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authorLibravatarLibravatar Biswakalyan Bhuyan <biswa@surgot.in> 2022-11-13 23:46:45 +0530
committerLibravatarLibravatar Biswakalyan Bhuyan <biswa@surgot.in> 2022-11-13 23:46:45 +0530
commit9468226a9e2e2ab8cdd599f1d8538e860ca86120 (patch)
tree0a77ada226d6db80639f96b438bf83e4e756edb5 /env/lib/python3.10/site-packages/PIL/PngImagePlugin.py
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+#
+# The Python Imaging Library.
+# $Id$
+#
+# PNG support code
+#
+# See "PNG (Portable Network Graphics) Specification, version 1.0;
+# W3C Recommendation", 1996-10-01, Thomas Boutell (ed.).
+#
+# history:
+# 1996-05-06 fl Created (couldn't resist it)
+# 1996-12-14 fl Upgraded, added read and verify support (0.2)
+# 1996-12-15 fl Separate PNG stream parser
+# 1996-12-29 fl Added write support, added getchunks
+# 1996-12-30 fl Eliminated circular references in decoder (0.3)
+# 1998-07-12 fl Read/write 16-bit images as mode I (0.4)
+# 2001-02-08 fl Added transparency support (from Zircon) (0.5)
+# 2001-04-16 fl Don't close data source in "open" method (0.6)
+# 2004-02-24 fl Don't even pretend to support interlaced files (0.7)
+# 2004-08-31 fl Do basic sanity check on chunk identifiers (0.8)
+# 2004-09-20 fl Added PngInfo chunk container
+# 2004-12-18 fl Added DPI read support (based on code by Niki Spahiev)
+# 2008-08-13 fl Added tRNS support for RGB images
+# 2009-03-06 fl Support for preserving ICC profiles (by Florian Hoech)
+# 2009-03-08 fl Added zTXT support (from Lowell Alleman)
+# 2009-03-29 fl Read interlaced PNG files (from Conrado Porto Lopes Gouvua)
+#
+# Copyright (c) 1997-2009 by Secret Labs AB
+# Copyright (c) 1996 by Fredrik Lundh
+#
+# See the README file for information on usage and redistribution.
+#
+
+import itertools
+import logging
+import re
+import struct
+import warnings
+import zlib
+from enum import IntEnum
+
+from . import Image, ImageChops, ImageFile, ImagePalette, ImageSequence
+from ._binary import i16be as i16
+from ._binary import i32be as i32
+from ._binary import o8
+from ._binary import o16be as o16
+from ._binary import o32be as o32
+from ._deprecate import deprecate
+
+logger = logging.getLogger(__name__)
+
+is_cid = re.compile(rb"\w\w\w\w").match
+
+
+_MAGIC = b"\211PNG\r\n\032\n"
+
+
+_MODES = {
+ # supported bits/color combinations, and corresponding modes/rawmodes
+ # Greyscale
+ (1, 0): ("1", "1"),
+ (2, 0): ("L", "L;2"),
+ (4, 0): ("L", "L;4"),
+ (8, 0): ("L", "L"),
+ (16, 0): ("I", "I;16B"),
+ # Truecolour
+ (8, 2): ("RGB", "RGB"),
+ (16, 2): ("RGB", "RGB;16B"),
+ # Indexed-colour
+ (1, 3): ("P", "P;1"),
+ (2, 3): ("P", "P;2"),
+ (4, 3): ("P", "P;4"),
+ (8, 3): ("P", "P"),
+ # Greyscale with alpha
+ (8, 4): ("LA", "LA"),
+ (16, 4): ("RGBA", "LA;16B"), # LA;16B->LA not yet available
+ # Truecolour with alpha
+ (8, 6): ("RGBA", "RGBA"),
+ (16, 6): ("RGBA", "RGBA;16B"),
+}
+
+
+_simple_palette = re.compile(b"^\xff*\x00\xff*$")
+
+MAX_TEXT_CHUNK = ImageFile.SAFEBLOCK
+"""
+Maximum decompressed size for a iTXt or zTXt chunk.
+Eliminates decompression bombs where compressed chunks can expand 1000x.
+See :ref:`Text in PNG File Format<png-text>`.
+"""
+MAX_TEXT_MEMORY = 64 * MAX_TEXT_CHUNK
+"""
+Set the maximum total text chunk size.
+See :ref:`Text in PNG File Format<png-text>`.
+"""
+
+
+# APNG frame disposal modes
+class Disposal(IntEnum):
+ OP_NONE = 0
+ """
+ No disposal is done on this frame before rendering the next frame.
+ See :ref:`Saving APNG sequences<apng-saving>`.
+ """
+ OP_BACKGROUND = 1
+ """
+ This frame’s modified region is cleared to fully transparent black before rendering
+ the next frame.
+ See :ref:`Saving APNG sequences<apng-saving>`.
+ """
+ OP_PREVIOUS = 2
+ """
+ This frame’s modified region is reverted to the previous frame’s contents before
+ rendering the next frame.
+ See :ref:`Saving APNG sequences<apng-saving>`.
+ """
+
+
+# APNG frame blend modes
+class Blend(IntEnum):
+ OP_SOURCE = 0
+ """
+ All color components of this frame, including alpha, overwrite the previous output
+ image contents.
+ See :ref:`Saving APNG sequences<apng-saving>`.
+ """
+ OP_OVER = 1
+ """
+ This frame should be alpha composited with the previous output image contents.
+ See :ref:`Saving APNG sequences<apng-saving>`.
+ """
+
+
+def __getattr__(name):
+ for enum, prefix in {Disposal: "APNG_DISPOSE_", Blend: "APNG_BLEND_"}.items():
+ if name.startswith(prefix):
+ name = name[len(prefix) :]
+ if name in enum.__members__:
+ deprecate(f"{prefix}{name}", 10, f"{enum.__name__}.{name}")
+ return enum[name]
+ raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
+
+
+def _safe_zlib_decompress(s):
+ dobj = zlib.decompressobj()
+ plaintext = dobj.decompress(s, MAX_TEXT_CHUNK)
+ if dobj.unconsumed_tail:
+ raise ValueError("Decompressed Data Too Large")
+ return plaintext
+
+
+def _crc32(data, seed=0):
+ return zlib.crc32(data, seed) & 0xFFFFFFFF
+
+
+# --------------------------------------------------------------------
+# Support classes. Suitable for PNG and related formats like MNG etc.
