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https://github.com/python-pillow/Pillow.git
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Add APNG support
See #3483 Adds support for reading APNG files and seeking through frames, and adds basic support for writing APNG files.
This commit is contained in:
Peter Rowlands
Andrew Murray
parent
dab94e69d1
commit
67e3ccffeb
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@ -31,13 +31,15 @@
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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, ImageFile, ImagePalette
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from ._binary import i8, i16be as i16, i32be as i32, o16be as o16, o32be as o32
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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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@ -81,6 +83,16 @@ MAX_TEXT_CHUNK = ImageFile.SAFEBLOCK
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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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@ -298,6 +310,9 @@ class PngStream(ChunkStream):
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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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@ -309,6 +324,18 @@ class PngStream(ChunkStream):
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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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@ -356,7 +383,15 @@ class PngStream(ChunkStream):
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def chunk_IDAT(self, pos, length):
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# image data
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self.im_tile = [("zip", (0, 0) + self.im_size, pos, self.im_rawmode)]
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if "bbox" in self.im_info:
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tile = [(
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"zip", self.im_info["bbox"], pos, self.im_rawmode
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)]
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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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@ -537,9 +572,48 @@ class PngStream(ChunkStream):
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# APNG chunks
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def chunk_acTL(self, pos, length):
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s = ImageFile._safe_read(self.fp, length)
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if self.im_n_frames is not None:
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self.im_n_frames = None
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warnings.warn("Invalid APNG, will use default PNG image if possible")
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return s
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n_frames = i32(s)
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if n_frames == 0 or n_frames > 0x80000000:
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warnings.warn("Invalid APNG, will use default PNG image if possible")
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return s
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self.im_n_frames = n_frames
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self.im_info["loop"] = i32(s[4:])
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self.im_custom_mimetype = "image/apng"
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return s
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def chunk_fcTL(self, pos, length):
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s = ImageFile._safe_read(self.fp, length)
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seq = i32(s)
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if (self._seq_num is None and seq != 0) or \
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(self._seq_num is not None and self._seq_num != seq - 1):
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raise SyntaxError("APNG contains frame sequence errors")
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self._seq_num = seq
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width, height = i32(s[4:]), i32(s[8:])
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px, py = i32(s[12:]), i32(s[16:])
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im_w, im_h = self.im_size
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if px + width > im_w or py + height > im_h:
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raise SyntaxError("APNG contains invalid frames")
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self.im_info["bbox"] = (px, py, px + width, py + height)
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delay_num, delay_den = i16(s[20:]), i16(s[22:])
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if delay_den == 0:
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delay_den = 100
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self.im_info["duration"] = float(delay_num) / float(delay_den) * 1000
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self.im_info["disposal"] = i8(s[24])
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self.im_info["blend"] = i8(s[25])
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return s
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def chunk_fdAT(self, pos, length):
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s = ImageFile._safe_read(self.fp, 4)
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seq = i32(s)
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if self._seq_num != seq - 1:
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raise SyntaxError("APNG contains frame sequence errors")
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self._seq_num = seq
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return self.chunk_IDAT(pos + 4, length - 4)
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# --------------------------------------------------------------------
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# PNG reader
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@ -562,9 +636,11 @@ class PngImageFile(ImageFile.ImageFile):
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if self.fp.read(8) != _MAGIC:
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raise SyntaxError("not a PNG file")
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self.__fp = self.fp
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#
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# Parse headers up to the first IDAT chunk
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# Parse headers up to the first IDAT chunk (or last fdAT chunk for
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# APNG)
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self.png = PngStream(self.fp)
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@ -598,12 +674,27 @@ class PngImageFile(ImageFile.ImageFile):
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self._text = None
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self.tile = self.png.im_tile
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self.custom_mimetype = self.png.im_custom_mimetype
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self._n_frames = self.png.im_n_frames
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self.default_image = self.info.get("default_image", False)
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if self.png.im_palette:
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rawmode, data = self.png.im_palette
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self.palette = ImagePalette.raw(rawmode, data)
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self.__prepare_idat = length # used by load_prepare()
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if cid == b"fdAT":
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self.__prepare_idat = length - 4
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else:
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self.__prepare_idat = length # used by load_prepare()
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if self._n_frames is not None:
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self._close_exclusive_fp_after_loading = False
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self.png.save_rewind()
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self.__rewind_idat = self.__prepare_idat
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self.__rewind = self.__fp.tell()
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if self.default_image:
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# IDAT chunk contains default image and not first animation frame
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self._n_frames += 1
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self._seek(0)
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@property
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def text(self):
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@ -611,9 +702,25 @@ class PngImageFile(ImageFile.ImageFile):
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if self._text is None:
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# iTxt, tEXt and zTXt chunks may appear at the end of the file
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# So load the file to ensure that they are read
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if self.is_animated:
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frame = self.__frame
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# for APNG, seek to the final frame before loading
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self.seek(self.n_frames - 1)
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self.load()
