815 lines
26 KiB
Python
815 lines
26 KiB
Python
|
#
|
||
|
|
# The Python Imaging Library.
|
||
|
|
# $Id$
|
||
|
|
#
|
||
|
|
# GIF file handling
|
||
|
|
#
|
||
|
|
# History:
|
||
|
|
# 1995-09-01 fl Created
|
||
|
|
# 1996-12-14 fl Added interlace support
|
||
|
|
# 1996-12-30 fl Added animation support
|
||
|
|
# 1997-01-05 fl Added write support, fixed local colour map bug
|
||
|
|
# 1997-02-23 fl Make sure to load raster data in getdata()
|
||
|
|
# 1997-07-05 fl Support external decoder (0.4)
|
||
|
|
# 1998-07-09 fl Handle all modes when saving (0.5)
|
||
|
|
# 1998-07-15 fl Renamed offset attribute to avoid name clash
|
||
|
|
# 2001-04-16 fl Added rewind support (seek to frame 0) (0.6)
|
||
|
|
# 2001-04-17 fl Added palette optimization (0.7)
|
||
|
|
# 2002-06-06 fl Added transparency support for save (0.8)
|
||
|
|
# 2004-02-24 fl Disable interlacing for small images
|
||
|
|
#
|
||
|
|
# Copyright (c) 1997-2004 by Secret Labs AB
|
||
|
|
# Copyright (c) 1995-2004 by Fredrik Lundh
|
||
|
|
#
|
||
|
|
# See the README file for information on usage and redistribution.
|
||
|
|
#
|
||
|
|
|
||
|
|
from . import Image, ImageFile, ImagePalette, ImageChops, ImageSequence
|
||
|
|
from ._binary import i8, i16le as i16, o8, o16le as o16
|
||
|
|
|
||
|
|
import itertools
|
||
|
|
|
||
|
|
__version__ = "0.9"
|
||
|
|
|
||
|
|
|
||
|
|
# --------------------------------------------------------------------
|
||
|
|
# Identify/read GIF files
|
||
|
|
|
||
|
|
def _accept(prefix):
|
||
|
|
return prefix[:6] in [b"GIF87a", b"GIF89a"]
|
||
|
|
|
||
|
|
|
||
|
|
##
|
||
|
|
# Image plugin for GIF images. This plugin supports both GIF87 and
|
||
|
|
# GIF89 images.
|
||
|
|
|
||
|
|
class GifImageFile(ImageFile.ImageFile):
|
||
|
|
|
||
|
|
format = "GIF"
|
||
|
|
format_description = "Compuserve GIF"
|
||
|
|
_close_exclusive_fp_after_loading = False
|
||
|
|
|
||
|
|
global_palette = None
|
||
|
|
|
||
|
|
def data(self):
|
||
|
|
s = self.fp.read(1)
|
||
|
|
if s and i8(s):
|
||
|
|
return self.fp.read(i8(s))
|
||
|
|
return None
|
||
|
|
|
||
|
|
def _open(self):
|
||
|
|
|
||
|
|
# Screen
|
||
|
|
s = self.fp.read(13)
|
||
|
|
if s[:6] not in [b"GIF87a", b"GIF89a"]:
|
||
|
|
raise SyntaxError("not a GIF file")
|
||
|
|
|
||
|
|
self.info["version"] = s[:6]
|
||
|
|
self.size = i16(s[6:]), i16(s[8:])
|
||
|
|
self.tile = []
|
||
|
|
flags = i8(s[10])
|
||
|
|
bits = (flags & 7) + 1
|
||
|
|
|
||
|
|
if flags & 128:
|
||
|
|
# get global palette
|
||
|
|
self.info["background"] = i8(s[11])
|
||
|
|
# check if palette contains colour indices
|
||
|
|
p = self.fp.read(3 << bits)
|
||
|
|
for i in range(0, len(p), 3):
|
||
|
|
if not (i//3 == i8(p[i]) == i8(p[i+1]) == i8(p[i+2])):
|
||
|
|
p = ImagePalette.raw("RGB", p)
|
||
|
|
self.global_palette = self.palette = p
|
||
|
|
break
|
||
|
|
|
||
|
|
self.__fp = self.fp # FIXME: hack
|
||
|
|
self.__rewind = self.fp.tell()
|
||
|
|
self._n_frames = None
|
||
|
|
self._is_animated = None
|
||
|
|
self._seek(0) # get ready to read first frame
|
||
|
|
|
||
|
|
@property
|
||
|
|
def n_frames(self):
|
||
|
|
if self._n_frames is None:
|
||
|
|
current = self.tell()
|
||
|
|
try:
|
||
|
|
while True:
|
||
|
|
