1050 lines
34 KiB
Python
1050 lines
34 KiB
Python
import heapq
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import logging
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from typing import (
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Dict,
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Generic,
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Iterable,
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Iterator,
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List,
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Optional,
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Sequence,
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Set,
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Tuple,
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TypeVar,
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Union,
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cast,
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)
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from .pdfcolor import PDFColorSpace
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from .pdffont import PDFFont
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from .pdfinterp import Color
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from .pdfinterp import PDFGraphicState
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from .pdftypes import PDFStream
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from .utils import INF, PathSegment
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from .utils import LTComponentT
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from .utils import Matrix
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from .utils import Plane
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from .utils import Point
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from .utils import Rect
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from .utils import apply_matrix_pt
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from .utils import bbox2str
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from .utils import fsplit
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from .utils import get_bound
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from .utils import matrix2str
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from .utils import uniq
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logger = logging.getLogger(__name__)
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class IndexAssigner:
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def __init__(self, index: int = 0) -> None:
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self.index = index
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def run(self, obj: "LTItem") -> None:
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if isinstance(obj, LTTextBox):
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obj.index = self.index
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self.index += 1
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elif isinstance(obj, LTTextGroup):
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for x in obj:
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self.run(x)
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class LAParams:
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"""Parameters for layout analysis
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:param line_overlap: If two characters have more overlap than this they
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are considered to be on the same line. The overlap is specified
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relative to the minimum height of both characters.
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:param char_margin: If two characters are closer together than this
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margin they are considered part of the same line. The margin is
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specified relative to the width of the character.
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:param word_margin: If two characters on the same line are further apart
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than this margin then they are considered to be two separate words, and
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an intermediate space will be added for readability. The margin is
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specified relative to the width of the character.
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:param line_margin: If two lines are are close together they are
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considered to be part of the same paragraph. The margin is
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specified relative to the height of a line.
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:param boxes_flow: Specifies how much a horizontal and vertical position
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of a text matters when determining the order of text boxes. The value
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should be within the range of -1.0 (only horizontal position
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matters) to +1.0 (only vertical position matters). You can also pass
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`None` to disable advanced layout analysis, and instead return text
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based on the position of the bottom left corner of the text box.
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:param detect_vertical: If vertical text should be considered during
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layout analysis
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:param all_texts: If layout analysis should be performed on text in
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figures.
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"""
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def __init__(
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self,
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line_overlap: float = 0.5,
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char_margin: float = 2.0,
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line_margin: float = 0.5,
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word_margin: float = 0.1,
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boxes_flow: Optional[float] = 0.5,
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detect_vertical: bool = False,
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all_texts: bool = False,
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) -> None:
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self.line_overlap = line_overlap
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self.char_margin = char_margin
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self.line_margin = line_margin
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self.word_margin = word_margin
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self.boxes_flow = boxes_flow
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self.detect_vertical = detect_vertical
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self.all_texts = all_texts
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self._validate()
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def _validate(self) -> None:
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if self.boxes_flow is not None:
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boxes_flow_err_msg = (
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"LAParam boxes_flow should be None, or a " "number between -1 and +1"
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)
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if not (
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isinstance(self.boxes_flow, int) or isinstance(self.boxes_flow, float)
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):
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raise TypeError(boxes_flow_err_msg)
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if not -1 <= self.boxes_flow <= 1:
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raise ValueError(boxes_flow_err_msg)
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def __repr__(self) -> str:
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return (
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"<LAParams: char_margin=%.1f, line_margin=%.1f, "
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"word_margin=%.1f all_texts=%r>"
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% (self.char_margin, self.line_margin, self.word_margin, self.all_texts)
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)
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class LTItem:
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"""Interface for things that can be analyzed"""
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def analyze(self, laparams: LAParams) -> None:
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"""Perform the layout analysis."""
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pass
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class LTText:
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"""Interface for things that have text"""
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def __repr__(self) -> str:
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return "<%s %r>" % (self.__class__.__name__, self.get_text())
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def get_text(self) -> str:
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"""Text contained in this object"""
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raise NotImplementedError
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class LTComponent(LTItem):
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"""Object with a bounding box"""
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def __init__(self, bbox: Rect) -> None:
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LTItem.__init__(self)
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self.set_bbox(bbox)
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def __repr__(self) -> str:
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return "<%s %s>" % (self.__class__.__name__, bbox2str(self.bbox))
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# Disable comparison.
