Pillow/PIL/TiffImagePlugin.py

#
# The Python Imaging Library.
# $Id$
#
# TIFF file handling
#
# TIFF is a flexible, if somewhat aged, image file format originally
# defined by Aldus.  Although TIFF supports a wide variety of pixel
# layouts and compression methods, the name doesn't really stand for
# "thousands of incompatible file formats," it just feels that way.
#
# To read TIFF data from a stream, the stream must be seekable.  For
# progressive decoding, make sure to use TIFF files where the tag
# directory is placed first in the file.
#
# History:
# 1995-09-01 fl   Created
# 1996-05-04 fl   Handle JPEGTABLES tag
# 1996-05-18 fl   Fixed COLORMAP support
# 1997-01-05 fl   Fixed PREDICTOR support
# 1997-08-27 fl   Added support for rational tags (from Perry Stoll)
# 1998-01-10 fl   Fixed seek/tell (from Jan Blom)
# 1998-07-15 fl   Use private names for internal variables
# 1999-06-13 fl   Rewritten for PIL 1.0 (1.0)
# 2000-10-11 fl   Additional fixes for Python 2.0 (1.1)
# 2001-04-17 fl   Fixed rewind support (seek to frame 0) (1.2)
# 2001-05-12 fl   Added write support for more tags (from Greg Couch) (1.3)
# 2001-12-18 fl   Added workaround for broken Matrox library
# 2002-01-18 fl   Don't mess up if photometric tag is missing (D. Alan Stewart)
# 2003-05-19 fl   Check FILLORDER tag
# 2003-09-26 fl   Added RGBa support
# 2004-02-24 fl   Added DPI support; fixed rational write support
# 2005-02-07 fl   Added workaround for broken Corel Draw 10 files
# 2006-01-09 fl   Added support for float/double tags (from Russell Nelson)
#
# Copyright (c) 1997-2006 by Secret Labs AB.  All rights reserved.
# Copyright (c) 1995-1997 by Fredrik Lundh
#
# See the README file for information on usage and redistribution.
#

from __future__ import print_function

__version__ = "1.3.5"
DEBUG = False # Needs to be merged with the new logging approach.

from PIL import Image, ImageFile
from PIL import ImagePalette
from PIL import _binary
from PIL._util import isStringType

import warnings
import array
import sys
import collections
import itertools
import os
import io

# Set these to true to force use of libtiff for reading or writing.
READ_LIBTIFF = False
WRITE_LIBTIFF = False

II = b"II"  # little-endian (Intel style)
MM = b"MM"  # big-endian (Motorola style)

i8 = _binary.i8
o8 = _binary.o8

if sys.byteorder == "little":
    native_prefix = II
else:
    native_prefix = MM

#
# --------------------------------------------------------------------
# Read TIFF files

il16 = _binary.i16le
il32 = _binary.i32le
ol16 = _binary.o16le
ol32 = _binary.o32le

ib16 = _binary.i16be
ib32 = _binary.i32be
ob16 = _binary.o16be
ob32 = _binary.o32be

# a few tag names, just to make the code below a bit more readable
IMAGEWIDTH = 256
IMAGELENGTH = 257
BITSPERSAMPLE = 258
COMPRESSION = 259
PHOTOMETRIC_INTERPRETATION = 262
FILLORDER = 266
IMAGEDESCRIPTION = 270
STRIPOFFSETS = 273
SAMPLESPERPIXEL = 277
ROWSPERSTRIP = 278
STRIPBYTECOUNTS = 279
X_RESOLUTION = 282
Y_RESOLUTION = 283
PLANAR_CONFIGURATION = 284
RESOLUTION_UNIT = 296
SOFTWARE = 305
DATE_TIME = 306
ARTIST = 315
PREDICTOR = 317
COLORMAP = 320
TILEOFFSETS = 324
EXTRASAMPLES = 338
SAMPLEFORMAT = 339
JPEGTABLES = 347
COPYRIGHT = 33432
IPTC_NAA_CHUNK = 33723  # newsphoto properties
PHOTOSHOP_CHUNK = 34377  # photoshop properties
ICCPROFILE = 34675
EXIFIFD = 34665
XMP = 700

# https://github.com/fiji/ImageJA/blob/master/src/main/java/ij/io/TiffDecoder.java
IMAGEJ_META_DATA_BYTE_COUNTS = 50838
IMAGEJ_META_DATA = 50839

COMPRESSION_INFO = {
    # Compression => pil compression name
    1: "raw",
    2: "tiff_ccitt",
    3: "group3",
    4: "group4",
    5: "tiff_lzw",
    6: "tiff_jpeg",  # obsolete
    7: "jpeg",
    8: "tiff_adobe_deflate",
    32771: "tiff_raw_16",  # 16-bit padding
    32773: "packbits",
    32809: "tiff_thunderscan",
    32946: "tiff_deflate",
    34676: "tiff_sgilog",
    34677: "tiff_sgilog24",
}

COMPRESSION_INFO_REV = dict([(v, k) for (k, v) in COMPRESSION_INFO.items()])

