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1350 lines
41 KiB
Python
1350 lines
41 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# PNG support code
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#
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# See "PNG (Portable Network Graphics) Specification, version 1.0;
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# W3C Recommendation", 1996-10-01, Thomas Boutell (ed.).
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#
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# history:
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# 1996-05-06 fl Created (couldn't resist it)
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# 1996-12-14 fl Upgraded, added read and verify support (0.2)
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# 1996-12-15 fl Separate PNG stream parser
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# 1996-12-29 fl Added write support, added getchunks
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# 1996-12-30 fl Eliminated circular references in decoder (0.3)
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# 1998-07-12 fl Read/write 16-bit images as mode I (0.4)
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# 2001-02-08 fl Added transparency support (from Zircon) (0.5)
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# 2001-04-16 fl Don't close data source in "open" method (0.6)
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# 2004-02-24 fl Don't even pretend to support interlaced files (0.7)
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# 2004-08-31 fl Do basic sanity check on chunk identifiers (0.8)
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# 2004-09-20 fl Added PngInfo chunk container
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# 2004-12-18 fl Added DPI read support (based on code by Niki Spahiev)
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# 2008-08-13 fl Added tRNS support for RGB images
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# 2009-03-06 fl Support for preserving ICC profiles (by Florian Hoech)
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# 2009-03-08 fl Added zTXT support (from Lowell Alleman)
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# 2009-03-29 fl Read interlaced PNG files (from Conrado Porto Lopes Gouvua)
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#
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# Copyright (c) 1997-2009 by Secret Labs AB
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# Copyright (c) 1996 by Fredrik Lundh
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#
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# See the README file for information on usage and redistribution.
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#
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import itertools
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import logging
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import re
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import struct
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import warnings
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import zlib
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from . import Image, ImageChops, ImageFile, ImagePalette, ImageSequence
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from ._binary import i8, i16be as i16, i32be as i32, o8, o16be as o16, o32be as o32
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logger = logging.getLogger(__name__)
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is_cid = re.compile(br"\w\w\w\w").match
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_MAGIC = b"\211PNG\r\n\032\n"
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_MODES = {
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# supported bits/color combinations, and corresponding modes/rawmodes
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# Greyscale
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(1, 0): ("1", "1"),
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(2, 0): ("L", "L;2"),
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(4, 0): ("L", "L;4"),
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(8, 0): ("L", "L"),
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(16, 0): ("I", "I;16B"),
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# Truecolour
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(8, 2): ("RGB", "RGB"),
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(16, 2): ("RGB", "RGB;16B"),
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# Indexed-colour
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(1, 3): ("P", "P;1"),
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(2, 3): ("P", "P;2"),
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(4, 3): ("P", "P;4"),
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(8, 3): ("P", "P"),
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# Greyscale with alpha
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(8, 4): ("LA", "LA"),
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(16, 4): ("RGBA", "LA;16B"), # LA;16B->LA not yet available
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# Truecolour with alpha
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(8, 6): ("RGBA", "RGBA"),
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(16, 6): ("RGBA", "RGBA;16B"),
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}
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_simple_palette = re.compile(b"^\xff*\x00\xff*$")
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# Maximum decompressed size for a iTXt or zTXt chunk.
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# Eliminates decompression bombs where compressed chunks can expand 1000x
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MAX_TEXT_CHUNK = ImageFile.SAFEBLOCK
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# Set the maximum total text chunk size.
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MAX_TEXT_MEMORY = 64 * MAX_TEXT_CHUNK
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# APNG frame disposal modes
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APNG_DISPOSE_OP_NONE = 0
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APNG_DISPOSE_OP_BACKGROUND = 1
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APNG_DISPOSE_OP_PREVIOUS = 2
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# APNG frame blend modes
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APNG_BLEND_OP_SOURCE = 0
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APNG_BLEND_OP_OVER = 1
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def _safe_zlib_decompress(s):
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dobj = zlib.decompressobj()
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plaintext = dobj.decompress(s, MAX_TEXT_CHUNK)
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if dobj.unconsumed_tail:
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raise ValueError("Decompressed Data Too Large")
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return plaintext
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def _crc32(data, seed=0):
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return zlib.crc32(data, seed) & 0xFFFFFFFF
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# --------------------------------------------------------------------
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# Support classes. Suitable for PNG and related formats like MNG etc.