+
+
+class ChunkStream:
+ def __init__(self, fp):
+
+ self.fp = fp
+ self.queue = []
+
+ def read(self):
+ """Fetch a new chunk. Returns header information."""
+ cid = None
+
+ if self.queue:
+ cid, pos, length = self.queue.pop()
+ self.fp.seek(pos)
+ else:
+ s = self.fp.read(8)
+ cid = s[4:]
+ pos = self.fp.tell()
+ length = i32(s)
+
+ if not is_cid(cid):
+ if not ImageFile.LOAD_TRUNCATED_IMAGES:
+ raise SyntaxError(f"broken PNG file (chunk {repr(cid)})")
+
+ return cid, pos, length
+
+ def __enter__(self):
+ return self
+
+ def __exit__(self, *args):
+ self.close()
+
+ def close(self):
+ self.queue = self.fp = None
+
+ def push(self, cid, pos, length):
+
+ self.queue.append((cid, pos, length))
+
+ def call(self, cid, pos, length):
+ """Call the appropriate chunk handler"""
+
+ logger.debug("STREAM %r %s %s", cid, pos, length)
+ return getattr(self, "chunk_" + cid.decode("ascii"))(pos, length)
+
+ def crc(self, cid, data):
+ """Read and verify checksum"""
+
+ # Skip CRC checks for ancillary chunks if allowed to load truncated
+ # images
+ # 5th byte of first char is 1 [specs, section 5.4]
+ if ImageFile.LOAD_TRUNCATED_IMAGES and (cid[0] >> 5 & 1):
+ self.crc_skip(cid, data)
+ return
+
+ try:
+ crc1 = _crc32(data, _crc32(cid))
+ crc2 = i32(self.fp.read(4))
+ if crc1 != crc2:
+ raise SyntaxError(
+ f"broken PNG file (bad header checksum in {repr(cid)})"
+ )
+ except struct.error as e:
+ raise SyntaxError(
+ f"broken PNG file (incomplete checksum in {repr(cid)})"
+ ) from e
+
+ def crc_skip(self, cid, data):
+ """Read checksum"""
+
+ self.fp.read(4)
+
+ def verify(self, endchunk=b"IEND"):
+
+ # Simple approach; just calculate checksum for all remaining
+ # blocks. Must be called directly after open.
+
+ cids = []
+
+ while True:
+ try:
+ cid, pos, length = self.read()
+ except struct.error as e:
+ raise OSError("truncated PNG file") from e
+
+ if cid == endchunk:
+ break
+ self.crc(cid, ImageFile._safe_read(self.fp, length))
+ cids.append(cid)
+
+ return cids
+
+
+class iTXt(str):
+ """
+ Subclass of string to allow iTXt chunks to look like strings while
+ keeping their extra information
+
+ """
+
+ @staticmethod
+ def __new__(cls, text, lang=None, tkey=None):
+ """
+ :param cls: the class to use when creating the instance
+ :param text: value for this key
+ :param lang: language code
+ :param tkey: UTF-8 version of the key name
+ """
+
+ self = str.__new__(cls, text)
+ self.lang = lang
+ self.tkey = tkey
+ return self
+
+
+class PngInfo:
+ """
+ PNG chunk container (for use with save(pnginfo=))
+
+ """
+
+ def __init__(self):
+ self.chunks = []
+
+ def add(self, cid, data, after_idat=False):
+ """Appends an arbitrary chunk. Use with caution.
+
+ :param cid: a byte string, 4 bytes long.
+ :param data: a byte string of the encoded data
+ :param after_idat: for use with private chunks. Whether the chunk
+ should be written after IDAT
+
+ """
+
+ chunk = [cid, data]
+ if after_idat:
+ chunk.append(True)
+ self.chunks.append(tuple(chunk))
+
+ def add_itxt(self, key, value, lang="", tkey="", zip=False):
+ """Appends an iTXt chunk.
+
+ :param key: latin-1 encodable text key name
+ :param value: value for this key
+ :param lang: language code
+ :param tkey: UTF-8 version of the key name
+ :param zip: compression flag
+
+ """
+
+ if not isinstance(key, bytes):
+ key = key.encode("latin-1", "strict")
+ if not isinstance(value, bytes):
+ value = value.encode("utf-8", "strict")
+ if not isinstance(lang, bytes):
+ lang = lang.encode("utf-8", "strict")
+ if not isinstance(tkey, bytes):
+ tkey = tkey.encode("utf-8", "strict")
+
+ if zip:
+ self.add(
+ b"iTXt",
+ key + b"\0\x01\0" + lang + b"\0" + tkey + b"\0" + zlib.compress(value),
+ )
+ else:
+ self.add(b"iTXt", key + b"\0\0\0" + lang + b"\0" + tkey + b"\0" + value)
+
+ def add_text(self, key, value, zip=False):
+ """Appends a text chunk.
