# # The Python Imaging Library. # $Id$ # # JPEG (JFIF) file handling # # See "Digital Compression and Coding of Continuous-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. # from __future__ import print_function import array import struct import io import warnings from . import Image, ImageFile, TiffImagePlugin from ._binary import i8, o8, i16be as i16 from .JpegPresets import presets from ._util import isStringType __version__ = "0.6" # # 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] == b"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 = i8(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] == b"Exif\0": # extract Exif information (incomplete) self.info["exif"] = s # FIXME: value will change elif marker == 0xFFE2 and s[:5] == b"FPXR\0": # extract FlashPix information (incomplete) self.info["flashpix"] = s # FIXME: value will change elif marker == 0xFFE2 and s[:12] == b"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] == b"Adobe": self.info["adobe"] = i16(s, 5) # extract Adobe custom properties try: adobe_transform = i8(s[1]) except: pass else: self.info["adobe_transform"] = adobe_transform elif marker == 0xFFE2 and s[:4] == b"MPF\0": # extract MPO information self.info["mp"] = s[4:] # offset is current location minus buffer size # plus constant header size self.info["mpoffset"] = self.fp.tell() - n + 4 # If DPI isn't in JPEG header, fetch from EXIF if "dpi" not in self.info and "exif" in self.info: exif = self._getexif() try: resolution_unit = exif[0x0128] x_resolution = exif[0x011A] try: dpi = x_resolution[0] / x_resolution[1] except TypeError: dpi = x_resolution if resolution_unit == 3: # cm # 1 dpcm = 2.54 dpi dpi *= 2.54 self.info["dpi"] = dpi, dpi except KeyError: self.info["dpi"] = 72, 72 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 = i8(s[0]) if self.bits != 8: raise SyntaxError("cannot handle %d-bit layers" % self.bits) self.layers = i8(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 i8(self.icclist[0][13]) == len(self.icclist): profile = [] for p in self.icclist: profile.append(p[14:]) icc_profile = b"".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], i8(t[1])//16, i8(t[1]) & 15, i8(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 = i8(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[0:1] == b"\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 i8(s) != 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 True: i = i8(s) if i == 0xFF: s = s + self.fp.read(1) i = i16(s) else: # Skip non-0xFF junk s = self.fp.read(1) continue if i in MARKER: 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 == 0xFFFF: # padded marker or junk; move on s = b"\xff" elif i == 0xFF00: # Skip extraneous data (escaped 0xFF) s = self.fp.read(1) else: raise SyntaxError("no marker found") def draft(self, mode, size): if len(self.tile) != 1: return # Protect from second call if self.decoderconfig: 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 = min(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, 0) return self def load_djpeg(self): # ALTERNATIVE: handle JPEGs via the IJG command line utilities import subprocess import tempfile import os f, path = tempfile.mkstemp() os.close(f) if os.path.exists(self.filename): subprocess.check_call(["djpeg", "-outfile", path, self.filename]) else: raise ValueError("Invalid Filename") try: _im = Image.open(path) _im.load() self.im = _im.im finally: try: os.unlink(path) except OSError: pass self.mode = self.im.mode self.size = self.im.size self.tile = [] def _getexif(self): return _getexif(self) def _getmp(self): return _getmp(self) def _fixup_dict(src_dict): # Helper function for _getexif() # returns a dict with any single item tuples/lists as individual values def _fixup(value): try: if len(value) == 1 and not isinstance(value, dict): return value[0] except: pass return value return {k: _fixup(v) for k, v in src_dict.items()} def _getexif(self): # Extract EXIF information. This method is highly experimental, # and is likely to be replaced with something better in a future # version. # The EXIF record consists of a TIFF file embedded in a JPEG # application marker (!). try: data = self.info["exif"] except KeyError: return None file = io.BytesIO(data[6:]) head = file.read(8) # process dictionary info = TiffImagePlugin.ImageFileDirectory_v1(head) info.load(file) exif = dict(_fixup_dict(info)) # get exif extension try: # exif field 0x8769 is an offset pointer to the location # of the nested embedded exif ifd. # It should be a long, but may be corrupted. file.seek(exif[0x8769]) except (KeyError, TypeError): pass else: info = TiffImagePlugin.ImageFileDirectory_v1(head) info.load(file) exif.update(_fixup_dict(info)) # get gpsinfo extension try: # exif field 0x8825 is an offset pointer to the location # of the nested embedded gps exif ifd. # It should be a long, but may be corrupted. file.seek(exif[0x8825]) except (KeyError, TypeError): pass else: info = TiffImagePlugin.ImageFileDirectory_v1(head) info.load(file) exif[0x8825] = _fixup_dict(info) return exif def _getmp(self): # Extract MP information. This method was inspired by the "highly # experimental" _getexif version that's been in use for years now, # itself based on the ImageFileDirectory class in the TIFF plug-in. # The MP record essentially consists of a TIFF file embedded in a JPEG # application marker. try: data = self.info["mp"] except KeyError: return None file_contents = io.BytesIO(data) head = file_contents.read(8) endianness = '>' if head[:4] == b'\x4d\x4d\x00\x2a' else '<' # process dictionary try: info = TiffImagePlugin.ImageFileDirectory_v2(head) info.load(file_contents) mp = dict(info) except: raise SyntaxError("malformed MP Index (unreadable directory)") # it's an error not to have a number of images try: quant = mp[0xB001] except KeyError: raise SyntaxError("malformed MP Index (no number of images)") # get MP entries mpentries = [] try: rawmpentries = mp[0xB002] for entrynum in range(0, quant): unpackedentry = struct.unpack_from( '{}LLLHH'.format(endianness), rawmpentries, entrynum * 16) labels = ('Attribute', 'Size', 'DataOffset', 'EntryNo1', 'EntryNo2') mpentry = dict(zip(labels, unpackedentry)) mpentryattr = { 'DependentParentImageFlag': bool(mpentry['Attribute'] & (1 << 31)), 'DependentChildImageFlag': bool(mpentry['Attribute'] & (1 << 30)), 'RepresentativeImageFlag': bool(mpentry['Attribute'] & (1 << 29)), 'Reserved': (mpentry['Attribute'] & (3 << 27)) >> 27, 'ImageDataFormat': (mpentry['Attribute'] & (7 << 24)) >> 24, 'MPType': mpentry['Attribute'] & 0x00FFFFFF } if mpentryattr['ImageDataFormat'] == 0: mpentryattr['ImageDataFormat'] = 'JPEG' else: raise SyntaxError("unsupported picture format in MPO") mptypemap = { 0x000000: 'Undefined', 0x010001: 'Large Thumbnail (VGA Equivalent)', 0x010002: 'Large Thumbnail (Full HD Equivalent)', 0x020001: 'Multi-Frame Image (Panorama)', 0x020002: 'Multi-Frame Image: (Disparity)', 0x020003: 'Multi-Frame Image: (Multi-Angle)', 0x030000: 'Baseline MP Primary Image' } mpentryattr['MPType'] = mptypemap.get(mpentryattr['MPType'], 'Unknown') mpentry['Attribute'] = mpentryattr mpentries.append(mpentry) mp[0xB002] = mpentries except KeyError: raise SyntaxError("malformed MP Index (bad MP Entry)") # Next we should try and parse the individual image unique ID list; # we don't because I've never seen this actually used in a real MPO # file and so can't test it. return mp # -------------------------------------------------------------------- # stuff to save JPEG files RAWMODE = { "1": "L", "L": "L", "RGB": "RGB", "RGBA": "RGB", "RGBX": "RGB", "CMYK": "CMYK;I", # assume adobe conventions "YCbCr": "YCbCr", } zigzag_index = (0, 1, 5, 6, 14, 15, 27, 28, 2, 4, 7, 13, 16, 26, 29, 42, 3, 8, 12, 17, 25, 30, 41, 43, 9, 11, 18, 24, 31, 40, 44, 53, 10, 19, 23, 32, 39, 45, 52, 54, 20, 22, 33, 38, 46, 51, 55, 60, 21, 34, 37, 47, 50, 56, 59, 61, 35, 36, 48, 49, 57, 58, 62, 63) samplings = {(1, 1, 1, 1, 1, 1): 0, (2, 1, 1, 1, 1, 1): 1, (2, 2, 1, 1, 1, 1): 2, } def convert_dict_qtables(qtables): qtables = [qtables[key] for key in range(len(qtables)) if key in qtables] for idx, table in enumerate(qtables): qtables[idx] = [table[i] for i in zigzag_index] return qtables def get_sampling(im): # There's no subsampling when image have only 1 layer # (grayscale images) or when they are CMYK (4 layers), # so set subsampling to default value. # # NOTE: currently Pillow can't encode JPEG to YCCK format. # If YCCK support is added in the future, subsampling code will have # to be updated (here and in JpegEncode.c) to deal with 4 layers. if not hasattr(im, 'layers') or im.layers in (1, 4): return -1 sampling = im.layer[0][1:3] + im.layer[1][1:3] + im.layer[2][1:3] return samplings.get(sampling, -1) def _save(im, fp, filename): try: rawmode = RAWMODE[im.mode] except KeyError: raise IOError("cannot write mode %s as JPEG" % im.mode) if im.mode == 'RGBA': warnings.warn( 'You are saving RGBA image as JPEG. The alpha channel will be ' 'discarded. This conversion is deprecated and will be disabled ' 'in Pillow 3.7. Please, convert the image to RGB explicitly.', DeprecationWarning ) info = im.encoderinfo dpi = [int(round(x)) for x in info.get("dpi", (0, 0))] quality = info.get("quality", 0) subsampling = info.get("subsampling", -1) qtables = info.get("qtables") if quality == "keep": quality = 0 subsampling = "keep" qtables = "keep" elif quality in presets: preset = presets[quality] quality = 0 subsampling = preset.get('subsampling', -1) qtables = preset.get('quantization') elif not isinstance(quality, int): raise ValueError("Invalid quality setting") else: if subsampling in presets: subsampling = presets[subsampling].get('subsampling', -1) if isStringType(qtables) and qtables in presets: qtables = presets[qtables].get('quantization') if subsampling == "4:4:4": subsampling = 0 elif subsampling == "4:2:2": subsampling = 1 elif subsampling == "4:1:1": subsampling = 2 elif subsampling == "keep": if im.format != "JPEG": raise ValueError( "Cannot use 'keep' when original image is not a JPEG") subsampling = get_sampling(im) def validate_qtables(qtables): if qtables is None: return qtables if isStringType(qtables): try: lines = [int(num) for line in qtables.splitlines() for num in line.split('#', 1)[0].split()] except ValueError: raise ValueError("Invalid quantization table") else: qtables = [lines[s:s+64] for s in range(0, len(lines), 64)] if isinstance(qtables, (tuple, list, dict)): if isinstance(qtables, dict): qtables = convert_dict_qtables(qtables) elif isinstance(qtables, tuple): qtables = list(qtables) if not (0 < len(qtables) < 5): raise ValueError("None or too many quantization tables") for idx, table in enumerate(qtables): try: if len(table) != 64: raise table = array.array('B', table) except TypeError: raise ValueError("Invalid quantization table") else: qtables[idx] = list(table) return qtables if qtables == "keep": if im.format != "JPEG": raise ValueError( "Cannot use 'keep' when original image is not a JPEG") qtables = getattr(im, "quantization", None) qtables = validate_qtables(qtables) extra = b"" 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 += (b"\xFF\xE2" + size + b"ICC_PROFILE\0" + o8(i) + o8(len(markers)) + marker) i += 1 # "progressive" is the official name, but older documentation # says "progression" # FIXME: issue a warning if the wrong form is used (post-1.1.7) progressive = info.get("progressive", False) or\ info.get("progression", False) optimize = info.get("optimize", False) # get keyword arguments im.encoderconfig = ( quality, progressive, info.get("smooth", 0), optimize, info.get("streamtype", 0), dpi[0], dpi[1], subsampling, qtables, extra, info.get("exif", b"") ) # if we optimize, libjpeg needs a buffer big enough to hold the whole image # in a shot. Guessing on the size, at im.size bytes. (raw pizel size is # channels*size, this is a value that's been used in a django patch. # https://github.com/matthewwithanm/django-imagekit/issues/50 bufsize = 0 if optimize or progressive: # CMYK can be bigger if im.mode == 'CMYK': bufsize = 4 * im.size[0] * im.size[1] # keep sets quality to 0, but the actual value may be high. elif quality >= 95 or quality == 0: bufsize = 2 * im.size[0] * im.size[1] else: bufsize = im.size[0] * im.size[1] # The exif info needs to be written as one block, + APP1, + one spare byte. # Ensure that our buffer is big enough bufsize = max(ImageFile.MAXBLOCK, bufsize, len(info.get("exif", b"")) + 5) ImageFile._save(im, fp, [("jpeg", (0, 0)+im.size, 0, rawmode)], bufsize) def _save_cjpeg(im, fp, filename): # ALTERNATIVE: handle JPEGs via the IJG command line utilities. import os import subprocess tempfile = im._dump() subprocess.check_call(["cjpeg", "-outfile", filename, tempfile]) try: os.unlink(tempfile) except OSError: pass ## # Factory for making JPEG and MPO instances def jpeg_factory(fp=None, filename=None): im = JpegImageFile(fp, filename) try: mpheader = im._getmp() if mpheader[45057] > 1: # It's actually an MPO from .MpoImagePlugin import MpoImageFile im = MpoImageFile(fp, filename) except (TypeError, IndexError): # It is really a JPEG pass except SyntaxError: warnings.warn("Image appears to be a malformed MPO file, it will be " "interpreted as a base JPEG file") return im # -------------------------------------------------------------------q- # Registry stuff Image.register_open(JpegImageFile.format, jpeg_factory, _accept) Image.register_save(JpegImageFile.format, _save) Image.register_extension(JpegImageFile.format, ".jfif") Image.register_extension(JpegImageFile.format, ".jpe") Image.register_extension(JpegImageFile.format, ".jpg") Image.register_extension(JpegImageFile.format, ".jpeg") Image.register_mime(JpegImageFile.format, "image/jpeg")