self.seek(self.tell() + 1)
|
||
|
|
except EOFError:
|
||
|
|
self._n_frames = self.tell() + 1
|
||
|
|
self.seek(current)
|
||
|
|
return self._n_frames
|
||
|
|
|
||
|
|
@property
|
||
|
|
def is_animated(self):
|
||
|
|
if self._is_animated is None:
|
||
|
|
if self._n_frames is not None:
|
||
|
|
self._is_animated = self._n_frames != 1
|
||
|
|
else:
|
||
|
|
current = self.tell()
|
||
|
|
|
||
|
|
try:
|
||
|
|
self.seek(1)
|
||
|
|
self._is_animated = True
|
||
|
|
except EOFError:
|
||
|
|
self._is_animated = False
|
||
|
|
|
||
|
|
self.seek(current)
|
||
|
|
return self._is_animated
|
||
|
|
|
||
|
|
def seek(self, frame):
|
||
|
|
if not self._seek_check(frame):
|
||
|
|
return
|
||
|
|
if frame < self.__frame:
|
||
|
|
self._seek(0)
|
||
|
|
|
||
|
|
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 GIF file")
|
||
|
|
|
||
|
|
def _seek(self, frame):
|
||
|
|
|
||
|
|
if frame == 0:
|
||
|
|
# rewind
|
||
|
|
self.__offset = 0
|
||
|
|
self.dispose = None
|
||
|
|
self.dispose_extent = [0, 0, 0, 0] # x0, y0, x1, y1
|
||
|
|
self.__frame = -1
|
||
|
|
self.__fp.seek(self.__rewind)
|
||
|
|
self._prev_im = None
|
||
|
|
self.disposal_method = 0
|
||
|
|
else:
|
||
|
|
# ensure that the previous frame was loaded
|
||
|
|
if not self.im:
|
||
|
|
self.load()
|
||
|
|
|
||
|
|
if frame != self.__frame + 1:
|
||
|
|
raise ValueError("cannot seek to frame %d" % frame)
|
||
|
|
self.__frame = frame
|
||
|
|
|
||
|
|
self.tile = []
|
||
|
|
|
||
|
|
self.fp = self.__fp
|
||
|
|
if self.__offset:
|
||
|
|
# backup to last frame
|
||
|
|
self.fp.seek(self.__offset)
|
||
|
|
while self.data():
|
||
|
|
pass
|
||
|
|
self.__offset = 0
|
||
|
|
|
||
|
|
if self.dispose:
|
||
|
|
self.im.paste(self.dispose, self.dispose_extent)
|
||
|
|
|
||
|
|
from copy import copy
|
||
|
|
self.palette = copy(self.global_palette)
|
||
|
|
|
||
|
|
while True:
|
||
|
|
|
||
|
|
s = self.fp.read(1)
|
||
|
|
if not s or s == b";":
|
||
|
|
break
|
||
|
|
|
||
|
|
elif s == b"!":
|
||
|
|
#
|
||
|
|
# extensions
|
||
|
|
#
|
||
|
|
s = self.fp.read(1)
|
||
|
|
block = self.data()
|
||
|
|
if i8(s) == 249:
|
||
|
|
#
|
||
|
|
# graphic control extension
|
||
|
|
#
|
||
|
|
flags = i8(block[0])
|
||
|
|
if flags & 1:
|
||
|
|
self.info["transparency"] = i8(block[3])
|
||
|
|
self.info["duration"] = i16(block[1:3]) * 10
|
||
|
|
|
||
|
|
# disposal method - find the value of bits 4 - 6
|
||
|
|
dispose_bits = 0b00011100 & flags
|
||
|
|
dispose_bits = dispose_bits >> 2
|
||
|
|
if dispose_bits:
|
||
|
|
# only set the dispose if it is not
|
||
|
|
# unspecified. I'm not sure if this is
|
||
|
|
# correct, but it seems to prevent the last
|
||
|
|
# frame from looking odd for some animations
|
||
|
|
self.disposal_method = dispose_bits
|
||
|
|
elif i8(s) == 254:
|
||
|
|
#
|
||
|
|
# comment extension
|
||
|
|
#
|
||
|
|
self.info["comment"] = block
|
||
|
|
elif i8(s) == 255:
|
||
|
|
#
|
||
|
|
# application extension
|
||
|
|
#
|
||
|
|
self.info["extension"] = block, self.fp.tell()
|
||
|
|
if block[:11] == b"NETSCAPE2.0":
|
||
|
|
block = self.data()
|
||
|
|
if len(block) >= 3 and i8(block[0]) == 1:
|
||
|
|
self.info["loop"] = i16(block[1:3])
|
||
|
|
while self.data():
|
||
|
|
pass
|