+
+ :param key: latin-1 encodable text key name
+ :param value: value for this key, text or an
+ :py:class:`PIL.PngImagePlugin.iTXt` instance
+ :param zip: compression flag
+
+ """
+ if isinstance(value, iTXt):
+ return self.add_itxt(key, value, value.lang, value.tkey, zip=zip)
+
+ # The tEXt chunk stores latin-1 text
+ if not isinstance(value, bytes):
+ try:
+ value = value.encode("latin-1", "strict")
+ except UnicodeError:
+ return self.add_itxt(key, value, zip=zip)
+
+ if not isinstance(key, bytes):
+ key = key.encode("latin-1", "strict")
+
+ if zip:
+ self.add(b"zTXt", key + b"\0\0" + zlib.compress(value))
+ else:
+ self.add(b"tEXt", key + b"\0" + value)
+
+
+# --------------------------------------------------------------------
+# PNG image stream (IHDR/IEND)
+
+
+class PngStream(ChunkStream):
+ def __init__(self, fp):
+ super().__init__(fp)
+
+ # local copies of Image attributes
+ self.im_info = {}
+ self.im_text = {}
+ self.im_size = (0, 0)
+ self.im_mode = None
+ self.im_tile = None
+ self.im_palette = None
+ self.im_custom_mimetype = None
+ self.im_n_frames = None
+ self._seq_num = None
+ self.rewind_state = None
+
+ self.text_memory = 0
+
+ def check_text_memory(self, chunklen):
+ self.text_memory += chunklen
+ if self.text_memory > MAX_TEXT_MEMORY:
+ raise ValueError(
+ "Too much memory used in text chunks: "
+ f"{self.text_memory}>MAX_TEXT_MEMORY"
+ )
+
+ def save_rewind(self):
+ self.rewind_state = {
+ "info": self.im_info.copy(),
+ "tile": self.im_tile,
+ "seq_num": self._seq_num,
+ }
+
+ def rewind(self):
+ self.im_info = self.rewind_state["info"]
+ self.im_tile = self.rewind_state["tile"]
+ self._seq_num = self.rewind_state["seq_num"]
+
+ def chunk_iCCP(self, pos, length):
+
+ # ICC profile
+ s = ImageFile._safe_read(self.fp, length)
+ # according to PNG spec, the iCCP chunk contains:
+ # Profile name 1-79 bytes (character string)
+ # Null separator 1 byte (null character)
+ # Compression method 1 byte (0)
+ # Compressed profile n bytes (zlib with deflate compression)
+ i = s.find(b"\0")
+ logger.debug("iCCP profile name %r", s[:i])
+ logger.debug("Compression method %s", s[i])
+ comp_method = s[i]
+ if comp_method != 0:
+ raise SyntaxError(f"Unknown compression method {comp_method} in iCCP chunk")
+ try:
+ icc_profile = _safe_zlib_decompress(s[i + 2 :])
+ except ValueError:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ icc_profile = None
+ else:
+ raise
+ except zlib.error:
+ icc_profile = None # FIXME
+ self.im_info["icc_profile"] = icc_profile
+ return s
+
+ def chunk_IHDR(self, pos, length):
+
+ # image header
+ s = ImageFile._safe_read(self.fp, length)
+ if length < 13:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ return s
+ raise ValueError("Truncated IHDR chunk")
+ self.im_size = i32(s, 0), i32(s, 4)
+ try:
+ self.im_mode, self.im_rawmode = _MODES[(s[8], s[9])]
+ except Exception:
+ pass
+ if s[12]:
+ self.im_info["interlace"] = 1
+ if s[11]:
+ raise SyntaxError("unknown filter category")
+ return s
+
+ def chunk_IDAT(self, pos, length):
+
+ # image data
+ if "bbox" in self.im_info:
+ tile = [("zip", self.im_info["bbox"], pos, self.im_rawmode)]
+ else:
+ if self.im_n_frames is not None:
+ self.im_info["default_image"] = True
+ tile = [("zip", (0, 0) + self.im_size, pos, self.im_rawmode)]
+ self.im_tile = tile
+ self.im_idat = length
+ raise EOFError
+
+ def chunk_IEND(self, pos, length):
+
+ # end of PNG image
+ raise EOFError
+
+ def chunk_PLTE(self, pos, length):
+
+ # palette
+ s = ImageFile._safe_read(self.fp, length)
+ if self.im_mode == "P":
+ self.im_palette = "RGB", s
+ return s
+
+ def chunk_tRNS(self, pos, length):
+
+ # transparency
+ s = ImageFile._safe_read(self.fp, length)
+ if self.im_mode == "P":
+ if _simple_palette.match(s):
+ # tRNS contains only one full-transparent entry,
+ # other entries are full opaque
+ i = s.find(b"\0")
+ if i >= 0:
+ self.im_info["transparency"] = i
+ else:
+ # otherwise, we have a byte string with one alpha value
+ # for each palette entry
+ self.im_info["transparency"] = s
+ elif self.im_mode in ("1", "L", "I"):
+ self.im_info["transparency"] = i16(s)
+ elif self.im_mode == "RGB":
+ self.im_info["transparency"] = i16(s), i16(s, 2), i16(s, 4)
+ return s
+
+ def chunk_gAMA(self, pos, length):
+ # gamma setting
+ s = ImageFile._safe_read(self.fp, length)
+ self.im_info["gamma"] = i32(s) / 100000.0
+ return s
+
+ def chunk_cHRM(self, pos, length):
+ # chromaticity, 8 unsigned ints, actual value is scaled by 100,000
+ # WP x,y, Red x,y, Green x,y Blue x,y
+
+ s = ImageFile._safe_read(self.fp, length)
+ raw_vals = struct.unpack(">%dI" % (len(s) // 4), s)
+ self.im_info["chromaticity"] = tuple(elt / 100000.0 for elt in raw_vals)
+ return s
+
+ def chunk_sRGB(self, pos, length):
+ # srgb rendering intent, 1 byte
+ # 0 perceptual
+ # 1 relative colorimetric
+ # 2 saturation
+ # 3 absolute colorimetric
+
+ s = ImageFile._safe_read(self.fp, length)
+ if length < 1:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ return s
+ raise ValueError("Truncated sRGB chunk")
+ self.im_info["srgb"] = s[0]
+ return s
+
+ def chunk_pHYs(self, pos, length):
+
+ # pixels per unit
+ s = ImageFile._safe_read(self.fp, length)
+ if length < 9:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ return s
+ raise ValueError("Truncated pHYs chunk")
+ px, py = i32(s, 0), i32(s, 4)
+ unit = s[8]