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class ChunkStream:
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def __init__(self, fp):
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self.fp = fp
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self.queue = []
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def read(self):
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"""Fetch a new chunk. Returns header information."""
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cid = None
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if self.queue:
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cid, pos, length = self.queue.pop()
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self.fp.seek(pos)
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else:
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s = self.fp.read(8)
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cid = s[4:]
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pos = self.fp.tell()
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length = i32(s)
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if not is_cid(cid):
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if not ImageFile.LOAD_TRUNCATED_IMAGES:
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raise SyntaxError("broken PNG file (chunk %s)" % repr(cid))
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return cid, pos, length
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def __enter__(self):
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return self
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def __exit__(self, *args):
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self.close()
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def close(self):
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self.queue = self.crc = self.fp = None
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def push(self, cid, pos, length):
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self.queue.append((cid, pos, length))
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def call(self, cid, pos, length):
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"""Call the appropriate chunk handler"""
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logger.debug("STREAM %r %s %s", cid, pos, length)
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return getattr(self, "chunk_" + cid.decode("ascii"))(pos, length)
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def crc(self, cid, data):
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"""Read and verify checksum"""
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# Skip CRC checks for ancillary chunks if allowed to load truncated
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# images
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# 5th byte of first char is 1 [specs, section 5.4]
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if ImageFile.LOAD_TRUNCATED_IMAGES and (i8(cid[0]) >> 5 & 1):
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self.crc_skip(cid, data)
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return
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try:
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crc1 = _crc32(data, _crc32(cid))
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crc2 = i32(self.fp.read(4))
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if crc1 != crc2:
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raise SyntaxError("broken PNG file (bad header checksum in %r)" % cid)
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except struct.error:
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raise SyntaxError("broken PNG file (incomplete checksum in %r)" % cid)
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def crc_skip(self, cid, data):
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"""Read checksum. Used if the C module is not present"""
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self.fp.read(4)
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def verify(self, endchunk=b"IEND"):
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# Simple approach; just calculate checksum for all remaining
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# blocks. Must be called directly after open.
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cids = []
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while True:
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try:
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cid, pos, length = self.read()
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except struct.error:
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raise OSError("truncated PNG file")
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if cid == endchunk:
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break
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self.crc(cid, ImageFile._safe_read(self.fp, length))
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cids.append(cid)
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return cids
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class iTXt(str):
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"""
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Subclass of string to allow iTXt chunks to look like strings while
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keeping their extra information
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"""
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@staticmethod
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def __new__(cls, text, lang=None, tkey=None):
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"""
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:param cls: the class to use when creating the instance
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:param text: value for this key
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:param lang: language code
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:param tkey: UTF-8 version of the key name
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"""
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self = str.__new__(cls, text)
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self.lang = lang
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self.tkey = tkey
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return self
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class PngInfo:
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"""
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PNG chunk container (for use with save(pnginfo=))
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"""
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def __init__(self):
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self.chunks = []
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def add(self, cid, data):
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"""Appends an arbitrary chunk. Use with caution.
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:param cid: a byte string, 4 bytes long.
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:param data: a byte string of the encoded data
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"""
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self.chunks.append((cid, data))
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def add_itxt(self, key, value, lang="", tkey="", zip=False):
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"""Appends an iTXt chunk.
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:param key: latin-1 encodable text key name
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:param value: value for this key
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:param lang: language code
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:param tkey: UTF-8 version of the key name
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:param zip: compression flag
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"""
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if not isinstance(key, bytes):
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key = key.encode("latin-1", "strict")
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if not isinstance(value, bytes):
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value = value.encode("utf-8", "strict")
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if not isinstance(lang, bytes):
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lang = lang.encode("utf-8", "strict")
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if not isinstance(tkey, bytes):
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tkey = tkey.encode("utf-8", "strict")
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if zip:
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self.add(
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b"iTXt",
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key + b"\0\x01\0" + lang + b"\0" + tkey + b"\0" + zlib.compress(value),
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)
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else:
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self.add(b"iTXt", key + b"\0\0\0" + lang + b"\0" + tkey + b"\0" + value)
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def add_text(self, key, value, zip=False):
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"""Appends a text chunk.