OPEN_INFO = {
    # (ByteOrder, PhotoInterpretation, SampleFormat, FillOrder, BitsPerSample,
    #  ExtraSamples) => mode, rawmode
    (II, 0, 1, 1, (1,), ()): ("1", "1;I"),
    (II, 0, 1, 2, (1,), ()): ("1", "1;IR"),
    (II, 0, 1, 1, (8,), ()): ("L", "L;I"),
    (II, 0, 1, 2, (8,), ()): ("L", "L;IR"),
    (II, 0, 3, 1, (32,), ()): ("F", "F;32F"),
    (II, 1, 1, 1, (1,), ()): ("1", "1"),
    (II, 1, 1, 1, (4,), ()): ("L", "L;4"),
    (II, 1, 1, 2, (1,), ()): ("1", "1;R"),
    (II, 1, 1, 1, (8,), ()): ("L", "L"),
    (II, 1, 1, 1, (8, 8), (2,)): ("LA", "LA"),
    (II, 1, 1, 2, (8,), ()): ("L", "L;R"),
    (II, 1, 1, 1, (12,), ()): ("I;16", "I;12"),
    (II, 1, 1, 1, (16,), ()): ("I;16", "I;16"),
    (II, 1, 2, 1, (16,), ()): ("I;16S", "I;16S"),
    (II, 1, 1, 1, (32,), ()): ("I", "I;32N"),
    (II, 1, 2, 1, (32,), ()): ("I", "I;32S"),
    (II, 1, 3, 1, (32,), ()): ("F", "F;32F"),
    (II, 2, 1, 1, (8, 8, 8), ()): ("RGB", "RGB"),
    (II, 2, 1, 2, (8, 8, 8), ()): ("RGB", "RGB;R"),
    (II, 2, 1, 1, (8, 8, 8, 8), ()): ("RGBA", "RGBA"),  # missing ExtraSamples
    (II, 2, 1, 1, (8, 8, 8, 8), (0,)): ("RGBX", "RGBX"),
    (II, 2, 1, 1, (8, 8, 8, 8), (1,)): ("RGBA", "RGBa"),
    (II, 2, 1, 1, (8, 8, 8, 8), (2,)): ("RGBA", "RGBA"),
    (II, 2, 1, 1, (8, 8, 8, 8), (999,)): ("RGBA", "RGBA"),  # Corel Draw 10
    (II, 3, 1, 1, (1,), ()): ("P", "P;1"),
    (II, 3, 1, 2, (1,), ()): ("P", "P;1R"),
    (II, 3, 1, 1, (2,), ()): ("P", "P;2"),
    (II, 3, 1, 2, (2,), ()): ("P", "P;2R"),
    (II, 3, 1, 1, (4,), ()): ("P", "P;4"),
    (II, 3, 1, 2, (4,), ()): ("P", "P;4R"),
    (II, 3, 1, 1, (8,), ()): ("P", "P"),
    (II, 3, 1, 1, (8, 8), (2,)): ("PA", "PA"),
    (II, 3, 1, 2, (8,), ()): ("P", "P;R"),
    (II, 5, 1, 1, (8, 8, 8, 8), ()): ("CMYK", "CMYK"),
    (II, 6, 1, 1, (8, 8, 8), ()): ("YCbCr", "YCbCr"),
    (II, 8, 1, 1, (8, 8, 8), ()): ("LAB", "LAB"),

    (MM, 0, 1, 1, (1,), ()): ("1", "1;I"),
    (MM, 0, 1, 2, (1,), ()): ("1", "1;IR"),
    (MM, 0, 1, 1, (8,), ()): ("L", "L;I"),
    (MM, 0, 1, 2, (8,), ()): ("L", "L;IR"),
    (MM, 1, 1, 1, (1,), ()): ("1", "1"),
    (MM, 1, 1, 2, (1,), ()): ("1", "1;R"),
    (MM, 1, 1, 1, (8,), ()): ("L", "L"),
    (MM, 1, 1, 1, (8, 8), (2,)): ("LA", "LA"),
    (MM, 1, 1, 2, (8,), ()): ("L", "L;R"),
    (MM, 1, 1, 1, (16,), ()): ("I;16B", "I;16B"),
    (MM, 1, 2, 1, (16,), ()): ("I;16BS", "I;16BS"),
    (MM, 1, 2, 1, (32,), ()): ("I;32BS", "I;32BS"),
    (MM, 1, 3, 1, (32,), ()): ("F", "F;32BF"),
    (MM, 2, 1, 1, (8, 8, 8), ()): ("RGB", "RGB"),
    (MM, 2, 1, 2, (8, 8, 8), ()): ("RGB", "RGB;R"),
    (MM, 2, 1, 1, (8, 8, 8, 8), (0,)): ("RGBX", "RGBX"),
    (MM, 2, 1, 1, (8, 8, 8, 8), (1,)): ("RGBA", "RGBa"),
    (MM, 2, 1, 1, (8, 8, 8, 8), (2,)): ("RGBA", "RGBA"),
    (MM, 2, 1, 1, (8, 8, 8, 8), (999,)): ("RGBA", "RGBA"),  # Corel Draw 10
    (MM, 3, 1, 1, (1,), ()): ("P", "P;1"),
    (MM, 3, 1, 2, (1,), ()): ("P", "P;1R"),
    (MM, 3, 1, 1, (2,), ()): ("P", "P;2"),
    (MM, 3, 1, 2, (2,), ()): ("P", "P;2R"),
    (MM, 3, 1, 1, (4,), ()): ("P", "P;4"),
    (MM, 3, 1, 2, (4,), ()): ("P", "P;4R"),
    (MM, 3, 1, 1, (8,), ()): ("P", "P"),
    (MM, 3, 1, 1, (8, 8), (2,)): ("PA", "PA"),
    (MM, 3, 1, 2, (8,), ()): ("P", "P;R"),
    (MM, 5, 1, 1, (8, 8, 8, 8), ()): ("CMYK", "CMYK"),
    (MM, 6, 1, 1, (8, 8, 8), ()): ("YCbCr", "YCbCr"),
    (MM, 8, 1, 1, (8, 8, 8), ()): ("LAB", "LAB"),

}

PREFIXES = [b"MM\000\052", b"II\052\000", b"II\xBC\000"]


def _accept(prefix):
    return prefix[:4] in PREFIXES


##
# Wrapper for TIFF IFDs.

class ImageFileDirectory(collections.MutableMapping):
    """ This class represents a TIFF tag directory.  To speed things
        up, we don't decode tags unless they're asked for.