+ if unit == 1: # meter
+ dpi = px * 0.0254, py * 0.0254
+ self.im_info["dpi"] = dpi
+ elif unit == 0:
+ self.im_info["aspect"] = px, py
+ return s
+
+ def chunk_tEXt(self, pos, length):
+
+ # text
+ s = ImageFile._safe_read(self.fp, length)
+ try:
+ k, v = s.split(b"\0", 1)
+ except ValueError:
+ # fallback for broken tEXt tags
+ k = s
+ v = b""
+ if k:
+ k = k.decode("latin-1", "strict")
+ v_str = v.decode("latin-1", "replace")
+
+ self.im_info[k] = v if k == "exif" else v_str
+ self.im_text[k] = v_str
+ self.check_text_memory(len(v_str))
+
+ return s
+
+ def chunk_zTXt(self, pos, length):
+
+ # compressed text
+ s = ImageFile._safe_read(self.fp, length)
+ try:
+ k, v = s.split(b"\0", 1)
+ except ValueError:
+ k = s
+ v = b""
+ if v:
+ comp_method = v[0]
+ else:
+ comp_method = 0
+ if comp_method != 0:
+ raise SyntaxError(f"Unknown compression method {comp_method} in zTXt chunk")
+ try:
+ v = _safe_zlib_decompress(v[1:])
+ except ValueError:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ v = b""
+ else:
+ raise
+ except zlib.error:
+ v = b""
+
+ if k:
+ k = k.decode("latin-1", "strict")
+ v = v.decode("latin-1", "replace")
+
+ self.im_info[k] = self.im_text[k] = v
+ self.check_text_memory(len(v))
+
+ return s
+
+ def chunk_iTXt(self, pos, length):
+
+ # international text
+ r = s = ImageFile._safe_read(self.fp, length)
+ try:
+ k, r = r.split(b"\0", 1)
+ except ValueError:
+ return s
+ if len(r) < 2:
+ return s
+ cf, cm, r = r[0], r[1], r[2:]
+ try:
+ lang, tk, v = r.split(b"\0", 2)
+ except ValueError:
+ return s
+ if cf != 0:
+ if cm == 0:
+ try:
+ v = _safe_zlib_decompress(v)
+ except ValueError:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ return s
+ else:
+ raise
+ except zlib.error:
+ return s
+ else:
+ return s
+ try:
+ k = k.decode("latin-1", "strict")
+ lang = lang.decode("utf-8", "strict")
+ tk = tk.decode("utf-8", "strict")
+ v = v.decode("utf-8", "strict")
+ except UnicodeError:
+ return s
+
+ self.im_info[k] = self.im_text[k] = iTXt(v, lang, tk)
+ self.check_text_memory(len(v))
+
+ return s
+
+ def chunk_eXIf(self, pos, length):
+ s = ImageFile._safe_read(self.fp, length)
+ self.im_info["exif"] = b"Exif\x00\x00" + s
+ return s
+
+ # APNG chunks
+ def chunk_acTL(self, pos, length):
+ s = ImageFile._safe_read(self.fp, length)
+ if length < 8:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ return s
+ raise ValueError("APNG contains truncated acTL chunk")
+ if self.im_n_frames is not None:
+ self.im_n_frames = None
+ warnings.warn("Invalid APNG, will use default PNG image if possible")
+ return s
+ n_frames = i32(s)
+ if n_frames == 0 or n_frames > 0x80000000:
+ warnings.warn("Invalid APNG, will use default PNG image if possible")
+ return s
+ self.im_n_frames = n_frames
+ self.im_info["loop"] = i32(s, 4)
+ self.im_custom_mimetype = "image/apng"
+ return s
+
+ def chunk_fcTL(self, pos, length):
+ s = ImageFile._safe_read(self.fp, length)
+ if length < 26:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ return s
+ raise ValueError("APNG contains truncated fcTL chunk")
+ seq = i32(s)
+ if (self._seq_num is None and seq != 0) or (
+ self._seq_num is not None and self._seq_num != seq - 1
+ ):
+ raise SyntaxError("APNG contains frame sequence errors")
+ self._seq_num = seq
+ width, height = i32(s, 4), i32(s, 8)
+ px, py = i32(s, 12), i32(s, 16)
+ im_w, im_h = self.im_size
+ if px + width > im_w or py + height > im_h:
+ raise SyntaxError("APNG contains invalid frames")
+ self.im_info["bbox"] = (px, py, px + width, py + height)
+ delay_num, delay_den = i16(s, 20), i16(s, 22)
+ if delay_den == 0:
+ delay_den = 100
+ self.im_info["duration"] = float(delay_num) / float(delay_den) * 1000
+ self.im_info["disposal"] = s[24]
+ self.im_info["blend"] = s[25]
+ return s
+
+ def chunk_fdAT(self, pos, length):
+ if length < 4:
+ if ImageFile.LOAD_TRUNCATED_IMAGES:
+ s = ImageFile._safe_read(self.fp, length)
+ return s
+ raise ValueError("APNG contains truncated fDAT chunk")
+ s = ImageFile._safe_read(self.fp, 4)
+ seq = i32(s)
+ if self._seq_num != seq - 1:
+ raise SyntaxError("APNG contains frame sequence errors")
+ self._seq_num = seq
+ return self.chunk_IDAT(pos + 4, length - 4)
+
+
+# --------------------------------------------------------------------
+# PNG reader
+
+
+def _accept(prefix):
+ return prefix[:8] == _MAGIC
+
+
+##
+# Image plugin for PNG images.
+
+
+class PngImageFile(ImageFile.ImageFile):
+
+ format = "PNG"
+ format_description = "Portable network graphics"
+
+ def _open(self):
+
+ if not _accept(self.fp.read(8)):
+ raise SyntaxError("not a PNG file")
+ self._fp = self.fp
+ self.__frame = 0
+
+ #
+ # Parse headers up to the first IDAT or fDAT chunk
+
+ self.private_chunks = []
+ self.png = PngStream(self.fp)
+
+ while True:
+
+ #
+ # get next chunk
+
+ cid, pos, length = self.png.read()
+
+ try:
+ s = self.png.call(cid, pos, length)
+ except EOFError:
+ break
+ except AttributeError:
+ logger.debug("%r %s %s (unknown)", cid, pos, length)
+ s = ImageFile._safe_read(self.fp, length)
+ if cid[1:2].islower():
+ self.private_chunks.append((cid, s))
+
+ self.png.crc(cid, s)
+
+ #
+ # Copy relevant attributes from the PngStream. An alternative
+ # would be to let the PngStream class modify these attributes
+ # directly, but that introduces circular references which are
+ # difficult to break if things go wrong in the decoder...