||
|
|
|
||
|
|
elif s == b",":
|
||
|
|
#
|
||
|
|
# local image
|
||
|
|
#
|
||
|
|
s = self.fp.read(9)
|
||
|
|
|
||
|
|
# extent
|
||
|
|
x0, y0 = i16(s[0:]), i16(s[2:])
|
||
|
|
x1, y1 = x0 + i16(s[4:]), y0 + i16(s[6:])
|
||
|
|
self.dispose_extent = x0, y0, x1, y1
|
||
|
|
flags = i8(s[8])
|
||
|
|
|
||
|
|
interlace = (flags & 64) != 0
|
||
|
|
|
||
|
|
if flags & 128:
|
||
|
|
bits = (flags & 7) + 1
|
||
|
|
self.palette =\
|
||
|
|
ImagePalette.raw("RGB", self.fp.read(3 << bits))
|
||
|
|
|
||
|
|
# image data
|
||
|
|
bits = i8(self.fp.read(1))
|
||
|
|
self.__offset = self.fp.tell()
|
||
|
|
self.tile = [("gif",
|
||
|
|
(x0, y0, x1, y1),
|
||
|
|
self.__offset,
|
||
|
|
(bits, interlace))]
|
||
|
|
break
|
||
|
|
|
||
|
|
else:
|
||
|
|
pass
|
||
|
|
# raise IOError, "illegal GIF tag `%x`" % i8(s)
|
||
|
|
|
||
|
|
try:
|
||
|
|
if self.disposal_method < 2:
|
||
|
|
# do not dispose or none specified
|
||
|
|
self.dispose = None
|
||
|
|
elif self.disposal_method == 2:
|
||
|
|
# replace with background colour
|
||
|
|
self.dispose = Image.core.fill("P", self.size,
|
||
|
|
self.info["background"])
|
||
|
|
else:
|
||
|
|
# replace with previous contents
|
||
|
|
if self.im:
|
||
|
|
self.dispose = self.im.copy()
|
||
|
|
|
||
|
|
# only dispose the extent in this frame
|
||
|
|
if self.dispose:
|
||
|
|
self.dispose = self._crop(self.dispose, self.dispose_extent)
|
||
|
|
except (AttributeError, KeyError):
|
||
|
|
pass
|
||
|
|
|
||
|
|
if not self.tile:
|
||
|
|
# self.__fp = None
|
||
|
|
raise EOFError
|
||
|
|
|
||
|
|
self.mode = "L"
|
||
|
|
if self.palette:
|
||
|
|
self.mode = "P"
|
||
|
|
|
||
|
|
def tell(self):
|
||
|
|
return self.__frame
|
||
|
|
|
||
|
|
def load_end(self):
|
||
|
|
ImageFile.ImageFile.load_end(self)
|
||
|
|
|
||
|
|
# if the disposal method is 'do not dispose', transparent
|
||
|
|
# pixels should show the content of the previous frame
|
||
|
|
if self._prev_im and self.disposal_method == 1:
|
||
|
|
# we do this by pasting the updated area onto the previous
|
||
|
|
# frame which we then use as the current image content
|
||
|
|
updated = self._crop(self.im, self.dispose_extent)
|
||
|
|
self._prev_im.paste(updated, self.dispose_extent,
|
||
|
|
updated.convert('RGBA'))
|
||
|
|
self.im = self._prev_im
|
||
|
|
self._prev_im = self.im.copy()
|
||
|
|
|
||
|
|
# --------------------------------------------------------------------
|
||
|
|
# Write GIF files
|
||
|
|
|
||
|
|
|
||
|
|
RAWMODE = {
|
||
|
|
"1": "L",
|
||
|
|
"L": "L",
|
||
|
|
"P": "P"
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
def _normalize_mode(im, initial_call=False):
|
||
|
|
"""
|
||
|
|
Takes an image (or frame), returns an image in a mode that is appropriate
|
||
|
|
for saving in a Gif.
|
||
|
|
|
||
|
|
It may return the original image, or it may return an image converted to
|
||
|
|
palette or 'L' mode.
|
||
|
|
|
||
|
|
UNDONE: What is the point of mucking with the initial call palette, for
|
||
|
|
an image that shouldn't have a palette, or it would be a mode 'P' and
|
||
|
|
get returned in the RAWMODE clause.
|
||
|
|
|
||
|
|
:param im: Image object
|
||
|
|
:param initial_call: Default false, set to true for a single frame.