        Exposes a dictionary interface of the tags in the directory
        ImageFileDirectory[key] = value
        value = ImageFileDirectory[key]

        Also contains a dictionary of tag types as read from the tiff
        image file, 'ImageFileDirectory.tagtype'


        Data Structures:
        'public'
        * self.tagtype = {} Key: numerical tiff tag number
                            Value: integer corresponding to the data type from
                            `TiffTags.TYPES`

        'internal'
        * self.tags = {}  Key: numerical tiff tag number
                          Value: Decoded data, Generally a tuple.
                            * If set from __setval__ -- always a tuple
                            * Numeric types -- always a tuple
                            * String type -- not a tuple, returned as string
                            * Undefined data -- not a tuple, returned as bytes
                            * Byte -- not a tuple, returned as byte.
        * self.tagdata = {} Key: numerical tiff tag number
                            Value: undecoded byte string from file


        Tags will be found in either self.tags or self.tagdata, but
        not both. The union of the two should contain all the tags
        from the Tiff image file.  External classes shouldn't
        reference these unless they're really sure what they're doing.
        """

    def __init__(self, prefix=II):
        """
        :prefix: 'II'|'MM'  tiff endianness
        """
        self.prefix = prefix[:2]
        if self.prefix == MM:
            self.i16, self.i32 = ib16, ib32
            self.o16, self.o32 = ob16, ob32
        elif self.prefix == II:
            self.i16, self.i32 = il16, il32
            self.o16, self.o32 = ol16, ol32
        else:
            raise SyntaxError("not a TIFF IFD")
        self.reset()

    def reset(self):
        #: Tags is an incomplete dictionary of the tags of the image.
        #: For a complete dictionary, use the as_dict method.
        self.tags = {}
        self.tagdata = {}
        self.tagtype = {}  # added 2008-06-05 by Florian Hoech
        self.next = None
        self.offset = None

    def __str__(self):
        return str(self.as_dict())

    def as_dict(self):
        """Return a dictionary of the image's tags."""
        return dict(self.items())

    def named(self):
        """
        Returns the complete tag dictionary, with named tags where possible.
        """
        from PIL import TiffTags
        result = {}
        for tag_code, value in self.items():
            tag_name = TiffTags.TAGS.get(tag_code, tag_code)
            result[tag_name] = value
        return result

    # dictionary API

    def __len__(self):
        return len(self.tagdata) + len(self.tags)

    def __getitem__(self, tag):
        try:
            return self.tags[tag]
        except KeyError:
            data = self.tagdata[tag]  # unpack on the fly
            type = self.tagtype[tag]
            size, handler = self.load_dispatch[type]
            self.tags[tag] = data = handler(self, data)
            del self.tagdata[tag]
            return data

    def getscalar(self, tag, default=None):
        try:
            value = self[tag]
            if len(value) != 1:
                if tag == SAMPLEFORMAT:
                    # work around broken (?) matrox library
                    # (from Ted Wright, via Bob Klimek)
                    raise KeyError  # use default
                raise ValueError("not a scalar")
            return value[0]
        except KeyError:
            if default is None:
                raise
            return default

    def __contains__(self, tag):
        return tag in self.tags or tag in self.tagdata

    if bytes is str:
        def has_key(self, tag):
            return tag in self

    def __setitem__(self, tag, value):
        # tags are tuples for integers
        # tags are not tuples for byte, string, and undefined data.
        # see load_*
        if not isinstance(value, tuple):
            value = (value,)
        self.tags[tag] = value

    def __delitem__(self, tag):
        self.tags.pop(tag, self.tagdata.pop(tag, None))

    def __iter__(self):
        return itertools.chain(self.tags.__iter__(), self.tagdata.__iter__())

    def items(self):
        keys = list(self.__iter__())
        values = [self[key] for key in keys]
        return zip(keys, values)

    # load primitives

    load_dispatch = {}

    def load_byte(self, data):
        return data
    load_dispatch[1] = (1, load_byte)

    def load_string(self, data):
        if data[-1:] == b'\0':
            data = data[:-1]
        return data.decode('latin-1', 'replace')
    load_dispatch[2] = (1, load_string)

    def load_short(self, data):
        l = []
        for i in range(0, len(data), 2):
            l.append(self.i16(data, i))
        return tuple(l)
    load_dispatch[3] = (2, load_short)

    def load_long(self, data):
        l = []
        for i in range(0, len(data), 4):
            l.append(self.i32(data, i))
        return tuple(l)
    load_dispatch[4] = (4, load_long)

    def load_rational(self, data):
        l = []
        for i in range(0, len(data), 8):
            l.append((self.i32(data, i), self.i32(data, i+4)))
        return tuple(l)
    load_dispatch[5] = (8, load_rational)

    def load_float(self, data):
        a = array.array("f", data)
        if self.prefix != native_prefix:
            a.byteswap()
        return tuple(a)
    load_dispatch[11] = (4, load_float)

    def load_double(self, data):
        a = array.array("d", data)
        if self.prefix != native_prefix:
            a.byteswap()
        return tuple(a)
    load_dispatch[12] = (8, load_double)

    def load_undefined(self, data):
        # Untyped data
        return data
    load_dispatch[7] = (1, load_undefined)

    def load(self, fp):
        # load tag dictionary

        self.reset()
        self.offset = fp.tell()

        i16 = self.i16
        i32 = self.i32

        for i in range(i16(fp.read(2))):

            ifd = fp.read(12)
            if len(ifd) != 12:
                warnings.warn("Possibly corrupt EXIF data.  "
                              "Expecting to read 12 bytes but only got %d."
                              % (len(ifd)))
                continue

            tag, typ = i16(ifd), i16(ifd, 2)

            if DEBUG:
                from PIL import TiffTags
                tagname = TiffTags.TAGS.get(tag, "unknown")
                typname = TiffTags.TYPES.get(typ, "unknown")
                print("tag: %s (%d)" % (tagname, tag), end=' ')
                print("- type: %s (%d)" % (typname, typ), end=' ')

            try:
                dispatch = self.load_dispatch[typ]
            except KeyError:
                if DEBUG:
                    print("- unsupported type", typ)
                continue  # ignore unsupported type

            size, handler = dispatch

            size = size * i32(ifd, 4)