+ # (believe me, I've tried ;-)
+
+ self.mode = self.png.im_mode
+ self._size = self.png.im_size
+ self.info = self.png.im_info
+ self._text = None
+ self.tile = self.png.im_tile
+ self.custom_mimetype = self.png.im_custom_mimetype
+ self.n_frames = self.png.im_n_frames or 1
+ self.default_image = self.info.get("default_image", False)
+
+ if self.png.im_palette:
+ rawmode, data = self.png.im_palette
+ self.palette = ImagePalette.raw(rawmode, data)
+
+ if cid == b"fdAT":
+ self.__prepare_idat = length - 4
+ else:
+ self.__prepare_idat = length # used by load_prepare()
+
+ if self.png.im_n_frames is not None:
+ self._close_exclusive_fp_after_loading = False
+ self.png.save_rewind()
+ self.__rewind_idat = self.__prepare_idat
+ self.__rewind = self._fp.tell()
+ if self.default_image:
+ # IDAT chunk contains default image and not first animation frame
+ self.n_frames += 1
+ self._seek(0)
+ self.is_animated = self.n_frames > 1
+
+ @property
+ def text(self):
+ # experimental
+ if self._text is None:
+ # iTxt, tEXt and zTXt chunks may appear at the end of the file
+ # So load the file to ensure that they are read
+ if self.is_animated:
+ frame = self.__frame
+ # for APNG, seek to the final frame before loading
+ self.seek(self.n_frames - 1)
+ self.load()
+ if self.is_animated:
+ self.seek(frame)
+ return self._text
+
+ def verify(self):
+ """Verify PNG file"""
+
+ if self.fp is None:
+ raise RuntimeError("verify must be called directly after open")
+
+ # back up to beginning of IDAT block
+ self.fp.seek(self.tile[0][2] - 8)
+
+ self.png.verify()
+ self.png.close()
+
+ if self._exclusive_fp:
+ self.fp.close()
+ self.fp = None
+
+ def seek(self, frame):
+ if not self._seek_check(frame):
+ return
+ if frame < self.__frame:
+ self._seek(0, True)
+
+ last_frame = self.__frame
+ for f in range(self.__frame + 1, frame + 1):
+ try:
+ self._seek(f)
+ except EOFError as e:
+ self.seek(last_frame)
+ raise EOFError("no more images in APNG file") from e
+
+ def _seek(self, frame, rewind=False):
+ if frame == 0:
+ if rewind:
+ self._fp.seek(self.__rewind)
+ self.png.rewind()
+ self.__prepare_idat = self.__rewind_idat
+ self.im = None
+ if self.pyaccess:
+ self.pyaccess = None
+ self.info = self.png.im_info
+ self.tile = self.png.im_tile
+ self.fp = self._fp
+ self._prev_im = None
+ self.dispose = None
+ self.default_image = self.info.get("default_image", False)
+ self.dispose_op = self.info.get("disposal")
+ self.blend_op = self.info.get("blend")
+ self.dispose_extent = self.info.get("bbox")
+ self.__frame = 0
+ else:
+ if frame != self.__frame + 1:
+ raise ValueError(f"cannot seek to frame {frame}")
+
+ # ensure previous frame was loaded
+ self.load()
+
+ if self.dispose:
+ self.im.paste(self.dispose, self.dispose_extent)
+ self._prev_im = self.im.copy()
+
+ self.fp = self._fp
+
+ # advance to the next frame
+ if self.__prepare_idat:
+ ImageFile._safe_read(self.fp, self.__prepare_idat)
+ self.__prepare_idat = 0
+ frame_start = False
+ while True:
+ self.fp.read(4) # CRC
+
+ try:
+ cid, pos, length = self.png.read()
+ except (struct.error, SyntaxError):
+ break
+
+ if cid == b"IEND":
+ raise EOFError("No more images in APNG file")
+ if cid == b"fcTL":
+ if frame_start:
+ # there must be at least one fdAT chunk between fcTL chunks
+ raise SyntaxError("APNG missing frame data")
+ frame_start = True
+
+ try:
+ self.png.call(cid, pos, length)
+ except UnicodeDecodeError:
+ break
+ except EOFError:
+ if cid == b"fdAT":
+ length -= 4
+ if frame_start:
+ self.__prepare_idat = length
+ break
+ ImageFile._safe_read(self.fp, length)
+ except AttributeError:
+ logger.debug("%r %s %s (unknown)", cid, pos, length)
+ ImageFile._safe_read(self.fp, length)
+
+ self.__frame = frame
+ self.tile = self.png.im_tile
+ self.dispose_op = self.info.get("disposal")
+ self.blend_op = self.info.get("blend")
+ self.dispose_extent = self.info.get("bbox")
+
+ if not self.tile:
+ raise EOFError
+
+ # setup frame disposal (actual disposal done when needed in the next _seek())
+ if self._prev_im is None and self.dispose_op == Disposal.OP_PREVIOUS:
+ self.dispose_op = Disposal.OP_BACKGROUND
+
+ if self.dispose_op == Disposal.OP_PREVIOUS:
+ self.dispose = self._prev_im.copy()
+ self.dispose = self._crop(self.dispose, self.dispose_extent)
+ elif self.dispose_op == Disposal.OP_BACKGROUND:
+ self.dispose = Image.core.fill(self.mode, self.size)
+ self.dispose = self._crop(self.dispose, self.dispose_extent)
+ else:
+ self.dispose = None
+
+ def tell(self):
+ return self.__frame
+
+ def load_prepare(self):
+ """internal: prepare to read PNG file"""
+
+ if self.info.get("interlace"):
+ self.decoderconfig = self.decoderconfig + (1,)
+
+ self.__idat = self.__prepare_idat # used by load_read()
+ ImageFile.ImageFile.load_prepare(self)
+
+ def load_read(self, read_bytes):
+ """internal: read more image data"""
+
+ while self.__idat == 0:
