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authorS. Solomon Darnell2025-03-28 21:52:21 -0500
committerS. Solomon Darnell2025-03-28 21:52:21 -0500
commit4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch)
treeee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/pypdf/_xobj_image_helpers.py
parentcc961e04ba734dd72309fb548a2f97d67d578813 (diff)
downloadgn-ai-master.tar.gz
two version of R2R are here HEAD master
Diffstat (limited to '.venv/lib/python3.12/site-packages/pypdf/_xobj_image_helpers.py')
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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