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| # | |
| # 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 __future__ import annotations | |
| import itertools | |
| import math | |
| import os | |
| import subprocess | |
| from enum import IntEnum | |
| from . import ( | |
| Image, | |
| ImageChops, | |
| ImageFile, | |
| ImageMath, | |
| ImageOps, | |
| ImagePalette, | |
| ImageSequence, | |
| ) | |
| from ._binary import i16le as i16 | |
| from ._binary import o8 | |
| from ._binary import o16le as o16 | |
| class LoadingStrategy(IntEnum): | |
| """.. versionadded:: 9.1.0""" | |
| RGB_AFTER_FIRST = 0 | |
| RGB_AFTER_DIFFERENT_PALETTE_ONLY = 1 | |
| RGB_ALWAYS = 2 | |
| #: .. versionadded:: 9.1.0 | |
| LOADING_STRATEGY = LoadingStrategy.RGB_AFTER_FIRST | |
| # -------------------------------------------------------------------- | |
| # 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 s[0]: | |
| return self.fp.read(s[0]) | |
| return None | |
| def _is_palette_needed(self, p): | |
| for i in range(0, len(p), 3): | |
| if not (i // 3 == p[i] == p[i + 1] == p[i + 2]): | |
| return True | |
| return False | |
| def _open(self): | |
| # Screen | |
| s = self.fp.read(13) | |
| if not _accept(s): | |
| msg = "not a GIF file" | |
| raise SyntaxError(msg) | |
| self.info["version"] = s[:6] | |
| self._size = i16(s, 6), i16(s, 8) | |
| self.tile = [] | |
| flags = s[10] | |
| bits = (flags & 7) + 1 | |
| if flags & 128: | |
| # get global palette | |
| self.info["background"] = s[11] | |
| # check if palette contains colour indices | |
| p = self.fp.read(3 << bits) | |
| if self._is_palette_needed(p): | |
| p = ImagePalette.raw("RGB", p) | |
| self.global_palette = self.palette = p | |
| 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 | |
| def n_frames(self): | |
| if self._n_frames is None: | |
| current = self.tell() | |
| try: | |
| while True: | |
| self._seek(self.tell() + 1, False) | |
| except EOFError: | |
| self._n_frames = self.tell() + 1 | |
| self.seek(current) | |
| return self._n_frames | |
| 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() | |
| if current: | |
| self._is_animated = True | |
| else: | |
| try: | |
| self._seek(1, False) | |
| 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.im = None | |
| self._seek(0) | |
| last_frame = self.__frame | |
| for f in range(self.__frame + 1, frame + 1): | |
| try: | |
| self._seek(f) | |
| except EOFError as e: | |
| self.seek(last_frame) | |
| msg = "no more images in GIF file" | |
| raise EOFError(msg) from e | |
| def _seek(self, frame, update_image=True): | |
| if frame == 0: | |
| # rewind | |
| self.__offset = 0 | |
| self.dispose = None | |
| self.__frame = -1 | |
| self._fp.seek(self.__rewind) | |
| self.disposal_method = 0 | |
| if "comment" in self.info: | |
| del self.info["comment"] | |
| else: | |
| # ensure that the previous frame was loaded | |
| if self.tile and update_image: | |
| self.load() | |
| if frame != self.__frame + 1: | |
| msg = f"cannot seek to frame {frame}" | |
| raise ValueError(msg) | |
| self.fp = self._fp | |
| if self.__offset: | |
| # backup to last frame | |
| self.fp.seek(self.__offset) | |
| while self.data(): | |
| pass | |
| self.__offset = 0 | |
| s = self.fp.read(1) | |
| if not s or s == b";": | |
| msg = "no more images in GIF file" | |
| raise EOFError(msg) | |
| palette = None | |
| info = {} | |
| frame_transparency = None | |
| interlace = None | |
| frame_dispose_extent = None | |
| while True: | |
| if not s: | |
| 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 s[0] == 249: | |
| # | |
| # graphic control extension | |
| # | |
| flags = block[0] | |
| if flags & 1: | |