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:param key: latin-1 encodable text key name
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:param value: value for this key, text or an
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:py:class:`PIL.PngImagePlugin.iTXt` instance
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:param zip: compression flag
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"""
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if isinstance(value, iTXt):
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return self.add_itxt(key, value, value.lang, value.tkey, zip=zip)
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# The tEXt chunk stores latin-1 text
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if not isinstance(value, bytes):
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try:
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value = value.encode("latin-1", "strict")
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except UnicodeError:
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return self.add_itxt(key, value, zip=zip)
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if not isinstance(key, bytes):
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key = key.encode("latin-1", "strict")
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if zip:
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self.add(b"zTXt", key + b"\0\0" + zlib.compress(value))
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else:
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self.add(b"tEXt", key + b"\0" + value)
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# --------------------------------------------------------------------
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# PNG image stream (IHDR/IEND)
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class PngStream(ChunkStream):
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def __init__(self, fp):
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super().__init__(fp)
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# local copies of Image attributes
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self.im_info = {}
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self.im_text = {}
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self.im_size = (0, 0)
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self.im_mode = None
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self.im_tile = None
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self.im_palette = None
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self.im_custom_mimetype = None
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self.im_n_frames = None
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self._seq_num = None
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self.rewind_state = None
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self.text_memory = 0
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def check_text_memory(self, chunklen):
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self.text_memory += chunklen
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if self.text_memory > MAX_TEXT_MEMORY:
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raise ValueError(
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"Too much memory used in text chunks: %s>MAX_TEXT_MEMORY"
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% self.text_memory
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)
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def save_rewind(self):
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self.rewind_state = {
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"info": self.im_info.copy(),
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"tile": self.im_tile,
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"seq_num": self._seq_num,
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}
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def rewind(self):
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self.im_info = self.rewind_state["info"]
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self.im_tile = self.rewind_state["tile"]
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self._seq_num = self.rewind_state["seq_num"]
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def chunk_iCCP(self, pos, length):
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# ICC profile
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s = ImageFile._safe_read(self.fp, length)
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# according to PNG spec, the iCCP chunk contains:
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# Profile name 1-79 bytes (character string)
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# Null separator 1 byte (null character)
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# Compression method 1 byte (0)
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# Compressed profile n bytes (zlib with deflate compression)
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i = s.find(b"\0")
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logger.debug("iCCP profile name %r", s[:i])
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logger.debug("Compression method %s", i8(s[i]))
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comp_method = i8(s[i])
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if comp_method != 0:
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raise SyntaxError(