            # Get and expand tag value
            if size > 4:
                here = fp.tell()
                if DEBUG:
                    print("Tag Location: %s" % here)
                fp.seek(i32(ifd, 8))
                if DEBUG:
                    print("Data Location: %s" % fp.tell())
                data = ImageFile._safe_read(fp, size)
                fp.seek(here)
            else:
                data = ifd[8:8+size]

            if len(data) != size:
                warnings.warn("Possibly corrupt EXIF data.  "
                              "Expecting to read %d bytes but only got %d. "
                              "Skipping tag %s" % (size, len(data), tag))
                continue

            self.tagdata[tag] = data
            self.tagtype[tag] = typ

            if DEBUG:
                if tag in (COLORMAP, IPTC_NAA_CHUNK, PHOTOSHOP_CHUNK,
                           ICCPROFILE, XMP):
                    print("- value: <table: %d bytes>" % size)
                else:
                    print("- value:", self[tag])

        ifd = fp.read(4)
        if len(ifd) != 4:
            warnings.warn("Possibly corrupt EXIF data.  "
                          "Expecting to read 4 bytes but only got %d."
                          % (len(ifd)))
            return

        self.next = i32(ifd)

    # save primitives

    def save(self, fp):

        o16 = self.o16
        o32 = self.o32

        fp.write(o16(len(self.tags)))

        # always write in ascending tag order
        tags = sorted(self.tags.items())

        directory = []
        append = directory.append

        offset = fp.tell() + len(self.tags) * 12 + 4

        stripoffsets = None

        # pass 1: convert tags to binary format
        for tag, value in tags:

            typ = None

            if tag in self.tagtype:
                typ = self.tagtype[tag]

            if DEBUG:
                print ("Tag %s, Type: %s, Value: %s" % (tag, typ, value))

            if typ == 1:
                # byte data
                if isinstance(value, tuple):
                    data = value = value[-1]
                else:
                    data = value
            elif typ == 7:
                # untyped data
                data = value = b"".join(value)
            elif typ in (11, 12):
                # float value
                tmap = {11: 'f', 12: 'd'}
                if not isinstance(value, tuple):
                    value = (value,)
                a = array.array(tmap[typ], value)
                if self.prefix != native_prefix:
                    a.byteswap()
                data = a.tostring()
            elif isStringType(value[0]):
                # string data
                if isinstance(value, tuple):
                    value = value[-1]
                typ = 2
                # was b'\0'.join(str), which led to \x00a\x00b sorts
                # of strings which I don't see in in the wild tiffs
                # and doesn't match the tiff spec: 8-bit byte that
                # contains a 7-bit ASCII code; the last byte must be
                # NUL (binary zero). Also, I don't think this was well
                # exercised before.
                data = value = b"" + value.encode('ascii', 'replace') + b"\0"
            else:
                # integer data
                if tag == STRIPOFFSETS:
                    stripoffsets = len(directory)
                    typ = 4  # to avoid catch-22
                elif tag in (X_RESOLUTION, Y_RESOLUTION) or typ == 5:
                    # identify rational data fields
                    typ = 5
                    if isinstance(value[0], tuple):
                        # long name for flatten
                        value = tuple(itertools.chain.from_iterable(value))
                elif not typ:
                    typ = 3
                    for v in value:
                        if v >= 65536:
                            typ = 4
                if typ == 3:
                    data = b"".join(map(o16, value))
                else:
                    data = b"".join(map(o32, value))

            if DEBUG:
                from PIL import TiffTags
                tagname = TiffTags.TAGS.get(tag, "unknown")
                typname = TiffTags.TYPES.get(typ, "unknown")
                print("save: %s (%d)" % (tagname, tag), end=' ')
                print("- type: %s (%d)" % (typname, typ), end=' ')
                if tag in (COLORMAP, IPTC_NAA_CHUNK, PHOTOSHOP_CHUNK,
                           ICCPROFILE, XMP):
                    size = len(data)
                    print("- value: <table: %d bytes>" % size)
                else:
                    print("- value:", value)

            # figure out if data fits into the directory
            if len(data) == 4:
                append((tag, typ, len(value), data, b""))
            elif len(data) < 4:
                append((tag, typ, len(value), data + (4-len(data))*b"\0", b""))
            else:
                count = len(value)
                if typ == 5:
                    count = count // 2        # adjust for rational data field

                append((tag, typ, count, o32(offset), data))
                offset += len(data)
                if offset & 1:
                    offset += 1  # word padding

        # update strip offset data to point beyond auxiliary data
        if stripoffsets is not None:
            tag, typ, count, value, data = directory[stripoffsets]
            assert not data, "multistrip support not yet implemented"
            value = o32(self.i32(value) + offset)
            directory[stripoffsets] = tag, typ, count, value, data

        # pass 2: write directory to file
        for tag, typ, count, value, data in directory:
            if DEBUG > 1:
                print(tag, typ, count, repr(value), repr(data))
            fp.write(o16(tag) + o16(typ) + o32(count) + value)

