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"""Code in here is only used by pypdf.filters._xobj_to_image"""
import sys
from io import BytesIO
from typing import Any, List, Tuple, Union, cast
from ._utils import check_if_whitespace_only, logger_warning
from .constants import ColorSpaces
from .errors import PdfReadError
from .generic import (
ArrayObject,
DecodedStreamObject,
EncodedStreamObject,
IndirectObject,
NullObject,
)
if sys.version_info[:2] >= (3, 8):
from typing import Literal
else:
# PEP 586 introduced typing.Literal with Python 3.8
# For older Python versions, the backport typing_extensions is necessary:
from typing_extensions import Literal
if sys.version_info[:2] >= (3, 10):
from typing import TypeAlias
else:
from typing_extensions import TypeAlias
try:
from PIL import Image, UnidentifiedImageError # noqa: F401
except ImportError:
raise ImportError(
"pillow is required to do image extraction. "
"It can be installed via 'pip install pypdf[image]'"
)
mode_str_type: TypeAlias = Literal[
"", "1", "RGB", "2bits", "4bits", "P", "L", "RGBA", "CMYK"
]
MAX_IMAGE_MODE_NESTING_DEPTH: int = 10
def _get_imagemode(
color_space: Union[str, List[Any], Any],
color_components: int,
prev_mode: mode_str_type,
depth: int = 0,
) -> Tuple[mode_str_type, bool]:
"""
Returns
Image mode not taking into account mask(transparency)
ColorInversion is required (like for some DeviceCMYK)
"""
if depth > MAX_IMAGE_MODE_NESTING_DEPTH:
raise PdfReadError(
"Color spaces nested too deep. If required, consider increasing MAX_IMAGE_MODE_NESTING_DEPTH."
)
if isinstance(color_space, NullObject):
return "", False
if isinstance(color_space, str):
pass
elif not isinstance(color_space, list):
raise PdfReadError(
"Cannot interpret colorspace", color_space
) # pragma: no cover
elif color_space[0].startswith("/Cal"): # /CalRGB and /CalGray
color_space = "/Device" + color_space[0][4:]
elif color_space[0] == "/ICCBased":
icc_profile = color_space[1].get_object()
color_components = cast(int, icc_profile["/N"])
color_space = icc_profile.get("/Alternate", "")
elif color_space[0] == "/Indexed":
color_space = color_space[1].get_object()
mode2, invert_color = _get_imagemode(
color_space, color_components, prev_mode, depth + 1
)
if mode2 in ("RGB", "CMYK"):
mode2 = "P"
return mode2, invert_color
elif color_space[0] == "/Separation":
color_space = color_space[2]
if isinstance(color_space, IndirectObject):
color_space = color_space.get_object()
mode2, invert_color = _get_imagemode(
color_space, color_components, prev_mode, depth + 1
)
return mode2, True
elif color_space[0] == "/DeviceN":
original_color_space = color_space
color_components = len(color_space[1])
color_space = color_space[2]
if isinstance(color_space, IndirectObject): # pragma: no cover
color_space = color_space.get_object()
if color_space == "/DeviceCMYK" and color_components == 1:
if original_color_space[1][0] != "/Black":
logger_warning(
f"Color {original_color_space[1][0]} converted to Gray. Please share PDF with pypdf dev team",
__name__,
)
return "L", True
mode2, invert_color = _get_imagemode(
color_space, color_components, prev_mode, depth + 1
)
return mode2, invert_color
mode_map = {
"1bit": "1", # pos [0] will be used for 1 bit
"/DeviceGray": "L", # must be in pos [1]
"palette": "P", # must be in pos [2] for color_components align.
"/DeviceRGB": "RGB", # must be in pos [3]
"/DeviceCMYK": "CMYK", # must be in pos [4]
"2bit": "2bits", # 2 bits images
"4bit": "4bits", # 4 bits
}
mode: mode_str_type = (
mode_map.get(color_space) # type: ignore
or list(mode_map.values())[color_components]
or prev_mode
)
return mode, mode == "CMYK"
def bits2byte(data: bytes, size: Tuple[int, int], bits: int) -> bytes:
mask = (1 << bits) - 1
nbuff = bytearray(size[0] * size[1])
by = 0
bit = 8 - bits
for y in range(size[1]):
if (bit != 0) and (bit != 8 - bits):
by += 1
bit = 8 - bits
for x in range(size[0]):
nbuff[y * size[0] + x] = (data[by] >> bit) & mask
bit -= bits
if bit < 0:
by += 1
bit = 8 - bits
return bytes(nbuff)
def _extended_image_frombytes(
mode: str, size: Tuple[int, int], data: bytes
) -> Image.Image:
try:
img = Image.frombytes(mode, size, data)
except ValueError as exc:
nb_pix = size[0] * size[1]
if len(data) % nb_pix != 0:
raise exc
k = nb_pix * len(mode) / len(data)
data = b"".join([bytes((x,) * int(k)) for x in data])
img = Image.frombytes(mode, size, data)
return img
def _handle_flate(
size: Tuple[int, int],
data: bytes,
mode: mode_str_type,
color_space: str,
colors: int,
obj_as_text: str,
) -> Tuple[Image.Image, str, str, bool]:
"""
Process image encoded in flateEncode
Returns img, image_format, extension, color inversion
"""
extension = ".png" # mime_type = "image/png"
image_format = "PNG"
lookup: Any
base: Any
hival: Any
if isinstance(color_space, ArrayObject) and color_space[0] == "/Indexed":
color_space, base, hival, lookup = (value.get_object() for value in color_space)
if mode == "2bits":
mode = "P"
data = bits2byte(data, size, 2)
elif mode == "4bits":
mode = "P"
data = bits2byte(data, size, 4)
img = _extended_image_frombytes(mode, size, data)
if color_space == "/Indexed":
from .generic import TextStringObject
if isinstance(lookup, (EncodedStreamObject, DecodedStreamObject)):
lookup = lookup.get_data()
if isinstance(lookup, TextStringObject):
lookup = lookup.original_bytes
if isinstance(lookup, str):
lookup = lookup.encode()
try:
nb, conv, mode = { # type: ignore
"1": (0, "", ""),
"L": (1, "P", "L"),
"P": (0, "", ""),
"RGB": (3, "P", "RGB"),
"CMYK": (4, "P", "CMYK"),
}[_get_imagemode(base, 0, "")[0]]
except KeyError: # pragma: no cover
logger_warning(
f"Base {base} not coded please share the pdf file with pypdf dev team",
__name__,
)
lookup = None
else:
if img.mode == "1":