| frame_transparency = block[3] | |
| info["duration"] = i16(block, 1) * 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 s[0] == 254: | |
| # | |
| # comment extension | |
| # | |
| comment = b"" | |
| # Read this comment block | |
| while block: | |
| comment += block | |
| block = self.data() | |
| if "comment" in info: | |
| # If multiple comment blocks in frame, separate with \n | |
| info["comment"] += b"\n" + comment | |
| else: | |
| info["comment"] = comment | |
| s = None | |
| continue | |
| elif s[0] == 255 and frame == 0: | |
| # | |
| # application extension | |
| # | |
| info["extension"] = block, self.fp.tell() | |
| if block[:11] == b"NETSCAPE2.0": | |
| block = self.data() | |
| if len(block) >= 3 and block[0] == 1: | |
| self.info["loop"] = i16(block, 1) | |
| 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) | |
| if (x1 > self.size[0] or y1 > self.size[1]) and update_image: | |
| self._size = max(x1, self.size[0]), max(y1, self.size[1]) | |
| Image._decompression_bomb_check(self._size) | |
| frame_dispose_extent = x0, y0, x1, y1 | |
| flags = s[8] | |
| interlace = (flags & 64) != 0 | |
| if flags & 128: | |
| bits = (flags & 7) + 1 | |
| p = self.fp.read(3 << bits) | |
| if self._is_palette_needed(p): | |
| palette = ImagePalette.raw("RGB", p) | |
| else: | |
| palette = False | |
| # image data | |
| bits = self.fp.read(1)[0] | |
| self.__offset = self.fp.tell() | |
| break | |
| s = None | |
| if interlace is None: | |
| msg = "image not found in GIF frame" | |
| raise EOFError(msg) | |
| self.__frame = frame | |
| if not update_image: | |
| return | |
| self.tile = [] | |
| if self.dispose: | |
| self.im.paste(self.dispose, self.dispose_extent) | |
| self._frame_palette = palette if palette is not None else self.global_palette | |
| self._frame_transparency = frame_transparency | |
| if frame == 0: | |
| if self._frame_palette: | |
| if LOADING_STRATEGY == LoadingStrategy.RGB_ALWAYS: | |
| self._mode = "RGBA" if frame_transparency is not None else "RGB" | |
| else: | |
| self._mode = "P" | |
| else: | |
| self._mode = "L" | |
| if not palette and self.global_palette: | |
| from copy import copy | |
| palette = copy(self.global_palette) | |
| self.palette = palette | |
| else: | |
| if self.mode == "P": | |
| if ( | |
| LOADING_STRATEGY != LoadingStrategy.RGB_AFTER_DIFFERENT_PALETTE_ONLY | |
| or palette | |
| ): | |
| self.pyaccess = None | |
| if "transparency" in self.info: | |
| self.im.putpalettealpha(self.info["transparency"], 0) | |
| self.im = self.im.convert("RGBA", Image.Dither.FLOYDSTEINBERG) | |
| self._mode = "RGBA" | |
| del self.info["transparency"] | |
| else: | |
| self._mode = "RGB" | |
| self.im = self.im.convert("RGB", Image.Dither.FLOYDSTEINBERG) | |
| def _rgb(color): | |
| if self._frame_palette: | |
| if color * 3 + 3 > len(self._frame_palette.palette): | |
| color = 0 | |
| color = tuple(self._frame_palette.palette[color * 3 : color * 3 + 3]) | |
| else: | |
| color = (color, color, color) | |
| return color | |
| self.dispose_extent = frame_dispose_extent | |
| try: | |
| if self.disposal_method < 2: | |
| # do not dispose or none specified | |
| self.dispose = None | |
| elif self.disposal_method == 2: | |
| # replace with background colour | |
| # only dispose the extent in this frame | |
| x0, y0, x1, y1 = self.dispose_extent | |
| dispose_size = (x1 - x0, y1 - y0) | |
| Image._decompression_bomb_check(dispose_size) | |
| # by convention, attempt to use transparency first | |
| dispose_mode = "P" | |
| color = self.info.get("transparency", frame_transparency) | |
| if color is not None: | |
| if self.mode in ("RGB", "RGBA"): | |