        # -- overwrite here for multi-page --
        fp.write(b"\0\0\0\0")  # end of directory

        # pass 3: write auxiliary data to file
        for tag, typ, count, value, data in directory:
            fp.write(data)
            if len(data) & 1:
                fp.write(b"\0")

        return offset


##
# Image plugin for TIFF files.

class TiffImageFile(ImageFile.ImageFile):

    format = "TIFF"
    format_description = "Adobe TIFF"

    def _open(self):
        "Open the first image in a TIFF file"

        # Header
        ifh = self.fp.read(8)

        if ifh[:4] not in PREFIXES:
            raise SyntaxError("not a TIFF file")

        # image file directory (tag dictionary)
        self.tag = self.ifd = ImageFileDirectory(ifh[:2])

        # setup frame pointers
        self.__first = self.__next = self.ifd.i32(ifh, 4)
        self.__frame = -1
        self.__fp = self.fp
        self._frame_pos = []
        self._n_frames = None
        self._is_animated = None

        if DEBUG:
            print ("*** TiffImageFile._open ***")
            print ("- __first:", self.__first)
            print ("- ifh: ", ifh)

        # and load the first frame
        self._seek(0)

    @property
    def n_frames(self):
        if self._n_frames is None:
            current = self.tell()
            try:
                while True:
                    self._seek(self.tell() + 1)
            except EOFError:
                self._n_frames = self.tell() + 1
            self.seek(current)
        return self._n_frames

    @property
    def is_animated(self):
        if self._is_animated is None:
            current = self.tell()

            try:
                self.seek(1)
                self._is_animated = True
            except EOFError:
                self._is_animated = False

            self.seek(current)
        return self._is_animated

    def seek(self, frame):
        "Select a given frame as current image"
        self._seek(max(frame, 0))  # Questionable backwards compatibility.
        # Create a new core image object on second and
        # subsequent frames in the image. Image may be
        # different size/mode.
        Image._decompression_bomb_check(self.size)
        self.im = Image.core.new(self.mode, self.size)

    def _seek(self, frame):
        self.fp = self.__fp
        while len(self._frame_pos) <= frame:
            if not self.__next:
                raise EOFError("no more images in TIFF file")
            if DEBUG:
                print("Seeking to frame %s, on frame %s, __next %s, location: %s" %
                      (frame, self.__frame, self.__next, self.fp.tell()))
            # reset python3 buffered io handle in case fp
            # was passed to libtiff, invalidating the buffer
            self.fp.tell()
            self.fp.seek(self.__next)
            self._frame_pos.append(self.__next)
            if DEBUG:
                print("Loading tags, location: %s" % self.fp.tell())
            self.tag.load(self.fp)
            self.__next = self.tag.next
            self.__frame += 1
        self.fp.seek(self._frame_pos[frame])
        self.tag.load(self.fp)
        self.__frame = frame
        self._setup()

    def tell(self):
        "Return the current frame number"
        return self.__frame

    def _decoder(self, rawmode, layer, tile=None):
        "Setup decoder contexts"

        args = None
        if rawmode == "RGB" and self._planar_configuration == 2:
            rawmode = rawmode[layer]
        compression = self._compression
        if compression == "raw":
            args = (rawmode, 0, 1)
        elif compression == "jpeg":
            args = rawmode, ""
            if JPEGTABLES in self.tag:
                # Hack to handle abbreviated JPEG headers
                self.tile_prefix = self.tag[JPEGTABLES]
        elif compression == "packbits":
            args = rawmode
        elif compression == "tiff_lzw":
            args = rawmode
            if 317 in self.tag:
                # Section 14: Differencing Predictor
                self.decoderconfig = (self.tag[PREDICTOR][0],)

        if ICCPROFILE in self.tag:
            self.info['icc_profile'] = self.tag[ICCPROFILE]

        return args

    def _load_libtiff(self):
        """ Overload method triggered when we detect a compressed tiff
            Calls out to libtiff """

        pixel = Image.Image.load(self)

        if self.tile is None:
            raise IOError("cannot load this image")
        if not self.tile:
            return pixel

        self.load_prepare()

        if not len(self.tile) == 1:
            raise IOError("Not exactly one tile")

        # (self._compression, (extents tuple),
        #   0, (rawmode, self._compression, fp))
        extents = self.tile[0][1]
        args = self.tile[0][3] + (self.ifd.offset,)
        decoder = Image._getdecoder(self.mode, 'libtiff', args,
                                    self.decoderconfig)
        try:
            decoder.setimage(self.im, extents)
        except ValueError:
            raise IOError("Couldn't set the image")

        if hasattr(self.fp, "getvalue"):
            # We've got a stringio like thing passed in. Yay for all in memory.
            # The decoder needs the entire file in one shot, so there's not
            # a lot we can do here other than give it the entire file.
            # unless we could do something like get the address of the
            # underlying string for stringio.
            #
            # Rearranging for supporting byteio items, since they have a fileno
            # that returns an IOError if there's no underlying fp. Easier to
            # deal with here by reordering.
            if DEBUG:
                print ("have getvalue. just sending in a string from getvalue")
            n, err = decoder.decode(self.fp.getvalue())
        elif hasattr(self.fp, "fileno"):
            # we've got a actual file on disk, pass in the fp.
            if DEBUG:
                print ("have fileno, calling fileno version of the decoder.")
            self.fp.seek(0)
            # 4 bytes, otherwise the trace might error out
            n, err = decoder.decode(b"fpfp")
        else:
            # we have something else.
            if DEBUG:
                print ("don't have fileno or getvalue. just reading")
            # UNDONE -- so much for that buffer size thing.
            n, err = decoder.decode(self.fp.read())

        self.tile = []
        self.readonly = 0
        # libtiff closed the fp in a, we need to close self.fp, if possible
        if hasattr(self.fp, 'close'):
            if not self.__next:
                self.fp.close()
        self.fp = None  # might be shared

        if err < 0:
            raise IOError(err)

        self.load_end()

        return Image.Image.load(self)

    def _setup(self):
        "Setup this image object based on current tags"

        if 0xBC01 in self.tag:
            raise IOError("Windows Media Photo files not yet supported")

        getscalar = self.tag.getscalar

        # extract relevant tags
        self._compression = COMPRESSION_INFO[getscalar(COMPRESSION, 1)]
        self._planar_configuration = getscalar(PLANAR_CONFIGURATION, 1)