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"Unknown compression method %s in iCCP chunk" % comp_method
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)
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try:
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icc_profile = _safe_zlib_decompress(s[i + 2 :])
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except ValueError:
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if ImageFile.LOAD_TRUNCATED_IMAGES:
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icc_profile = None
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else:
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raise
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except zlib.error:
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icc_profile = None # FIXME
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self.im_info["icc_profile"] = icc_profile
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return s
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def chunk_IHDR(self, pos, length):
|
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# image header
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s = ImageFile._safe_read(self.fp, length)
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self.im_size = i32(s), i32(s[4:])
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try:
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self.im_mode, self.im_rawmode = _MODES[(i8(s[8]), i8(s[9]))]
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except Exception:
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pass
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if i8(s[12]):
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self.im_info["interlace"] = 1
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if i8(s[11]):
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raise SyntaxError("unknown filter category")
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return s
|
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def chunk_IDAT(self, pos, length):
|
|
|
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# image data
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if "bbox" in self.im_info:
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tile = [("zip", self.im_info["bbox"], pos, self.im_rawmode)]
|
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else:
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if self.im_n_frames is not None:
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self.im_info["default_image"] = True
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tile = [("zip", (0, 0) + self.im_size, pos, self.im_rawmode)]
|
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self.im_tile = tile
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self.im_idat = length
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raise EOFError
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def chunk_IEND(self, pos, length):
|
|
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# end of PNG image
|
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raise EOFError
|
|
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def chunk_PLTE(self, pos, length):
|
|
|
|
# palette
|
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s = ImageFile._safe_read(self.fp, length)
|
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if self.im_mode == "P":
|
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self.im_palette = "RGB", s
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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
|
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i = s.find(b"\0")
|
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if i >= 0:
|
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self.im_info["transparency"] = i
|
|
else:
|
|
# otherwise, we have a byte string with one alpha value
|
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# for each palette entry
|
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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)
|
|
self.im_info["srgb"] = i8(s)
|
|
return s
|
|
|
|
def chunk_pHYs(self, pos, length):
|
|
|
|
# pixels per unit
|
|
s = ImageFile._safe_read(self.fp, length)
|
|
px, py = i32(s), i32(s[4:])
|
|
unit = i8(s[8])
|
|
if unit == 1: # meter
|
|
dpi = int(px * 0.0254 + 0.5), int(py * 0.0254 + 0.5)
|
|
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 = v.decode("latin-1", "replace")
|
|
|
|
self.im_info[k] = self.im_text[k] = v
|
|
self.check_text_memory(len(v))
|
|
|
|
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 = i8(v[0])
|
|
else:
|
|
comp_method = 0
|
|
if comp_method != 0:
|
|
raise SyntaxError(
|
|
"Unknown compression method %s in zTXt chunk" % comp_method
|
|
)
|
|
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 = i8(r[0]), i8(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 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)
|
|
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"] = i8(s[24])
|
|
self.im_info["blend"] = i8(s[25])
|
|
return s
|
|
|
|
def chunk_fdAT(self, pos, length):
|
|
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 self.fp.read(8) != _MAGIC:
|
|
raise SyntaxError("not a PNG file")
|
|
self.__fp = self.fp
|
|
self.__frame = 0
|
|
|
|
#
|
|
# Parse headers up to the first IDAT or fDAT chunk
|
|
|
|
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)
|
|
|
|
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
|
|
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._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)
|
|
|
|