| dispose_mode = "RGBA" | |
| color = _rgb(color) + (0,) | |
| else: | |
| color = self.info.get("background", 0) | |
| if self.mode in ("RGB", "RGBA"): | |
| dispose_mode = "RGB" | |
| color = _rgb(color) | |
| self.dispose = Image.core.fill(dispose_mode, dispose_size, color) | |
| else: | |
| # replace with previous contents | |
| if self.im is not None: | |
| # only dispose the extent in this frame | |
| self.dispose = self._crop(self.im, self.dispose_extent) | |
| elif frame_transparency is not None: | |
| x0, y0, x1, y1 = self.dispose_extent | |
| dispose_size = (x1 - x0, y1 - y0) | |
| Image._decompression_bomb_check(dispose_size) | |
| dispose_mode = "P" | |
| color = frame_transparency | |
| if self.mode in ("RGB", "RGBA"): | |
| dispose_mode = "RGBA" | |
| color = _rgb(frame_transparency) + (0,) | |
| self.dispose = Image.core.fill(dispose_mode, dispose_size, color) | |
| except AttributeError: | |
| pass | |
| if interlace is not None: | |
| transparency = -1 | |
| if frame_transparency is not None: | |
| if frame == 0: | |
| if LOADING_STRATEGY != LoadingStrategy.RGB_ALWAYS: | |
| self.info["transparency"] = frame_transparency | |
| elif self.mode not in ("RGB", "RGBA"): | |
| transparency = frame_transparency | |
| self.tile = [ | |
| ( | |
| "gif", | |
| (x0, y0, x1, y1), | |
| self.__offset, | |
| (bits, interlace, transparency), | |
| ) | |
| ] | |
| if info.get("comment"): | |
| self.info["comment"] = info["comment"] | |
| for k in ["duration", "extension"]: | |
| if k in info: | |
| self.info[k] = info[k] | |
| elif k in self.info: | |
| del self.info[k] | |
| def load_prepare(self): | |
| temp_mode = "P" if self._frame_palette else "L" | |
| self._prev_im = None | |
| if self.__frame == 0: | |
| if self._frame_transparency is not None: | |
| self.im = Image.core.fill( | |
| temp_mode, self.size, self._frame_transparency | |
| ) | |
| elif self.mode in ("RGB", "RGBA"): | |
| self._prev_im = self.im | |
| if self._frame_palette: | |
| self.im = Image.core.fill("P", self.size, self._frame_transparency or 0) | |
| self.im.putpalette(*self._frame_palette.getdata()) | |
| else: | |
| self.im = None | |
| self._mode = temp_mode | |
| self._frame_palette = None | |
| super().load_prepare() | |
| def load_end(self): | |
| if self.__frame == 0: | |
| if self.mode == "P" and LOADING_STRATEGY == LoadingStrategy.RGB_ALWAYS: | |
| if self._frame_transparency is not None: | |
| self.im.putpalettealpha(self._frame_transparency, 0) | |
| self._mode = "RGBA" | |
| else: | |
| self._mode = "RGB" | |
| self.im = self.im.convert(self.mode, Image.Dither.FLOYDSTEINBERG) | |
| return | |
| if not self._prev_im: | |
| return | |
| if self._frame_transparency is not None: | |
| self.im.putpalettealpha(self._frame_transparency, 0) | |
| frame_im = self.im.convert("RGBA") | |
| else: | |
| frame_im = self.im.convert("RGB") | |
| frame_im = self._crop(frame_im, self.dispose_extent) | |
| self.im = self._prev_im | |
| self._mode = self.im.mode | |
| if frame_im.mode == "RGBA": | |
| self.im.paste(frame_im, self.dispose_extent, frame_im) | |
| else: | |
| self.im.paste(frame_im, self.dispose_extent) | |
| def tell(self): | |
| return self.__frame | |
| # -------------------------------------------------------------------- | |
| # Write GIF files | |
| RAWMODE = {"1": "L", "L": "L", "P": "P"} | |
| def _normalize_mode(im): | |
| """ | |
| 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. | |
| :param im: Image object | |
| :returns: Image object | |
| """ | |
| if im.mode in RAWMODE: | |
| im.load() | |
| return im | |
| if Image.getmodebase(im.mode) == "RGB": | |
| im = im.convert("P", palette=Image.Palette.ADAPTIVE) | |