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if self.is_animated:
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self.seek(frame)
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return self._text
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@property
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def n_frames(self):
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if self._n_frames is None:
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return 1
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return self._n_frames
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@property
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def is_animated(self):
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return self._n_frames is not None
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def verify(self):
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"""Verify PNG file"""
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@ -630,6 +737,95 @@ class PngImageFile(ImageFile.ImageFile):
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self.fp.close()
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self.fp = None
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def seek(self, frame):
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if not self._seek_check(frame):
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return
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if frame < self.__frame:
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self._seek(0, True)
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last_frame = self.__frame
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for f in range(self.__frame + 1, frame + 1):
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try:
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self._seek(f)
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except EOFError:
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self.seek(last_frame)
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raise EOFError("no more images in APNG file")
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def _seek(self, frame, rewind=False):
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if frame == 0:
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if rewind:
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self.__fp.seek(self.__rewind)
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self.png.rewind()
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self.__prepare_idat = self.__rewind_idat
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self.im = None
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self.info = self.png.im_info
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self.tile = self.png.im_tile
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self.fp = self.__fp
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self._prev_im = None
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self.dispose = None
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self.default_image = self.info.get("default_image", False)
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self.dispose_op = self.info.get("disposal")
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self.blend_op = self.info.get("blend")
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self.dispose_extent = self.info.get("bbox")
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self.__frame = 0
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return
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else:
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if frame != self.__frame + 1:
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raise ValueError("cannot seek to frame %d" % frame)
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# ensure previous frame was loaded
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self.load()
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self.fp = self.__fp
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# advance to the next frame
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if self.__prepare_idat:
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ImageFile._safe_read(self.fp, self.__prepare_idat)
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self.__prepare_idat = 0
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frame_start = False
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while True:
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self.fp.read(4) # CRC
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try:
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cid, pos, length = self.png.read()
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except (struct.error, SyntaxError):
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break
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if cid == b"IEND":
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raise EOFError("No more images in APNG file")
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if cid == b"fcTL":
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if frame_start:
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# there must be at least one fdAT chunk between fcTL chunks
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raise SyntaxError("APNG missing frame data")
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frame_start = True
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try:
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self.png.call(cid, pos, length)
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except UnicodeDecodeError:
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break
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except EOFError:
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if cid == b"fdAT":
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length -= 4
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if frame_start:
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self.__prepare_idat = length
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break
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ImageFile._safe_read(self.fp, length)
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except AttributeError:
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logger.debug("%r %s %s (unknown)", cid, pos, length)
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ImageFile._safe_read(self.fp, length)
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self.__frame = frame
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self.tile = self.png.im_tile
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self.dispose_op = self.info.get("disposal")
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self.blend_op = self.info.get("blend")
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self.dispose_extent = self.info.get("bbox")
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if not self.tile:
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raise EOFError
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def tell(self):
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return self.__frame
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def load_prepare(self):
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"""internal: prepare to read PNG file"""
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@ -649,11 +845,18 @@ class PngImageFile(ImageFile.ImageFile):
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cid, pos, length = self.png.read()
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if cid not in [b"IDAT", b"DDAT"]:
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if cid not in [b"IDAT", b"DDAT", b"fdAT"]:
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self.png.push(cid, pos, length)
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return b""
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self.__idat = length # empty chunks are allowed
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if cid == b"fdAT":
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try:
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self.png.call(cid, pos, length)
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except EOFError:
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pass
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self.__idat = length - 4 # sequence_num has already been read
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else:
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self.__idat = length # empty chunks are allowed
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# read more data from this chunk
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if read_bytes <= 0:
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@ -677,19 +880,50 @@ class PngImageFile(ImageFile.ImageFile):
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if cid == b"IEND":
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break
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elif cid == b"fcTL" and self.is_animated:
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# start of the next frame, stop reading
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self.__prepare_idat = 0
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self.png.push(cid, pos, length)
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break
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try:
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self.png.call(cid, pos, length)
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except UnicodeDecodeError:
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break
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except EOFError:
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if cid == b"fdAT":
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length -= 4
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ImageFile._safe_read(self.fp, length)
