")
|
|
Image.register_extension("JPEG", ".jpg")
|
|
Image.register_extension("JPEG", ".jpeg")
|
|
|
|
Image.register_mime("JPEG", "image/jpeg")
|