| if im.palette.mode == "RGBA": | |
| for rgba in im.palette.colors: | |
| if rgba[3] == 0: | |
| im.info["transparency"] = im.palette.colors[rgba] | |
| break | |
| return im | |
| 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(palette.palette) | |
| 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) | |
| if palette: | |
| used_palette_colors = [] | |
| for i in range(0, len(source_palette), 3): | |
| source_color = tuple(source_palette[i : i + 3]) | |
| index = im.palette.colors.get(source_color) | |
| if index in used_palette_colors: | |
| index = None | |
| used_palette_colors.append(index) | |
| for i, index in enumerate(used_palette_colors): | |
| if index is None: | |
| for j in range(len(used_palette_colors)): | |
| if j not in used_palette_colors: | |
| used_palette_colors[i] = j | |
| break | |
| im = im.remap_palette(used_palette_colors) | |
| else: | |
| used_palette_colors = _get_optimize(im, info) | |
| if used_palette_colors is not None: | |
| im = im.remap_palette(used_palette_colors, source_palette) | |
| if "transparency" in info: | |
| try: | |
| info["transparency"] = used_palette_colors.index( | |
| info["transparency"] | |
| ) | |
| except ValueError: | |
| del info["transparency"] | |
| return im | |
| im.palette.palette = source_palette | |
| return im | |
| def _write_single_frame(im, fp, palette): | |
| im_out = _normalize_mode(im) | |
| for k, v in im_out.info.items(): | |
| im.encoderinfo.setdefault(k, v) | |
| 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 _getbbox(base_im, im_frame): | |
| if _get_palette_bytes(im_frame) != _get_palette_bytes(base_im): | |
| im_frame = im_frame.convert("RGBA") | |
| base_im = base_im.convert("RGBA") | |
| delta = ImageChops.subtract_modulo(im_frame, base_im) | |
| return delta, delta.getbbox(alpha_only=False) | |
| def _write_multiple_frames(im, fp, palette): | |
| duration = im.encoderinfo.get("duration") | |
| disposal = im.encoderinfo.get("disposal", im.info.get("disposal")) | |
| im_frames = [] | |
| previous_im = None | |
| frame_count = 0 | |
| background_im = None | |
| 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()) | |
| if frame_count == 0: | |
| for k, v in im_frame.info.items(): | |
| if k == "transparency": | |
| continue | |
| im.encoderinfo.setdefault(k, v) | |
| encoderinfo = im.encoderinfo.copy() | |
| if "transparency" in im_frame.info: | |
| encoderinfo.setdefault("transparency", im_frame.info["transparency"]) | |
| im_frame = _normalize_palette(im_frame, palette, encoderinfo) | |
| if isinstance(duration, (list, tuple)): | |
| encoderinfo["duration"] = duration[frame_count] | |
| elif duration is None and "duration" in im_frame.info: | |
| encoderinfo["duration"] = im_frame.info["duration"] | |
| if isinstance(disposal, (list, tuple)): | |
| encoderinfo["disposal"] = disposal[frame_count] | |
| frame_count += 1 | |
| diff_frame = None | |
| if im_frames: | |
| # delta frame | |
| delta, bbox = _getbbox(previous_im, im_frame) | |
| if not bbox: | |
| # This frame is identical to the previous frame | |
| if encoderinfo.get("duration"): | |
| im_frames[-1]["encoderinfo"]["duration"] += encoderinfo[ | |
| "duration" | |
| ] | |
| continue | |
| if im_frames[-1]["encoderinfo"].get("disposal") == 2: | |
| if background_im is None: | |
| color = im.encoderinfo.get( | |
| "transparency", im.info.get("transparency", (0, 0, 0)) | |
| ) | |
| background = _get_background(im_frame, color) | |
| background_im = Image.new("P", im_frame.size, background) | |
| background_im.putpalette(im_frames[0]["im"].palette) | |
| bbox = _getbbox(background_im, im_frame)[1] | |
| elif encoderinfo.get("optimize") and im_frame.mode != "1": | |