@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
|
|
|
|
@property
|
|
def n_frames(self):
|
|
if self._n_frames is None:
|
|
return 1
|
|
return self._n_frames
|
|
|
|
@property
|
|
def is_animated(self):
|
|
return self._n_frames is not None and self._n_frames > 1
|
|
|
|
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:
|
|
self.seek(last_frame)
|
|
raise EOFError("no more images in APNG file")
|
|
|
|
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
|
|
return
|
|
else:
|
|
if frame != self.__frame + 1:
|
|
raise ValueError("cannot seek to frame %d" % frame)
|
|
|
|
# ensure previous frame was loaded
|
|
self.load()
|
|
|
|
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
|
|
|
|
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"""
|
|
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)
|
|
ImageFile._safe_read(self.fp, length)
|
|
self._text = self.png.im_text
|
|
if not self.is_animated:
|
|
self.png.close()
|
|
self.png = None
|
|
else:
|
|
# setup frame disposal (actual disposal done when needed in _seek())
|
|
if self._prev_im is None and self.dispose_op == APNG_DISPOSE_OP_PREVIOUS:
|
|
self.dispose_op = APNG_DISPOSE_OP_BACKGROUND
|
|
|
|
if self.dispose_op == APNG_DISPOSE_OP_PREVIOUS:
|
|
dispose = self._prev_im.copy()
|
|
dispose = self._crop(dispose, self.dispose_extent)
|
|
elif self.dispose_op == APNG_DISPOSE_OP_BACKGROUND:
|
|
dispose = Image.core.fill("RGBA", self.size, (0, 0, 0, 0))
|
|
dispose = self._crop(dispose, self.dispose_extent)
|
|
else:
|
|
dispose = None
|
|
|
|
if self._prev_im and self.blend_op == APNG_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
|
|
self._prev_im = self.im.copy()
|
|
|
|
if dispose:
|
|
self._prev_im.paste(dispose, self.dispose_extent)
|
|
|
|
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 dict(self.getexif())
|
|
|
|
def getexif(self):
|
|
if "exif" not in self.info:
|
|
self.load()
|
|
|
|
if self._exif is None:
|
|
self._exif = Image.Exif()
|
|
|
|
exif_info = self.info.get("exif")
|
|
if exif_info is None and "Raw profile type exif" in self.info:
|
|
exif_info = bytes.fromhex(
|
|
"".join(self.info["Raw profile type exif"].split("\n")[3:])
|
|
)
|
|
self._exif.load(exif_info)
|
|
return self._exif
|
|
|
|
def _close__fp(self):
|
|
try:
|
|
if self.__fp != self.fp:
|
|
self.__fp.close()
|
|
except AttributeError:
|
|
pass
|
|
finally:
|
|
self.__fp = None
|
|
|
|
|
|
# --------------------------------------------------------------------
|
|
# 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 = im.encoderinfo.get("default_image", im.info.get("default_image"))
|
|
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"))
|
|
blend = im.encoderinfo.get("blend", im.info.get("blend"))
|
|
|
|
if default_image:
|
|
chain = itertools.chain(im.encoderinfo.get("append_images", []))
|
|
else:
|
|
chain = itertools.chain([im], im.encoderinfo.get("append_images", []))
|
|
|
|
im_frames = []
|
|
frame_count = 0
|
|
for im_seq in chain:
|
|
for im_frame in ImageSequence.Iterator(im_seq):
|
|
im_frame = im_frame.copy()
|
|
if im_frame.mode != im.mode:
|
|
if im.mode == "P":
|
|
im_frame = im_frame.convert(im.mode, palette=im.palette)
|
|
else:
|
|
im_frame = im_frame.convert(im.mode)
|
|
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 == APNG_DISPOSE_OP_PREVIOUS and len(im_frames) < 2:
|
|
prev_disposal == APNG_DISPOSE_OP_BACKGROUND
|
|
|
|
if prev_disposal == APNG_DISPOSE_OP_BACKGROUND:
|
|
base_im = previous["im"]
|
|
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 == APNG_DISPOSE_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")
|
|
):
|
|
duration = encoderinfo.get("duration", 0)
|
|
if duration:
|
|
if "duration" in previous["encoderinfo"]:
|
|
previous["encoderinfo"]["duration"] += duration
|
|
else:
|
|
previous["encoderinfo"]["duration"] = 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)), o32(loop), # 0: num_frames # 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
|
|
duration = int(round(frame_data["encoderinfo"].get("duration", 0)))
|
|
disposal = frame_data["encoderinfo"].get("disposal", APNG_DISPOSE_OP_NONE)
|
|
blend = frame_data["encoderinfo"].get("blend", APNG_BLEND_OP_SOURCE)
|
|
# 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(duration), # delay_numerator
|
|
o16(1000), # delay_denominator
|
|
o8(disposal), # dispose_op
|
|
o8(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)
|
|
|
|
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 = 1 << im.encoderinfo["bits"]
|
|
else:
|
|
# check palette contents
|
|
if im.palette:
|
|
colors = max(min(len(im.palette.getdata()[1]) // 3, 256), 2)
|
|
else:
|
|
colors = 256
|
|
|
|
if colors <= 2:
|
|
bits = 1
|
|
elif colors <= 4:
|
|
bits = 2
|
|
elif colors <= 16:
|
|
bits = 4
|
|
else:
|
|
bits = 8
|
|
if bits != 8:
|
|
mode = "%s;%d" % (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:
|
|
raise OSError("cannot write mode %s as PNG" % mode)
|
|
|
|
#
|
|
# 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 cid, data in info.chunks:
|
|
if cid in chunks:
|
|
chunks.remove(cid)
|
|
chunk(fp, cid, data)
|
|
elif cid in chunks_multiple_allowed:
|
|
chunk(fp, cid, data)
|
|
|
|
if im.mode == "P":
|
|
palette_byte_number = (2 ** bits) * 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 = 2 ** bits
|
|
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 = 2 ** bits
|
|
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 cid, data in info.chunks:
|
|
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)
|
|
else:
|
|
ImageFile._save(im, _idat(fp, chunk), [("zip", (0, 0) + im.size, 0, rawmode)])
|
|
|
|
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")
|