        # photometric is a required tag, but not everyone is reading
        # the specification
        photo = getscalar(PHOTOMETRIC_INTERPRETATION, 0)

        fillorder = getscalar(FILLORDER, 1)

        if DEBUG:
            print("*** Summary ***")
            print("- compression:", self._compression)
            print("- photometric_interpretation:", photo)
            print("- planar_configuration:", self._planar_configuration)
            print("- fill_order:", fillorder)

        # size
        xsize = getscalar(IMAGEWIDTH)
        ysize = getscalar(IMAGELENGTH)
        self.size = xsize, ysize

        if DEBUG:
            print("- size:", self.size)

        format = getscalar(SAMPLEFORMAT, 1)

        # mode: check photometric interpretation and bits per pixel
        key = (
            self.tag.prefix, photo, format, fillorder,
            self.tag.get(BITSPERSAMPLE, (1,)),
            self.tag.get(EXTRASAMPLES, ())
            )
        if DEBUG:
            print("format key:", key)
        try:
            self.mode, rawmode = OPEN_INFO[key]
        except KeyError:
            if DEBUG:
                print("- unsupported format")
            raise SyntaxError("unknown pixel mode")

        if DEBUG:
            print("- raw mode:", rawmode)
            print("- pil mode:", self.mode)

        self.info["compression"] = self._compression

        xres = getscalar(X_RESOLUTION, (1, 1))
        yres = getscalar(Y_RESOLUTION, (1, 1))

        if xres and not isinstance(xres, tuple):
            xres = (xres, 1.)
        if yres and not isinstance(yres, tuple):
            yres = (yres, 1.)
        if xres and yres:
            xres = xres[0] / (xres[1] or 1)
            yres = yres[0] / (yres[1] or 1)
            resunit = getscalar(RESOLUTION_UNIT, 1)
            if resunit == 2:  # dots per inch
                self.info["dpi"] = xres, yres
            elif resunit == 3:  # dots per centimeter. convert to dpi
                self.info["dpi"] = xres * 2.54, yres * 2.54
            else:  # No absolute unit of measurement
                self.info["resolution"] = xres, yres

        # build tile descriptors
        x = y = l = 0
        self.tile = []
        if STRIPOFFSETS in self.tag:
            # striped image
            offsets = self.tag[STRIPOFFSETS]
            h = getscalar(ROWSPERSTRIP, ysize)
            w = self.size[0]
            if READ_LIBTIFF or self._compression in ["tiff_ccitt", "group3",
                                                     "group4", "tiff_jpeg",
                                                     "tiff_adobe_deflate",
                                                     "tiff_thunderscan",
                                                     "tiff_deflate",
                                                     "tiff_sgilog",
                                                     "tiff_sgilog24",
                                                     "tiff_raw_16"]:
                # if DEBUG:
                #     print "Activating g4 compression for whole file"

                # Decoder expects entire file as one tile.
                # There's a buffer size limit in load (64k)
                # so large g4 images will fail if we use that
                # function.
                #
                # Setup the one tile for the whole image, then
                # replace the existing load function with our
                # _load_libtiff function.

                self.load = self._load_libtiff

                # To be nice on memory footprint, if there's a
                # file descriptor, use that instead of reading
                # into a string in python.

                # libtiff closes the file descriptor, so pass in a dup.
                try:
                    fp = hasattr(self.fp, "fileno") and \
                        os.dup(self.fp.fileno())
                    # flush the file descriptor, prevents error on pypy 2.4+
                    # should also eliminate the need for fp.tell for py3
                    # in _seek
                    self.fp.flush()
                except IOError:
                    # io.BytesIO have a fileno, but returns an IOError if
                    # it doesn't use a file descriptor.
                    fp = False

                # libtiff handles the fillmode for us, so 1;IR should
                # actually be 1;I. Including the R double reverses the
                # bits, so stripes of the image are reversed.  See
                # https://github.com/python-pillow/Pillow/issues/279
                if fillorder == 2:
                    key = (
                        self.tag.prefix, photo, format, 1,
                        self.tag.get(BITSPERSAMPLE, (1,)),
                        self.tag.get(EXTRASAMPLES, ())
                        )
                    if DEBUG:
                        print("format key:", key)
                    # this should always work, since all the
                    # fillorder==2 modes have a corresponding
                    # fillorder=1 mode
                    self.mode, rawmode = OPEN_INFO[key]
                # libtiff always returns the bytes in native order.
                # we're expecting image byte order. So, if the rawmode
                # contains I;16, we need to convert from native to image
                # byte order.
                if self.mode in ('I;16B', 'I;16') and 'I;16' in rawmode:
                    rawmode = 'I;16N'