| if "transparency" not in encoderinfo: | |
| try: | |
| encoderinfo["transparency"] = ( | |
| im_frame.palette._new_color_index(im_frame) | |
| ) | |
| except ValueError: | |
| pass | |
| if "transparency" in encoderinfo: | |
| # When the delta is zero, fill the image with transparency | |
| diff_frame = im_frame.copy() | |
| fill = Image.new("P", delta.size, encoderinfo["transparency"]) | |
| if delta.mode == "RGBA": | |
| r, g, b, a = delta.split() | |
| mask = ImageMath.lambda_eval( | |
| lambda args: args["convert"]( | |
| args["max"]( | |
| args["max"]( | |
| args["max"](args["r"], args["g"]), args["b"] | |
| ), | |
| args["a"], | |
| ) | |
| * 255, | |
| "1", | |
| ), | |
| r=r, | |
| g=g, | |
| b=b, | |
| a=a, | |
| ) | |
| else: | |
| if delta.mode == "P": | |
| # Convert to L without considering palette | |
| delta_l = Image.new("L", delta.size) | |
| delta_l.putdata(delta.getdata()) | |
| delta = delta_l | |
| mask = ImageMath.lambda_eval( | |
| lambda args: args["convert"](args["im"] * 255, "1"), | |
| im=delta, | |
| ) | |
| diff_frame.paste(fill, mask=ImageOps.invert(mask)) | |
| else: | |
| bbox = None | |
| previous_im = im_frame | |
| im_frames.append( | |
| {"im": diff_frame or im_frame, "bbox": bbox, "encoderinfo": encoderinfo} | |
| ) | |
| if len(im_frames) == 1: | |
| if "duration" in im.encoderinfo: | |
| # Since multiple frames will not be written, use the combined duration | |
| im.encoderinfo["duration"] = im_frames[0]["encoderinfo"]["duration"] | |
| return | |
| 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 | |
| if not palette: | |
| 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): | |
| # header | |
| if "palette" in im.encoderinfo or "palette" in im.info: | |
| palette = im.encoderinfo.get("palette", im.info.get("palette")) | |
| else: | |
| palette = None | |
| im.encoderinfo.setdefault("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): | |
| try: | |
| transparency = im.encoderinfo["transparency"] | |
| except KeyError: | |
| transparency = None | |
| if "duration" in im.encoderinfo: | |
| duration = int(im.encoderinfo["duration"] / 10) | |
| else: | |
| duration = 0 | |
| disposal = int(im.encoderinfo.get("disposal", 0)) | |
| if transparency is not None or duration != 0 or disposal: | |
| packed_flag = 1 if transparency is not None else 0 | |
| packed_flag |= disposal << 2 | |
| fp.write( | |
| b"!" | |
| + o8(249) # extension intro | |
| + o8(4) # length | |
| + o8(packed_flag) # packed fields | |
| + o16(duration) # duration | |
| + o8(transparency or 0) # transparency index | |
| + o8(0) | |
| ) | |
| include_color_table = im.encoderinfo.get("include_color_table") | |
| if include_color_table: | |
| 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. | |
| tempfile = im._dump() | |
| try: | |
| with open(filename, "wb") as f: | |
| if im.mode != "RGB": | |
| subprocess.check_call( | |
| ["ppmtogif", tempfile], stdout=f, stderr=subprocess.DEVNULL | |
| ) | |
| else: | |
| # Pipe ppmquant output into ppmtogif | |
| # "ppmquant 256 %s | ppmtogif > %s" % (tempfile, filename) | |
| quant_cmd = ["ppmquant", "256", tempfile] | |
| togif_cmd = ["ppmtogif"] | |
| quant_proc = subprocess.Popen( | |
| quant_cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL | |
| ) | |
| togif_proc = subprocess.Popen( | |
| togif_cmd, | |
| stdin=quant_proc.stdout, | |
| stdout=f, | |
| stderr=subprocess.DEVNULL, | |
| ) | |
| # Allow ppmquant to receive SIGPIPE if ppmtogif exits | |
| quant_proc.stdout.close() | |
| retcode = quant_proc.wait() | |
| if retcode: | |
| raise subprocess.CalledProcessError(retcode, quant_cmd) | |
| retcode = togif_proc.wait() | |