|
||
|
|
:returns: Image object
|
||
|
|
"""
|
||
|
|
if im.mode in RAWMODE:
|
||
|
|
im.load()
|
||
|
|
return im
|
||
|
|
if Image.getmodebase(im.mode) == "RGB":
|
||
|
|
if initial_call:
|
||
|
|
palette_size = 256
|
||
|
|
if im.palette:
|
||
|
|
palette_size = len(im.palette.getdata()[1]) // 3
|
||
|
|
return im.convert("P", palette=Image.ADAPTIVE, colors=palette_size)
|
||
|
|
else:
|
||
|
|
return im.convert("P")
|
||
|
|
return im.convert("L")
|
||
|
|
|
||
|
|
|
||
|
|
def _normalize_palette(im, palette, info):
|
||
|
|
"""
|
||
|
|
Normalizes the palette for image.
|
||
|
|
- Sets the palette to the incoming palette, if provided.
|
||
|
|
- Ensures that there's a palette for L mode images
|
||
|
|
- Optimizes the palette if necessary/desired.
|
||
|
|
|
||
|
|
:param im: Image object
|
||
|
|
:param palette: bytes object containing the source palette, or ....
|
||
|
|
:param info: encoderinfo
|
||
|
|
:returns: Image object
|
||
|
|
"""
|
||
|
|
source_palette = None
|
||
|
|
if palette:
|
||
|
|
# a bytes palette
|
||
|
|
if isinstance(palette, (bytes, bytearray, list)):
|
||
|
|
source_palette = bytearray(palette[:768])
|
||
|
|
if isinstance(palette, ImagePalette.ImagePalette):
|
||
|
|
source_palette = bytearray(itertools.chain.from_iterable(
|
||
|
|
zip(palette.palette[:256],
|
||
|
|
palette.palette[256:512],
|
||
|
|
palette.palette[512:768])))
|
||
|
|
|
||
|
|
if im.mode == "P":
|
||
|
|
if not source_palette:
|
||
|
|
source_palette = im.im.getpalette("RGB")[:768]
|
||
|
|
else: # L-mode
|
||
|
|
if not source_palette:
|
||
|
|
source_palette = bytearray(i//3 for i in range(768))
|
||
|
|
im.palette = ImagePalette.ImagePalette("RGB",
|
||
|
|
palette=source_palette)
|
||
|
|
|
||
|
|
used_palette_colors = _get_optimize(im, info)
|
||
|
|
if used_palette_colors is not None:
|
||
|
|
return im.remap_palette(used_palette_colors, source_palette)
|
||
|
|
|
||
|
|
im.palette.palette = source_palette
|
||
|
|
return im
|
||
|
|
|
||
|
|
|
||
|
|
def _write_single_frame(im, fp, palette):
|
||
|
|
im_out = _normalize_mode(im, True)
|
||
|
|
im_out = _normalize_palette(im_out, palette, im.encoderinfo)
|
||
|
|
|
||
|
|
for s in _get_global_header(im_out, im.encoderinfo):
|
||
|
|
fp.write(s)
|
||
|
|
|
||
|
|
# local image header
|
||
|
|
flags = 0
|
||
|
|
if get_interlace(im):
|
||
|
|
flags = flags | 64
|
||
|
|
_write_local_header(fp, im, (0, 0), flags)
|
||
|
|
|
||
|
|
im_out.encoderconfig = (8, get_interlace(im))
|
||
|
|
ImageFile._save(im_out, fp, [("gif", (0, 0)+im.size, 0,
|
||
|
|
RAWMODE[im_out.mode])])
|
||
|
|
|
||
|
|
fp.write(b"\0") # end of image data
|
||
|
|
|
||
|
|
|
||
|
|
def _write_multiple_frames(im, fp, palette):
|
||
|
|
|
||
|
|
duration = im.encoderinfo.get("duration", None)
|
||
|
|
disposal = im.encoderinfo.get('disposal', None)
|
||
|
|
|
||
|
|
im_frames = []
|
||
|
|
frame_count = 0
|
||
|
|
for imSequence in itertools.chain([im], im.encoderinfo.get("append_images", [])):
|
||
|
|
for im_frame in ImageSequence.Iterator(imSequence):
|
||
|
|
# a copy is required here since seek can still mutate the image
|
||
|
|
im_frame = _normalize_mode(im_frame.copy())
|
||
|
|
im_frame = _normalize_palette(im_frame, palette, im.encoderinfo)
|
||
|
|
|
||
|
|
encoderinfo = im.encoderinfo.copy()
|
||
|
|
if isinstance(duration, (list, tuple)):
|
||
|
|
encoderinfo['duration'] = duration[frame_count]
|
||
|
|
if isinstance(disposal, (list, tuple)):
|
||
|
|
encoderinfo["disposal"] = disposal[frame_count]