+ # end of chunk, skip forward to next one
+
+ self.fp.read(4) # CRC
+
+ cid, pos, length = self.png.read()
+
+ if cid not in [b"IDAT", b"DDAT", b"fdAT"]:
+ self.png.push(cid, pos, length)
+ return b""
+
+ if cid == b"fdAT":
+ try:
+ self.png.call(cid, pos, length)
+ except EOFError:
+ pass
+ self.__idat = length - 4 # sequence_num has already been read
+ else:
+ self.__idat = length # empty chunks are allowed
+
+ # read more data from this chunk
+ if read_bytes <= 0:
+ read_bytes = self.__idat
+ else:
+ read_bytes = min(read_bytes, self.__idat)
+
+ self.__idat = self.__idat - read_bytes
+
+ return self.fp.read(read_bytes)
+
+ def load_end(self):
+ """internal: finished reading image data"""
+ if self.__idat != 0:
+ self.fp.read(self.__idat)
+ while True:
+ self.fp.read(4) # CRC
+
+ try:
+ cid, pos, length = self.png.read()
+ except (struct.error, SyntaxError):
+ break
+
+ if cid == b"IEND":
+ break
+ elif cid == b"fcTL" and self.is_animated:
+ # start of the next frame, stop reading
+ self.__prepare_idat = 0
+ self.png.push(cid, pos, length)
+ break
+
+ try:
+ self.png.call(cid, pos, length)
+ except UnicodeDecodeError:
+ break
+ except EOFError:
+ if cid == b"fdAT":
+ length -= 4
+ ImageFile._safe_read(self.fp, length)
+ except AttributeError:
+ logger.debug("%r %s %s (unknown)", cid, pos, length)
+ s = ImageFile._safe_read(self.fp, length)
+ if cid[1:2].islower():
+ self.private_chunks.append((cid, s, True))
+ self._text = self.png.im_text
+ if not self.is_animated:
+ self.png.close()
+ self.png = None
+ else:
+ if self._prev_im and self.blend_op == Blend.OP_OVER:
+ updated = self._crop(self.im, self.dispose_extent)
+ self._prev_im.paste(
+ updated, self.dispose_extent, updated.convert("RGBA")
+ )
+ self.im = self._prev_im
+ if self.pyaccess:
+ self.pyaccess = None
+
+ def _getexif(self):
+ if "exif" not in self.info:
+ self.load()
+ if "exif" not in self.info and "Raw profile type exif" not in self.info:
+ return None
+ return self.getexif()._get_merged_dict()
+
+ def getexif(self):
+ if "exif" not in self.info:
+ self.load()
+
+ return super().getexif()
+
+ def getxmp(self):
+ """
+ Returns a dictionary containing the XMP tags.
+ Requires defusedxml to be installed.
+
+ :returns: XMP tags in a dictionary.
+ """
+ return (
+ self._getxmp(self.info["XML:com.adobe.xmp"])
+ if "XML:com.adobe.xmp" in self.info
+ else {}
+ )
+
+
+# --------------------------------------------------------------------
+# PNG writer
+
+_OUTMODES = {
+ # supported PIL modes, and corresponding rawmodes/bits/color combinations
+ "1": ("1", b"\x01\x00"),
+ "L;1": ("L;1", b"\x01\x00"),
+ "L;2": ("L;2", b"\x02\x00"),
+ "L;4": ("L;4", b"\x04\x00"),
+ "L": ("L", b"\x08\x00"),
+ "LA": ("LA", b"\x08\x04"),
+ "I": ("I;16B", b"\x10\x00"),
+ "I;16": ("I;16B", b"\x10\x00"),
+ "P;1": ("P;1", b"\x01\x03"),
+ "P;2": ("P;2", b"\x02\x03"),
+ "P;4": ("P;4", b"\x04\x03"),
+ "P": ("P", b"\x08\x03"),
+ "RGB": ("RGB", b"\x08\x02"),
+ "RGBA": ("RGBA", b"\x08\x06"),
+}
+
+
+def putchunk(fp, cid, *data):
+ """Write a PNG chunk (including CRC field)"""
+
+ data = b"".join(data)
+
+ fp.write(o32(len(data)) + cid)
+ fp.write(data)
+ crc = _crc32(data, _crc32(cid))
+ fp.write(o32(crc))
+
+
+class _idat:
+ # wrap output from the encoder in IDAT chunks
+
+ def __init__(self, fp, chunk):
+ self.fp = fp
+ self.chunk = chunk
+
+ def write(self, data):
+ self.chunk(self.fp, b"IDAT", data)
+
+
+class _fdat:
+ # wrap encoder output in fdAT chunks
+
+ def __init__(self, fp, chunk, seq_num):
+ self.fp = fp
+ self.chunk = chunk
+ self.seq_num = seq_num
+
+ def write(self, data):
+ self.chunk(self.fp, b"fdAT", o32(self.seq_num), data)
+ self.seq_num += 1
+
+
+def _write_multiple_frames(im, fp, chunk, rawmode, default_image, append_images):
+ duration = im.encoderinfo.get("duration", im.info.get("duration", 0))
+ loop = im.encoderinfo.get("loop", im.info.get("loop", 0))
+ disposal = im.encoderinfo.get("disposal", im.info.get("disposal", Disposal.OP_NONE))
+ blend = im.encoderinfo.get("blend", im.info.get("blend", Blend.OP_SOURCE))
+
+ if default_image:
+ chain = itertools.chain(append_images)
+ else:
+ chain = itertools.chain([im], append_images)
+
+ im_frames = []
+ frame_count = 0
+ for im_seq in chain:
+ for im_frame in ImageSequence.Iterator(im_seq):
+ if im_frame.mode == rawmode:
+ im_frame = im_frame.copy()
+ else:
+ if rawmode == "P":
+ im_frame = im_frame.convert(rawmode, palette=im.palette)
+ else:
+ im_frame = im_frame.convert(rawmode)
+ encoderinfo = im.encoderinfo.copy()
+ if isinstance(duration, (list, tuple)):
+ encoderinfo["duration"] = duration[frame_count]
+ if isinstance(disposal, (list, tuple)):
+ encoderinfo["disposal"] = disposal[frame_count]
+ if isinstance(blend, (list, tuple)):
+ encoderinfo["blend"] = blend[frame_count]
+ frame_count += 1
+
+ if im_frames:
+ previous = im_frames[-1]