| if retcode: | |
| raise subprocess.CalledProcessError(retcode, togif_cmd) | |
| finally: | |
| try: | |
| os.unlink(tempfile) | |
| 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"): | |
| # 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 max(used_palette_colors) >= len(used_palette_colors): | |
| return used_palette_colors | |
| num_palette_colors = len(im.palette.palette) // Image.getmodebands( | |
| im.palette.mode | |
| ) | |
| current_palette_size = 1 << (num_palette_colors - 1).bit_length() | |
| if ( | |
| # check that the palette would become smaller when saved | |
| len(used_palette_colors) <= current_palette_size // 2 | |
| # check that the palette is not already the smallest possible size | |
| and current_palette_size > 2 | |
| ): | |
| return used_palette_colors | |
| def _get_color_table_size(palette_bytes): | |
| # calculate the palette size for the header | |
| if not palette_bytes: | |
| return 0 | |
| elif len(palette_bytes) < 9: | |
| return 1 | |
| else: | |
| return math.ceil(math.log(len(palette_bytes) // 3, 2)) - 1 | |
| 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 if im.palette else b"" | |
| def _get_background(im, info_background): | |
| background = 0 | |
| if info_background: | |
| if isinstance(info_background, tuple): | |
| # WebPImagePlugin stores an RGBA value in info["background"] | |
| # So it must be converted to the same format as GifImagePlugin's | |
| # info["background"] - a global color table index | |
| try: | |
| background = im.palette.getcolor(info_background, im) | |
| except ValueError as e: | |
| if str(e) not in ( | |
| # If all 256 colors are in use, | |
| # then there is no need for the background color | |
| "cannot allocate more than 256 colors", | |
| # Ignore non-opaque WebP background | |
| "cannot add non-opaque RGBA color to RGB palette", | |
| ): | |
| raise | |
| else: | |
| background = info_background | |
| return background | |
| def _get_global_header(im, info): | |
| """Return a list of strings representing a GIF header""" | |
| # Header Block | |
| # https://www.matthewflickinger.com/lab/whatsinagif/bits_and_bytes.asp | |
| version = b"87a" | |
| if im.info.get("version") == b"89a" or ( | |
| info | |
| and ( | |
| "transparency" in info | |
| or info.get("loop") is not None | |
| or info.get("duration") | |
| or info.get("comment") | |
| ) | |
| ): | |
| version = b"89a" | |
| background = _get_background(im, info.get("background")) | |
| palette_bytes = _get_palette_bytes(im) | |
| color_table_size = _get_color_table_size(palette_bytes) | |
| header = [ | |
| b"GIF" # signature | |
| + version # 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), | |
| ] | |
| if info.get("loop") is not None: | |
| header.append( | |
| b"!" | |
| + o8(255) # extension intro | |
| + o8(11) | |
| + b"NETSCAPE2.0" | |
| + o8(3) | |
| + o8(1) | |
| + o16(info["loop"]) # number of loops | |
| + o8(0) | |
| ) | |
| if info.get("comment"): | |
| comment_block = b"!" + o8(254) # extension intro | |
| comment = info["comment"] | |
| if isinstance(comment, str): | |
| comment = comment.encode() | |
| for i in range(0, len(comment), 255): | |
| subblock = comment[i : i + 255] | |
| comment_block += o8(len(subblock)) + subblock | |
| comment_block += o8(0) | |
| header.append(comment_block) | |
| return header | |
| 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 | |
| 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. | |
| To specify duration, add the time in milliseconds, | |
| e.g. ``getdata(im_frame, duration=1000)`` | |
| :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: | |
| 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) | |