# Two values ("high" and "low").
expected_count = 2 * nb
if len(lookup) != expected_count:
if len(lookup) < expected_count:
raise PdfReadError(
f"Not enough lookup values: Expected {expected_count}, got {len(lookup)}."
)
if not check_if_whitespace_only(lookup[expected_count:]):
raise PdfReadError(
f"Too many lookup values: Expected {expected_count}, got {len(lookup)}."
)
lookup = lookup[:expected_count]
colors_arr = [lookup[:nb], lookup[nb:]]
arr = b"".join(
[
b"".join(
[
colors_arr[1 if img.getpixel((x, y)) > 127 else 0]
for x in range(img.size[0])
]
)
for y in range(img.size[1])
]
)
img = Image.frombytes(mode, img.size, arr)
else:
img = img.convert(conv)
if len(lookup) != (hival + 1) * nb:
logger_warning(f"Invalid Lookup Table in {obj_as_text}", __name__)
lookup = None
elif mode == "L":
# gray lookup does not work : it is converted to a similar RGB lookup
lookup = b"".join([bytes([b, b, b]) for b in lookup])
mode = "RGB"
# TODO : cf https://github.com/py-pdf/pypdf/pull/2039
# this is a work around until PIL is able to process CMYK images
elif mode == "CMYK":
_rgb = []
for _c, _m, _y, _k in (
lookup[n : n + 4] for n in range(0, 4 * (len(lookup) // 4), 4)
):
_r = int(255 * (1 - _c / 255) * (1 - _k / 255))
_g = int(255 * (1 - _m / 255) * (1 - _k / 255))
_b = int(255 * (1 - _y / 255) * (1 - _k / 255))
_rgb.append(bytes((_r, _g, _b)))
lookup = b"".join(_rgb)
mode = "RGB"
if lookup is not None:
img.putpalette(lookup, rawmode=mode)
img = img.convert("L" if base == ColorSpaces.DEVICE_GRAY else "RGB")
elif not isinstance(color_space, NullObject) and color_space[0] == "/ICCBased":
# see Table 66 - Additional Entries Specific to an ICC Profile
# Stream Dictionary
mode2 = _get_imagemode(color_space, colors, mode)[0]
if mode != mode2:
img = Image.frombytes(mode2, size, data) # reloaded as mode may have change
if mode == "CMYK":
extension = ".tif"
image_format = "TIFF"
return img, image_format, extension, False
def _handle_jpx(
size: Tuple[int, int],
data: bytes,
mode: mode_str_type,
color_space: str,
colors: int,
) -> Tuple[Image.Image, str, str, bool]:
"""
Process image encoded in flateEncode
Returns img, image_format, extension, inversion
"""
extension = ".jp2" # mime_type = "image/x-jp2"
img1 = Image.open(BytesIO(data), formats=("JPEG2000",))
mode, invert_color = _get_imagemode(color_space, colors, mode)
if mode == "":
mode = cast(mode_str_type, img1.mode)
invert_color = mode in ("CMYK",)
if img1.mode == "RGBA" and mode == "RGB":
mode = "RGBA"
# we need to convert to the good mode
if img1.mode == mode or {img1.mode, mode} == {"L", "P"}: # compare (unordered) sets
# L,P are indexed modes which should not be changed.
img = img1
elif {img1.mode, mode} == {"RGBA", "CMYK"}:
# RGBA / CMYK are 4bytes encoding where
# the encoding should be corrected
img = Image.frombytes(mode, img1.size, img1.tobytes())
else: # pragma: no cover
img = img1.convert(mode)
# for CMYK conversion :
# https://stcom/questions/38855022/conversion-from-cmyk-to-rgb-with-pillow-is-different-from-that-of-photoshop
# not implemented for the moment as I need to get properly the ICC
if img.mode == "CMYK":
img = img.convert("RGB")
image_format = "JPEG2000"
return img, image_format, extension, invert_color
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