|
||
|
|
frame_count += 1
|
||
|
|
|
||
|
|
if im_frames:
|
||
|
|
# delta frame
|
||
|
|
previous = im_frames[-1]
|
||
|
|
if _get_palette_bytes(im_frame) == _get_palette_bytes(previous['im']):
|
||
|
|
delta = ImageChops.subtract_modulo(im_frame,
|
||
|
|
previous['im'])
|
||
|
|
else:
|
||
|
|
delta = ImageChops.subtract_modulo(im_frame.convert('RGB'),
|
||
|
|
previous['im'].convert('RGB'))
|
||
|
|
bbox = delta.getbbox()
|
||
|
|
if not bbox:
|
||
|
|
# This frame is identical to the previous frame
|
||
|
|
if duration:
|
||
|
|
previous['encoderinfo']['duration'] += encoderinfo['duration']
|
||
|
|
continue
|
||
|
|
else:
|
||
|
|
bbox = None
|
||
|
|
im_frames.append({
|
||
|
|
'im': im_frame,
|
||
|
|
'bbox': bbox,
|
||
|
|
'encoderinfo': encoderinfo
|
||
|
|
})
|
||
|
|
|
||
|
|
if len(im_frames) > 1:
|
||
|
|
for frame_data in im_frames:
|
||
|
|
im_frame = frame_data['im']
|
||
|
|
if not frame_data['bbox']:
|
||
|
|
# global header
|
||
|
|
for s in _get_global_header(im_frame,
|
||
|
|
frame_data['encoderinfo']):
|
||
|
|
fp.write(s)
|
||
|
|
offset = (0, 0)
|
||
|
|
else:
|
||
|
|
# compress difference
|
||
|
|
frame_data['encoderinfo']['include_color_table'] = True
|
||
|
|
|
||
|
|
im_frame = im_frame.crop(frame_data['bbox'])
|
||
|
|
offset = frame_data['bbox'][:2]
|
||
|
|
_write_frame_data(fp, im_frame, offset, frame_data['encoderinfo'])
|
||
|
|
return True
|
||
|
|
|
||
|
|
|
||
|
|
def _save_all(im, fp, filename):
|
||
|
|
_save(im, fp, filename, save_all=True)
|
||
|
|
|
||
|
|
|
||
|
|
def _save(im, fp, filename, save_all=False):
|
||
|
|
for k, v in im.info.items():
|
||
|
|
im.encoderinfo.setdefault(k, v)
|
||
|
|
# header
|
||
|
|
try:
|
||
|
|
palette = im.encoderinfo["palette"]
|
||
|
|
except KeyError:
|
||
|
|
palette = None
|
||
|
|
im.encoderinfo["optimize"] = im.encoderinfo.get("optimize", True)
|
||
|
|
|
||
|
|
if not save_all or not _write_multiple_frames(im, fp, palette):
|
||
|
|
_write_single_frame(im, fp, palette)
|
||
|
|
|
||
|
|
fp.write(b";") # end of file
|
||
|
|
|
||
|
|
if hasattr(fp, "flush"):
|
||
|
|
fp.flush()
|
||
|
|
|
||
|
|
|
||
|
|
def get_interlace(im):
|
||
|
|
interlace = im.encoderinfo.get("interlace", 1)
|
||
|
|
|
||
|
|
# workaround for @PIL153
|
||
|
|
if min(im.size) < 16:
|
||
|
|
interlace = 0
|
||
|
|
|
||
|
|
return interlace
|
||
|
|
|
||
|
|
|
||
|
|
def _write_local_header(fp, im, offset, flags):
|
||
|
|
transparent_color_exists = False
|
||
|
|
try:
|
||
|
|
transparency = im.encoderinfo["transparency"]
|
||
|
|
except KeyError:
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
transparency = int(transparency)
|
||
|
|
# optimize the block away if transparent color is not used
|
||
|
|
transparent_color_exists = True
|
||
|
|
|
||
|
|
used_palette_colors = _get_optimize(im, im.encoderinfo)
|
||
|
|
if used_palette_colors is not None:
|
||
|
|
# adjust the transparency index after optimize
|
||
|
|
try:
|
||
|
|
transparency = used_palette_colors.index(transparency)
|
||
|
|
except ValueError:
|
||
|
|
transparent_color_exists = False
|
||
|
|
|
||
|
|
if "duration" in im.encoderinfo:
|
||
|
|
duration = int(im.encoderinfo["duration"] / 10)
|
||
|
|
else:
|
||
|
|
duration = 0
|
||
|
|
|
||
|
|
disposal = int(im.encoderinfo.get('disposal', 0))
|
||
|
|
|
||
|
|
if transparent_color_exists or duration != 0 or disposal:
|
||
|
|
packed_flag = 1 if transparent_color_exists else 0
|
||
|
|
packed_flag |= disposal << 2
|
||
|
|