                # Offset in the tile tuple is 0, we go from 0,0 to
                # w,h, and we only do this once -- eds
                a = (rawmode, self._compression, fp)
                self.tile.append(
                    (self._compression,
                     (0, 0, w, ysize),
                     0, a))
                a = None

            else:
                for i in range(len(offsets)):
                    a = self._decoder(rawmode, l, i)
                    self.tile.append(
                        (self._compression,
                            (0, min(y, ysize), w, min(y+h, ysize)),
                            offsets[i], a))
                    if DEBUG:
                        print ("tiles: ", self.tile)
                    y = y + h
                    if y >= self.size[1]:
                        x = y = 0
                        l += 1
                    a = None
        elif TILEOFFSETS in self.tag:
            # tiled image
            w = getscalar(322)
            h = getscalar(323)
            a = None
            for o in self.tag[TILEOFFSETS]:
                if not a:
                    a = self._decoder(rawmode, l)
                # FIXME: this doesn't work if the image size
                # is not a multiple of the tile size...
                self.tile.append(
                    (self._compression,
                        (x, y, x+w, y+h),
                        o, a))
                x = x + w
                if x >= self.size[0]:
                    x, y = 0, y + h
                    if y >= self.size[1]:
                        x = y = 0
                        l += 1
                        a = None
        else:
            if DEBUG:
                print("- unsupported data organization")
            raise SyntaxError("unknown data organization")

        # fixup palette descriptor

        if self.mode == "P":
            palette = [o8(b // 256) for b in self.tag[COLORMAP]]
            self.palette = ImagePalette.raw("RGB;L", b"".join(palette))
#
# --------------------------------------------------------------------
# Write TIFF files

# little endian is default except for image modes with
# explicit big endian byte-order

SAVE_INFO = {
    # mode => rawmode, byteorder, photometrics,
    #           sampleformat, bitspersample, extra
    "1": ("1", II, 1, 1, (1,), None),
    "L": ("L", II, 1, 1, (8,), None),
    "LA": ("LA", II, 1, 1, (8, 8), 2),
    "P": ("P", II, 3, 1, (8,), None),
    "PA": ("PA", II, 3, 1, (8, 8), 2),
    "I": ("I;32S", II, 1, 2, (32,), None),
    "I;16": ("I;16", II, 1, 1, (16,), None),
    "I;16S": ("I;16S", II, 1, 2, (16,), None),
    "F": ("F;32F", II, 1, 3, (32,), None),
    "RGB": ("RGB", II, 2, 1, (8, 8, 8), None),
    "RGBX": ("RGBX", II, 2, 1, (8, 8, 8, 8), 0),
    "RGBA": ("RGBA", II, 2, 1, (8, 8, 8, 8), 2),
    "CMYK": ("CMYK", II, 5, 1, (8, 8, 8, 8), None),
    "YCbCr": ("YCbCr", II, 6, 1, (8, 8, 8), None),
    "LAB": ("LAB", II, 8, 1, (8, 8, 8), None),

    "I;32BS": ("I;32BS", MM, 1, 2, (32,), None),
    "I;16B": ("I;16B", MM, 1, 1, (16,), None),
    "I;16BS": ("I;16BS", MM, 1, 2, (16,), None),
    "F;32BF": ("F;32BF", MM, 1, 3, (32,), None),
}


def _cvt_res(value):
    # convert value to TIFF rational number -- (numerator, denominator)
    if isinstance(value, collections.Sequence):
        assert(len(value) % 2 == 0)
        return value
    if isinstance(value, int):
        return (value, 1)
    value = float(value)
    return (int(value * 65536), 65536)


def _save(im, fp, filename):

    try:
        rawmode, prefix, photo, format, bits, extra = SAVE_INFO[im.mode]
    except KeyError:
        raise IOError("cannot write mode %s as TIFF" % im.mode)

    ifd = ImageFileDirectory(prefix)

    compression = im.encoderinfo.get('compression', im.info.get('compression',
                                     'raw'))

    libtiff = WRITE_LIBTIFF or compression != 'raw'

    # required for color libtiff images
    ifd[PLANAR_CONFIGURATION] = getattr(im, '_planar_configuration', 1)

    # -- multi-page -- skip TIFF header on subsequent pages
    if not libtiff and fp.tell() == 0:
        # tiff header (write via IFD to get everything right)
        # PIL always starts the first IFD at offset 8
        fp.write(ifd.prefix + ifd.o16(42) + ifd.o32(8))

    ifd[IMAGEWIDTH] = im.size[0]
    ifd[IMAGELENGTH] = im.size[1]

    # write any arbitrary tags passed in as an ImageFileDirectory
    info = im.encoderinfo.get("tiffinfo", {})
    if DEBUG:
        print("Tiffinfo Keys: %s" % info.keys)
    keys = list(info.keys())
    for key in keys:
        ifd[key] = info.get(key)
        try:
            ifd.tagtype[key] = info.tagtype[key]
        except:
            pass  # might not be an IFD, Might not have populated type

    # additions written by Greg Couch, gregc@cgl.ucsf.edu
    # inspired by image-sig posting from Kevin Cazabon, kcazabon@home.com
    if hasattr(im, 'tag'):
        # preserve tags from original TIFF image file
        for key in (RESOLUTION_UNIT, X_RESOLUTION, Y_RESOLUTION,
                    IPTC_NAA_CHUNK, PHOTOSHOP_CHUNK, XMP):
            if key in im.tag:
                ifd[key] = im.tag[key]
            ifd.tagtype[key] = im.tag.tagtype.get(key, None)