+ prev_disposal = previous["encoderinfo"].get("disposal")
+ prev_blend = previous["encoderinfo"].get("blend")
+ if prev_disposal == Disposal.OP_PREVIOUS and len(im_frames) < 2:
+ prev_disposal = Disposal.OP_BACKGROUND
+
+ if prev_disposal == Disposal.OP_BACKGROUND:
+ base_im = previous["im"].copy()
+ dispose = Image.core.fill("RGBA", im.size, (0, 0, 0, 0))
+ bbox = previous["bbox"]
+ if bbox:
+ dispose = dispose.crop(bbox)
+ else:
+ bbox = (0, 0) + im.size
+ base_im.paste(dispose, bbox)
+ elif prev_disposal == Disposal.OP_PREVIOUS:
+ base_im = im_frames[-2]["im"]
+ else:
+ base_im = previous["im"]
+ delta = ImageChops.subtract_modulo(
+ im_frame.convert("RGB"), base_im.convert("RGB")
+ )
+ bbox = delta.getbbox()
+ if (
+ not bbox
+ and prev_disposal == encoderinfo.get("disposal")
+ and prev_blend == encoderinfo.get("blend")
+ ):
+ if isinstance(duration, (list, tuple)):
+ previous["encoderinfo"]["duration"] += encoderinfo["duration"]
+ continue
+ else:
+ bbox = None
+ im_frames.append({"im": im_frame, "bbox": bbox, "encoderinfo": encoderinfo})
+
+ # animation control
+ chunk(
+ fp,
+ b"acTL",
+ o32(len(im_frames)), # 0: num_frames
+ o32(loop), # 4: num_plays
+ )
+
+ # default image IDAT (if it exists)
+ if default_image:
+ ImageFile._save(im, _idat(fp, chunk), [("zip", (0, 0) + im.size, 0, rawmode)])
+
+ seq_num = 0
+ for frame, frame_data in enumerate(im_frames):
+ im_frame = frame_data["im"]
+ if not frame_data["bbox"]:
+ bbox = (0, 0) + im_frame.size
+ else:
+ bbox = frame_data["bbox"]
+ im_frame = im_frame.crop(bbox)
+ size = im_frame.size
+ encoderinfo = frame_data["encoderinfo"]
+ frame_duration = int(round(encoderinfo.get("duration", duration)))
+ frame_disposal = encoderinfo.get("disposal", disposal)
+ frame_blend = encoderinfo.get("blend", blend)
+ # frame control
+ chunk(
+ fp,
+ b"fcTL",
+ o32(seq_num), # sequence_number
+ o32(size[0]), # width
+ o32(size[1]), # height
+ o32(bbox[0]), # x_offset
+ o32(bbox[1]), # y_offset
+ o16(frame_duration), # delay_numerator
+ o16(1000), # delay_denominator
+ o8(frame_disposal), # dispose_op
+ o8(frame_blend), # blend_op
+ )
+ seq_num += 1
+ # frame data
+ if frame == 0 and not default_image:
+ # first frame must be in IDAT chunks for backwards compatibility
+ ImageFile._save(
+ im_frame,
+ _idat(fp, chunk),
+ [("zip", (0, 0) + im_frame.size, 0, rawmode)],
+ )
+ else:
+ fdat_chunks = _fdat(fp, chunk, seq_num)
+ ImageFile._save(
+ im_frame,
+ fdat_chunks,
+ [("zip", (0, 0) + im_frame.size, 0, rawmode)],
+ )
+ seq_num = fdat_chunks.seq_num
+
+
+def _save_all(im, fp, filename):
+ _save(im, fp, filename, save_all=True)
+
+
+def _save(im, fp, filename, chunk=putchunk, save_all=False):
+ # save an image to disk (called by the save method)
+
+ if save_all:
+ default_image = im.encoderinfo.get(
+ "default_image", im.info.get("default_image")
+ )
+ modes = set()
+ append_images = im.encoderinfo.get("append_images", [])
+ if default_image:
+ chain = itertools.chain(append_images)
+ else:
+ chain = itertools.chain([im], append_images)
+ for im_seq in chain:
+ for im_frame in ImageSequence.Iterator(im_seq):
+ modes.add(im_frame.mode)
+ for mode in ("RGBA", "RGB", "P"):
+ if mode in modes:
+ break
+ else:
+ mode = modes.pop()
+ else:
+ mode = im.mode
+
+ if mode == "P":
+
+ #
+ # attempt to minimize storage requirements for palette images
+ if "bits" in im.encoderinfo:
+ # number of bits specified by user
+ colors = min(1 << im.encoderinfo["bits"], 256)
+ else:
+ # check palette contents
+ if im.palette:
+ colors = max(min(len(im.palette.getdata()[1]) // 3, 256), 1)
+ else:
+ colors = 256
+
+ if colors <= 16:
+ if colors <= 2:
+ bits = 1
+ elif colors <= 4:
+ bits = 2
+ else:
+ bits = 4
+ mode = f"{mode};{bits}"
+
+ # encoder options
+ im.encoderconfig = (
+ im.encoderinfo.get("optimize", False),
+ im.encoderinfo.get("compress_level", -1),
+ im.encoderinfo.get("compress_type", -1),
+ im.encoderinfo.get("dictionary", b""),
+ )
+
+ # get the corresponding PNG mode
+ try:
+ rawmode, mode = _OUTMODES[mode]
+ except KeyError as e:
+ raise OSError(f"cannot write mode {mode} as PNG") from e
+
+ #
+ # write minimal PNG file
+
+ fp.write(_MAGIC)
+
+ chunk(
+ fp,
+ b"IHDR",
+ o32(im.size[0]), # 0: size
+ o32(im.size[1]),
+ mode, # 8: depth/type
+ b"\0", # 10: compression
+ b"\0", # 11: filter category
+ b"\0", # 12: interlace flag
+ )
+
+ chunks = [b"cHRM", b"gAMA", b"sBIT", b"sRGB", b"tIME"]
+
+ icc = im.encoderinfo.get("icc_profile", im.info.get("icc_profile"))
+ if icc:
+ # ICC profile
+ # according to PNG spec, the iCCP chunk contains:
+ # Profile name 1-79 bytes (character string)
+ # Null separator 1 byte (null character)
+ # Compression method 1 byte (0)
+ # Compressed profile n bytes (zlib with deflate compression)
+ name = b"ICC Profile"
+ data = name + b"\0\0" + zlib.compress(icc)
+ chunk(fp, b"iCCP", data)
+
+ # You must either have sRGB or iCCP.