if not transparent_color_exists:
|
||
|
|
transparency = 0
|
||
|
|
|
||
|
|
fp.write(b"!" +
|
||
|
|
o8(249) + # extension intro
|
||
|
|
o8(4) + # length
|
||
|
|
o8(packed_flag) + # packed fields
|
||
|
|
o16(duration) + # duration
|
||
|
|
o8(transparency) + # transparency index
|
||
|
|
o8(0))
|
||
|
|
|
||
|
|
if "comment" in im.encoderinfo and 1 <= len(im.encoderinfo["comment"]) <= 255:
|
||
|
|
fp.write(b"!" +
|
||
|
|
o8(254) + # extension intro
|
||
|
|
o8(len(im.encoderinfo["comment"])) +
|
||
|
|
im.encoderinfo["comment"] +
|
||
|
|
o8(0))
|
||
|
|
if "loop" in im.encoderinfo:
|
||
|
|
number_of_loops = im.encoderinfo["loop"]
|
||
|
|
fp.write(b"!" +
|
||
|
|
o8(255) + # extension intro
|
||
|
|
o8(11) +
|
||
|
|
b"NETSCAPE2.0" +
|
||
|
|
o8(3) +
|
||
|
|
o8(1) +
|
||
|
|
o16(number_of_loops) + # number of loops
|
||
|
|
o8(0))
|
||
|
|
include_color_table = im.encoderinfo.get('include_color_table')
|
||
|
|
if include_color_table:
|
||
|
|
palette = im.encoderinfo.get("palette", None)
|
||
|
|
palette_bytes = _get_palette_bytes(im)
|
||
|
|
color_table_size = _get_color_table_size(palette_bytes)
|
||
|
|
if color_table_size:
|
||
|
|
flags = flags | 128 # local color table flag
|
||
|
|
flags = flags | color_table_size
|
||
|
|
|
||
|
|
fp.write(b"," +
|
||
|
|
o16(offset[0]) + # offset
|
||
|
|
o16(offset[1]) +
|
||
|
|
o16(im.size[0]) + # size
|
||
|
|
o16(im.size[1]) +
|
||
|
|
o8(flags)) # flags
|
||
|
|
if include_color_table and color_table_size:
|
||
|
|
fp.write(_get_header_palette(palette_bytes))
|
||
|
|
fp.write(o8(8)) # bits
|
||
|
|
|
||
|
|
|
||
|
|
def _save_netpbm(im, fp, filename):
|
||
|
|
|
||
|
|
# Unused by default.
|
||
|
|
# To use, uncomment the register_save call at the end of the file.
|
||
|
|
#
|
||
|
|
# If you need real GIF compression and/or RGB quantization, you
|
||
|
|
# can use the external NETPBM/PBMPLUS utilities. See comments
|
||
|
|
# below for information on how to enable this.
|
||
|
|
|
||
|
|
import os
|
||
|
|
from subprocess import Popen, check_call, PIPE, CalledProcessError
|
||
|
|
file = im._dump()
|
||
|
|
|
||
|
|
with open(filename, 'wb') as f:
|
||
|
|
if im.mode != "RGB":
|
||
|
|
with open(os.devnull, 'wb') as devnull:
|
||
|
|
check_call(["ppmtogif", file], stdout=f, stderr=devnull)
|
||
|
|
else:
|
||
|
|
# Pipe ppmquant output into ppmtogif
|
||
|
|
# "ppmquant 256 %s | ppmtogif > %s" % (file, filename)
|
||
|
|
quant_cmd = ["ppmquant", "256", file]
|
||
|
|
togif_cmd = ["ppmtogif"]
|
||
|
|
with open(os.devnull, 'wb') as devnull:
|
||
|
|
quant_proc = Popen(quant_cmd, stdout=PIPE, stderr=devnull)
|
||
|
|
togif_proc = Popen(togif_cmd, stdin=quant_proc.stdout,
|
||
|
|
stdout=f, stderr=devnull)
|
||
|
|
|
||
|
|
# Allow ppmquant to receive SIGPIPE if ppmtogif exits
|
||
|
|
quant_proc.stdout.close()
|
||
|
|
|
||
|
|
retcode = quant_proc.wait()
|
||
|
|
if retcode:
|
||
|
|
raise CalledProcessError(retcode, quant_cmd)
|
||
|
|
|
||
|
|
retcode = togif_proc.wait()
|
||
|
|
if retcode:
|
||
|
|
raise CalledProcessError(retcode, togif_cmd)
|
||
|
|
|
||
|
|
try:
|
||
|
|
os.unlink(file)
|
||
|
|
except OSError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
# Force optimization so that we can test performance against
|
||
|
|
# cases where it took lots of memory and time previously.
|
||
|
|
_FORCE_OPTIMIZE = False
|
||
|
|
|
||
|
|
|
||
|
|
def _get_optimize(im, info):
|
||
|
|
"""
|
||
|
|
Palette optimization is a potentially expensive operation.