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except AttributeError:
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logger.debug("%r %s %s (unknown)", cid, pos, length)
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ImageFile._safe_read(self.fp, length)
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self._text = self.png.im_text
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self.png.close()
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self.png = None
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if not self.is_animated:
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self.png.close()
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self.png = None
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else:
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# setup frame disposal (actual disposal done when needed in _seek())
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if self._prev_im is None and self.dispose_op == APNG_DISPOSE_OP_PREVIOUS:
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self.dispose_op = APNG_DISPOSE_OP_BACKGROUND
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if self.dispose_op == APNG_DISPOSE_OP_PREVIOUS:
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dispose = self._prev_im.copy()
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dispose = self._crop(dispose, self.dispose_extent)
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elif self.dispose_op == APNG_DISPOSE_OP_BACKGROUND:
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dispose = Image.core.fill("RGBA", self.size, (0, 0, 0, 0))
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dispose = self._crop(dispose, self.dispose_extent)
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else:
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dispose = None
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if self._prev_im and self.blend_op == APNG_BLEND_OP_OVER:
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updated = self._crop(self.im, self.dispose_extent)
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self._prev_im.paste(
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updated, self.dispose_extent, updated.convert("RGBA"))
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self.im = self._prev_im
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self._prev_im = self.im.copy()
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if dispose:
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self._prev_im.paste(dispose, self.dispose_extent)
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def _getexif(self):
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if "exif" not in self.info:
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@ -703,6 +937,15 @@ class PngImageFile(ImageFile.ImageFile):
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self.load()
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return ImageFile.ImageFile.getexif(self)
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def _close__fp(self):
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try:
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if self.__fp != self.fp:
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self.__fp.close()
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except AttributeError:
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pass
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finally:
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self.__fp = None
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# --------------------------------------------------------------------
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# PNG writer
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@ -748,7 +991,139 @@ class _idat:
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self.chunk(self.fp, b"IDAT", data)
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def _save(im, fp, filename, chunk=putchunk):
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class _fdat:
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# wrap encoder output in fdAT chunks
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def __init__(self, fp, chunk, seq_num):
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self.fp = fp
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self.chunk = chunk
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self.seq_num = seq_num
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def write(self, data):
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self.chunk(self.fp, b"fdAT", o32(self.seq_num), data)
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def _write_multiple_frames(im, fp, chunk, rawmode):
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default_image = im.encoderinfo.get("default_image", im.info.get("default_image"))
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duration = im.encoderinfo.get("duration", im.info.get("duration", 0))
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loop = im.encoderinfo.get("loop", im.info.get("loop", 0))
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disposal = im.encoderinfo.get("disposal", im.info.get("disposal"))
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blend = im.encoderinfo.get("blend", im.info.get("blend"))
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if default_image:
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chain = itertools.chain(im.encoderinfo.get("append_images", []))
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else:
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chain = itertools.chain([im], im.encoderinfo.get("append_images", []))
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im_frames = []
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frame_count = 0
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for im_seq in chain:
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for im_frame in ImageSequence.Iterator(im_seq):
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im_frame = im_frame.copy()
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if im_frame.mode != im.mode:
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if im.mode == "P":
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im_frame = im_frame.convert(im.mode, palette=im.palette)
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else:
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im_frame = im_frame.convert(im.mode)
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encoderinfo = im.encoderinfo.copy()
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if isinstance(duration, (list, tuple)):
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encoderinfo["duration"] = duration[frame_count]
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if isinstance(disposal, (list, tuple)):
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encoderinfo["disposal"] = disposal[frame_count]
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if isinstance(blend, (list, tuple)):
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encoderinfo["blend"] = blend[frame_count]
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frame_count += 1
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if im_frames:
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previous = im_frames[-1]
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prev_disposal = previous["encoderinfo"].get("disposal")
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prev_blend = previous["encoderinfo"].get("blend")
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if prev_disposal == APNG_DISPOSE_OP_PREVIOUS and len(im_frames) < 2:
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prev_disposal == APNG_DISPOSE_OP_BACKGROUND
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if prev_disposal == APNG_DISPOSE_OP_BACKGROUND:
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base_im = previous["im"]
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dispose = Image.core.fill("RGBA", im.size, (0, 0, 0, 0))
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bbox = previous["bbox"]
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if bbox:
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dispose = dispose.crop(bbox)
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else:
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bbox = (0, 0) + im.size
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base_im.paste(dispose, bbox)
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elif prev_disposal == APNG_DISPOSE_OP_PREVIOUS:
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base_im = im_frames[-2]["im"]
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else:
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base_im = previous["im"]
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delta = ImageChops.subtract_modulo(im_frame, base_im)
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bbox = delta.getbbox()
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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)), # 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
|
||||
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:
|
||||
ImageFile._save(im_frame, _fdat(fp, chunk, seq_num),
|
||||
[("zip", (0, 0) + im_frame.size, 0, rawmode)])
|
||||
seq_num += 1
|
||||
|
||||
|
||||
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
|
||||
|
|
@ -897,7 +1272,10 @@ def _save(im, fp, filename, chunk=putchunk):
|
|||
exif = exif[6:]
|
||||
chunk(fp, b"eXIf", exif)
|
||||
|
||||
ImageFile._save(im, _idat(fp, chunk), [("zip", (0, 0) + im.size, 0, rawmode)])
|
||||
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"")
|
||||
|
||||
|
|
@ -942,6 +1320,7 @@ def getchunks(im, **params):
|
|||
|
||||
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"])
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user