+ # Disallow sRGB chunks when an iCCP-chunk has been emitted.
+ chunks.remove(b"sRGB")
+
+ info = im.encoderinfo.get("pnginfo")
+ if info:
+ chunks_multiple_allowed = [b"sPLT", b"iTXt", b"tEXt", b"zTXt"]
+ for info_chunk in info.chunks:
+ cid, data = info_chunk[:2]
+ if cid in chunks:
+ chunks.remove(cid)
+ chunk(fp, cid, data)
+ elif cid in chunks_multiple_allowed:
+ chunk(fp, cid, data)
+ elif cid[1:2].islower():
+ # Private chunk
+ after_idat = info_chunk[2:3]
+ if not after_idat:
+ chunk(fp, cid, data)
+
+ if im.mode == "P":
+ palette_byte_number = colors * 3
+ palette_bytes = im.im.getpalette("RGB")[:palette_byte_number]
+ while len(palette_bytes) < palette_byte_number:
+ palette_bytes += b"\0"
+ chunk(fp, b"PLTE", palette_bytes)
+
+ transparency = im.encoderinfo.get("transparency", im.info.get("transparency", None))
+
+ if transparency or transparency == 0:
+ if im.mode == "P":
+ # limit to actual palette size
+ alpha_bytes = colors
+ if isinstance(transparency, bytes):
+ chunk(fp, b"tRNS", transparency[:alpha_bytes])
+ else:
+ transparency = max(0, min(255, transparency))
+ alpha = b"\xFF" * transparency + b"\0"
+ chunk(fp, b"tRNS", alpha[:alpha_bytes])
+ elif im.mode in ("1", "L", "I"):
+ transparency = max(0, min(65535, transparency))
+ chunk(fp, b"tRNS", o16(transparency))
+ elif im.mode == "RGB":
+ red, green, blue = transparency
+ chunk(fp, b"tRNS", o16(red) + o16(green) + o16(blue))
+ else:
+ if "transparency" in im.encoderinfo:
+ # don't bother with transparency if it's an RGBA
+ # and it's in the info dict. It's probably just stale.
+ raise OSError("cannot use transparency for this mode")
+ else:
+ if im.mode == "P" and im.im.getpalettemode() == "RGBA":
+ alpha = im.im.getpalette("RGBA", "A")
+ alpha_bytes = colors
+ chunk(fp, b"tRNS", alpha[:alpha_bytes])
+
+ dpi = im.encoderinfo.get("dpi")
+ if dpi:
+ chunk(
+ fp,
+ b"pHYs",
+ o32(int(dpi[0] / 0.0254 + 0.5)),
+ o32(int(dpi[1] / 0.0254 + 0.5)),
+ b"\x01",
+ )
+
+ if info:
+ chunks = [b"bKGD", b"hIST"]
+ for info_chunk in info.chunks:
+ cid, data = info_chunk[:2]
+ if cid in chunks:
+ chunks.remove(cid)
+ chunk(fp, cid, data)
+
+ exif = im.encoderinfo.get("exif", im.info.get("exif"))
+ if exif:
+ if isinstance(exif, Image.Exif):
+ exif = exif.tobytes(8)
+ if exif.startswith(b"Exif\x00\x00"):
+ exif = exif[6:]
+ chunk(fp, b"eXIf", exif)
+
+ if save_all:
+ _write_multiple_frames(im, fp, chunk, rawmode, default_image, append_images)
+ else:
+ ImageFile._save(im, _idat(fp, chunk), [("zip", (0, 0) + im.size, 0, rawmode)])
+
+ if info:
+ for info_chunk in info.chunks:
+ cid, data = info_chunk[:2]
+ if cid[1:2].islower():
+ # Private chunk
+ after_idat = info_chunk[2:3]
+ if after_idat:
+ chunk(fp, cid, data)
+
+ chunk(fp, b"IEND", b"")
+
+ if hasattr(fp, "flush"):
+ fp.flush()
+
+
+# --------------------------------------------------------------------
+# PNG chunk converter
+
+
+def getchunks(im, **params):
+ """Return a list of PNG chunks representing this image."""
+
+ class collector:
+ data = []
+
+ def write(self, data):
+ pass
+
+ def append(self, chunk):
+ self.data.append(chunk)
+
+ def append(fp, cid, *data):
+ data = b"".join(data)
+ crc = o32(_crc32(data, _crc32(cid)))
+ fp.append((cid, data, crc))
+
+ fp = collector()
+
+ try:
+ im.encoderinfo = params
+ _save(im, fp, None, append)
+ finally:
+ del im.encoderinfo
+
+ return fp.data
+
+
+# --------------------------------------------------------------------
+# Registry
+
+Image.register_open(PngImageFile.format, PngImageFile, _accept)
+Image.register_save(PngImageFile.format, _save)
+Image.register_save_all(PngImageFile.format, _save_all)
+
+Image.register_extensions(PngImageFile.format, [".png", ".apng"])
+
+Image.register_mime(PngImageFile.format, "image/png")