|
||
|
|
|
||
|
|
This function determines if the palette should be optimized using
|
||
|
|
some heuristics, then returns the list of palette entries in use.
|
||
|
|
|
||
|
|
:param im: Image object
|
||
|
|
:param info: encoderinfo
|
||
|
|
:returns: list of indexes of palette entries in use, or None
|
||
|
|
"""
|
||
|
|
if im.mode in ("P", "L") and info and info.get("optimize", 0):
|
||
|
|
# Potentially expensive operation.
|
||
|
|
|
||
|
|
# The palette saves 3 bytes per color not used, but palette
|
||
|
|
# lengths are restricted to 3*(2**N) bytes. Max saving would
|
||
|
|
# be 768 -> 6 bytes if we went all the way down to 2 colors.
|
||
|
|
# * If we're over 128 colors, we can't save any space.
|
||
|
|
# * If there aren't any holes, it's not worth collapsing.
|
||
|
|
# * If we have a 'large' image, the palette is in the noise.
|
||
|
|
|
||
|
|
# create the new palette if not every color is used
|
||
|
|
optimise = _FORCE_OPTIMIZE or im.mode == 'L'
|
||
|
|
if optimise or im.width * im.height < 512 * 512:
|
||
|
|
# check which colors are used
|
||
|
|
used_palette_colors = []
|
||
|
|
for i, count in enumerate(im.histogram()):
|
||
|
|
if count:
|
||
|
|
used_palette_colors.append(i)
|
||
|
|
|
||
|
|
if optimise or (len(used_palette_colors) <= 128 and
|
||
|
|
max(used_palette_colors) > len(used_palette_colors)):
|
||
|
|
return used_palette_colors
|
||
|
|
|
||
|
|
|
||
|
|
def _get_color_table_size(palette_bytes):
|
||
|
|
# calculate the palette size for the header
|
||
|
|
import math
|
||
|
|
color_table_size = int(math.ceil(math.log(len(palette_bytes)//3, 2)))-1
|
||
|
|
if color_table_size < 0:
|
||
|
|
color_table_size = 0
|
||
|
|
return color_table_size
|
||
|
|
|
||
|
|
|
||
|
|
def _get_header_palette(palette_bytes):
|
||
|
|
"""
|
||
|
|
Returns the palette, null padded to the next power of 2 (*3) bytes
|
||
|
|
suitable for direct inclusion in the GIF header
|
||
|
|
|
||
|
|
:param palette_bytes: Unpadded palette bytes, in RGBRGB form
|
||
|
|
:returns: Null padded palette
|
||
|
|
"""
|
||
|
|
color_table_size = _get_color_table_size(palette_bytes)
|
||
|
|
|
||
|
|
# add the missing amount of bytes
|
||
|
|
# the palette has to be 2<<n in size
|
||
|
|
actual_target_size_diff = (2 << color_table_size) - len(palette_bytes)//3
|
||
|
|
if actual_target_size_diff > 0:
|
||
|
|
palette_bytes += o8(0) * 3 * actual_target_size_diff
|
||
|
|
return palette_bytes
|
||
|
|
|
||
|
|
|
||
|
|
def _get_palette_bytes(im):
|
||
|
|
"""
|
||
|
|
Gets the palette for inclusion in the gif header
|
||
|
|
|
||
|
|
:param im: Image object
|
||
|
|
:returns: Bytes, len<=768 suitable for inclusion in gif header
|
||
|
|
"""
|
||
|
|
return im.palette.palette
|
||
|
|
|
||
|
|
|
||
|
|
def _get_global_header(im, info):
|
||
|
|
"""Return a list of strings representing a GIF header"""
|
||
|
|
|
||
|
|
# Header Block
|
||
|
|
# http://www.matthewflickinger.com/lab/whatsinagif/bits_and_bytes.asp
|
||
|
|
|
||
|
|
version = b"87a"
|
||
|
|
for extensionKey in ["transparency", "duration", "loop", "comment"]:
|
||
|
|
if info and extensionKey in info:
|
||
|
|
if ((extensionKey == "duration" and info[extensionKey] == 0) or
|
||
|
|
(extensionKey == "comment" and not (1 <= len(info[extensionKey]) <= 255))):
|
||
|
|
continue
|
||
|
|
version = b"89a"
|
||
|
|
break
|
||
|
|
else:
|
||
|
|
if im.info.get("version") == b"89a":
|
||
|
|
version = b"89a"
|
||
|
|
|
||
|
|
palette_bytes = _get_palette_bytes(im)
|
||
|
|
color_table_size = _get_color_table_size(palette_bytes)
|
||
|
|
|
||
|
|
background = info["background"] if "background" in info else 0