        # preserve ICC profile (should also work when saving other formats
        # which support profiles as TIFF) -- 2008-06-06 Florian Hoech
        if "icc_profile" in im.info:
            ifd[ICCPROFILE] = im.info["icc_profile"]

    for key, name, cvt in [
            (IMAGEDESCRIPTION, "description", lambda x: x),
            (X_RESOLUTION, "resolution", _cvt_res),
            (Y_RESOLUTION, "resolution", _cvt_res),
            (X_RESOLUTION, "x_resolution", _cvt_res),
            (Y_RESOLUTION, "y_resolution", _cvt_res),
            (RESOLUTION_UNIT, "resolution_unit",
             lambda x: {"inch": 2, "cm": 3, "centimeter": 3}.get(x, 1)),
            (SOFTWARE, "software", lambda x: x),
            (DATE_TIME, "date_time", lambda x: x),
            (ARTIST, "artist", lambda x: x),
            (COPYRIGHT, "copyright", lambda x: x)]:
        name_with_spaces = name.replace("_", " ")
        if "_" in name and name_with_spaces in im.encoderinfo:
            warnings.warn("%r is deprecated; use %r instead" %
                          (name_with_spaces, name), DeprecationWarning)
            ifd[key] = cvt(im.encoderinfo[name.replace("_", " ")])
        if name in im.encoderinfo:
            ifd[key] = cvt(im.encoderinfo[name])

    dpi = im.encoderinfo.get("dpi")
    if dpi:
        ifd[RESOLUTION_UNIT] = 2
        ifd[X_RESOLUTION] = _cvt_res(dpi[0])
        ifd[Y_RESOLUTION] = _cvt_res(dpi[1])

    if bits != (1,):
        ifd[BITSPERSAMPLE] = bits
        if len(bits) != 1:
            ifd[SAMPLESPERPIXEL] = len(bits)
    if extra is not None:
        ifd[EXTRASAMPLES] = extra
    if format != 1:
        ifd[SAMPLEFORMAT] = format

    ifd[PHOTOMETRIC_INTERPRETATION] = photo

    if im.mode == "P":
        lut = im.im.getpalette("RGB", "RGB;L")
        ifd[COLORMAP] = tuple(i8(v) * 256 for v in lut)

    # data orientation
    stride = len(bits) * ((im.size[0]*bits[0]+7)//8)
    ifd[ROWSPERSTRIP] = im.size[1]
    ifd[STRIPBYTECOUNTS] = stride * im.size[1]
    ifd[STRIPOFFSETS] = 0  # this is adjusted by IFD writer
    # no compression by default:
    ifd[COMPRESSION] = COMPRESSION_INFO_REV.get(compression, 1)

    if libtiff:
        if DEBUG:
            print ("Saving using libtiff encoder")
            print (ifd.items())
        _fp = 0
        if hasattr(fp, "fileno"):
            try:
                fp.seek(0)
                _fp = os.dup(fp.fileno())
            except io.UnsupportedOperation:
                pass

        # ICC Profile crashes.
        blocklist = [STRIPOFFSETS, STRIPBYTECOUNTS, ROWSPERSTRIP, ICCPROFILE]
        atts = {}
        # bits per sample is a single short in the tiff directory, not a list.
        atts[BITSPERSAMPLE] = bits[0]
        # Merge the ones that we have with (optional) more bits from
        # the original file, e.g x,y resolution so that we can
        # save(load('')) == original file.
        for k, v in itertools.chain(ifd.items(),
                                    getattr(im, 'ifd', {}).items()):
            if k not in atts and k not in blocklist:
                if type(v[0]) == tuple and len(v) > 1:
                    # A tuple of more than one rational tuples
                    # flatten to floats,
                    # following tiffcp.c->cpTag->TIFF_RATIONAL
                    atts[k] = [float(elt[0])/float(elt[1]) for elt in v]
                    continue
                if type(v[0]) == tuple and len(v) == 1:
                    # A tuple of one rational tuples
                    # flatten to floats,
                    # following tiffcp.c->cpTag->TIFF_RATIONAL
                    atts[k] = float(v[0][0])/float(v[0][1])
                    continue
                if (type(v) == tuple and
                        (len(v) > 2 or
                            (len(v) == 2 and v[1] == 0))):
                    # List of ints?
                    # Avoid divide by zero in next if-clause
                    if type(v[0]) in (int, float):
                        atts[k] = list(v)
                    continue
                if type(v) == tuple and len(v) == 2:
                    # one rational tuple
                    # flatten to float,
                    # following tiffcp.c->cpTag->TIFF_RATIONAL
                    atts[k] = float(v[0])/float(v[1])
                    continue
                if type(v) == tuple and len(v) == 1:
                    v = v[0]
                    # drop through
                if isStringType(v):
                    atts[k] = bytes(v.encode('ascii', 'replace')) + b"\0"
                    continue
                else:
                    # int or similar
                    atts[k] = v

        if DEBUG:
            print (atts)

        # libtiff always expects the bytes in native order.
        # we're storing image byte order. So, if the rawmode
        # contains I;16, we need to convert from native to image
        # byte order.
        if im.mode in ('I;16B', 'I;16'):
            rawmode = 'I;16N'

        a = (rawmode, compression, _fp, filename, atts)
        # print (im.mode, compression, a, im.encoderconfig)
        e = Image._getencoder(im.mode, 'libtiff', a, im.encoderconfig)
        e.setimage(im.im, (0, 0)+im.size)
        while True:
            # undone, change to self.decodermaxblock:
            l, s, d = e.encode(16*1024)
            if not _fp:
                fp.write(d)
            if s:
                break
        if s < 0:
            raise IOError("encoder error %d when writing image file" % s)

    else:
        offset = ifd.save(fp)

        ImageFile._save(im, fp, [
            ("raw", (0, 0)+im.size, offset, (rawmode, stride, 1))
            ])

    # -- helper for multi-page save --
    if "_debug_multipage" in im.encoderinfo:
        # just to access o32 and o16 (using correct byte order)
        im._debug_multipage = ifd

#
# --------------------------------------------------------------------
# Register

Image.register_open("TIFF", TiffImageFile, _accept)
Image.register_save("TIFF", _save)

Image.register_extension("TIFF", ".tif")
Image.register_extension("TIFF", ".tiff")

Image.register_mime("TIFF", "image/tiff")