|
||
|
|
|
||
|
|
return [
|
||
|
|
b"GIF"+version + # signature + version
|
||
|
|
o16(im.size[0]) + # canvas width
|
||
|
|
o16(im.size[1]), # canvas height
|
||
|
|
|
||
|
|
# Logical Screen Descriptor
|
||
|
|
# size of global color table + global color table flag
|
||
|
|
o8(color_table_size + 128), # packed fields
|
||
|
|
# background + reserved/aspect
|
||
|
|
o8(background) + o8(0),
|
||
|
|
|
||
|
|
# Global Color Table
|
||
|
|
_get_header_palette(palette_bytes)
|
||
|
|
]
|
||
|
|
|
||
|
|
|
||
|
|
def _write_frame_data(fp, im_frame, offset, params):
|
||
|
|
try:
|
||
|
|
im_frame.encoderinfo = params
|
||
|
|
|
||
|
|
# local image header
|
||
|
|
_write_local_header(fp, im_frame, offset, 0)
|
||
|
|
|
||
|
|
ImageFile._save(im_frame, fp, [("gif", (0, 0)+im_frame.size, 0,
|
||
|
|
RAWMODE[im_frame.mode])])
|
||
|
|
|
||
|
|
fp.write(b"\0") # end of image data
|
||
|
|
finally:
|
||
|
|
del im_frame.encoderinfo
|
||
|
|
|
||
|
|
# --------------------------------------------------------------------
|
||
|
|
# Legacy GIF utilities
|
||
|
|
|
||
|
|
|
||
|
|
def getheader(im, palette=None, info=None):
|
||
|
|
"""
|
||
|
|
Legacy Method to get Gif data from image.
|
||
|
|
|
||
|
|
Warning:: May modify image data.
|
||
|
|
|
||
|
|
:param im: Image object
|
||
|
|
:param palette: bytes object containing the source palette, or ....
|
||
|
|
:param info: encoderinfo
|
||
|
|
:returns: tuple of(list of header items, optimized palette)
|
||
|
|
|
||
|
|
"""
|
||
|
|
used_palette_colors = _get_optimize(im, info)
|
||
|
|
|
||
|
|
if info is None:
|
||
|
|
info = {}
|
||
|
|
|
||
|
|
if "background" not in info and "background" in im.info:
|
||
|
|
info["background"] = im.info["background"]
|
||
|
|
|
||
|
|
im_mod = _normalize_palette(im, palette, info)
|
||
|
|
im.palette = im_mod.palette
|
||
|
|
im.im = im_mod.im
|
||
|
|
header = _get_global_header(im, info)
|
||
|
|
|
||
|
|
return header, used_palette_colors
|
||
|
|
|
||
|
|
|
||
|
|
# To specify duration, add the time in milliseconds to getdata(),
|
||
|
|
# e.g. getdata(im_frame, duration=1000)
|
||
|
|
def getdata(im, offset=(0, 0), **params):
|
||
|
|
"""
|
||
|
|
Legacy Method
|
||
|
|
|
||
|
|
Return a list of strings representing this image.
|
||
|
|
The first string is a local image header, the rest contains
|
||
|
|
encoded image data.
|
||
|
|
|
||
|
|
:param im: Image object
|
||
|
|
:param offset: Tuple of (x, y) pixels. Defaults to (0,0)
|
||
|
|
:param \\**params: E.g. duration or other encoder info parameters
|
||
|
|
:returns: List of Bytes containing gif encoded frame data
|
||
|
|
|
||
|
|
"""
|
||
|
|
class Collector(object):
|
||
|
|
data = []
|
||
|
|
|
||
|
|
def write(self, data):
|
||
|
|
self.data.append(data)
|
||
|
|
|
||
|
|
im.load() # make sure raster data is available
|
||
|
|
|
||
|
|
fp = Collector()
|
||
|
|
|
||
|
|
_write_frame_data(fp, im, offset, params)
|
||
|
|
|
||
|
|
return fp.data
|
||
|
|
|
||
|
|
|
||
|
|
# --------------------------------------------------------------------
|
||
|
|
# Registry
|
||
|
|
|
||
|
|
Image.register_open(GifImageFile.format, GifImageFile, _accept)
|
||
|
|
Image.register_save(GifImageFile.format, _save)
|
||
|
|
Image.register_save_all(GifImageFile.format, _save_all)
|
||
|
|
Image.register_extension(GifImageFile.format, ".gif")
|
||
|
|
Image.register_mime(GifImageFile.format, "image/gif")
|
||
|
|
|
||
|
|
#
|
||
|
|
# Uncomment the following line if you wish to use NETPBM/PBMPLUS
|
||
|
|
# instead of the built-in "uncompressed" GIF encoder
|
||
|
|
|
||
|
|
# Image.register_save(GifImageFile.format, _save_netpbm)
|