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def __lt__(self, _: object) -> bool:
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raise ValueError
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def __le__(self, _: object) -> bool:
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raise ValueError
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def __gt__(self, _: object) -> bool:
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raise ValueError
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def __ge__(self, _: object) -> bool:
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raise ValueError
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def set_bbox(self, bbox: Rect) -> None:
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(x0, y0, x1, y1) = bbox
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self.x0 = x0
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self.y0 = y0
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self.x1 = x1
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self.y1 = y1
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self.width = x1 - x0
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self.height = y1 - y0
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self.bbox = bbox
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def is_empty(self) -> bool:
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return self.width <= 0 or self.height <= 0
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def is_hoverlap(self, obj: "LTComponent") -> bool:
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assert isinstance(obj, LTComponent), str(type(obj))
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return obj.x0 <= self.x1 and self.x0 <= obj.x1
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def hdistance(self, obj: "LTComponent") -> float:
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assert isinstance(obj, LTComponent), str(type(obj))
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if self.is_hoverlap(obj):
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return 0
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else:
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return min(abs(self.x0 - obj.x1), abs(self.x1 - obj.x0))
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def hoverlap(self, obj: "LTComponent") -> float:
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assert isinstance(obj, LTComponent), str(type(obj))
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if self.is_hoverlap(obj):
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return min(abs(self.x0 - obj.x1), abs(self.x1 - obj.x0))
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else:
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return 0
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def is_voverlap(self, obj: "LTComponent") -> bool:
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assert isinstance(obj, LTComponent), str(type(obj))
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return obj.y0 <= self.y1 and self.y0 <= obj.y1
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def vdistance(self, obj: "LTComponent") -> float:
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assert isinstance(obj, LTComponent), str(type(obj))
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if self.is_voverlap(obj):
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return 0
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else:
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return min(abs(self.y0 - obj.y1), abs(self.y1 - obj.y0))
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def voverlap(self, obj: "LTComponent") -> float:
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assert isinstance(obj, LTComponent), str(type(obj))
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if self.is_voverlap(obj):
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return min(abs(self.y0 - obj.y1), abs(self.y1 - obj.y0))
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else:
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return 0
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class LTCurve(LTComponent):
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"""
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A generic Bezier curve
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The parameter `original_path` contains the original
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pathing information from the pdf (e.g. for reconstructing Bezier Curves).
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`dashing_style` contains the Dashing information if any.
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"""
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def __init__(
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self,
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linewidth: float,
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pts: List[Point],
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stroke: bool = False,
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fill: bool = False,
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evenodd: bool = False,
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stroking_color: Optional[Color] = None,
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non_stroking_color: Optional[Color] = None,
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original_path: Optional[List[PathSegment]] = None,
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dashing_style: Optional[Tuple[object, object]] = None,
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) -> None:
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LTComponent.__init__(self, get_bound(pts))
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self.pts = pts
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self.linewidth = linewidth
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self.stroke = stroke
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self.fill = fill
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self.evenodd = evenodd
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self.stroking_color = stroking_color
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self.non_stroking_color = non_stroking_color
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self.original_path = original_path
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self.dashing_style = dashing_style
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def get_pts(self) -> str:
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return ",".join("%.3f,%.3f" % p for p in self.pts)
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class LTLine(LTCurve):
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"""A single straight line.
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Could be used for separating text or figures.
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"""
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def __init__(
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self,
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linewidth: float,
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p0: Point,
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p1: Point,
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stroke: bool = False,
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fill: bool = False,
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evenodd: bool = False,
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stroking_color: Optional[Color] = None,
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non_stroking_color: Optional[Color] = None,
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original_path: Optional[List[PathSegment]] = None,
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dashing_style: Optional[Tuple[object, object]] = None,
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) -> None:
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LTCurve.__init__(
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self,
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linewidth,
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[p0, p1],
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stroke,
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fill,
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evenodd,
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stroking_color,
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non_stroking_color,
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original_path,
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dashing_style,
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)
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class LTRect(LTCurve):
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"""A rectangle.
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Could be used for framing another pictures or figures.
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"""
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def __init__(
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self,
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linewidth: float,
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bbox: Rect,
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stroke: bool = False,
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fill: bool = False,
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evenodd: bool = False,
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stroking_color: Optional[Color] = None,
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non_stroking_color: Optional[Color] = None,
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original_path: Optional[List[PathSegment]] = None,
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dashing_style: Optional[Tuple[object, object]] = None,
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) -> None:
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(x0, y0, x1, y1) = bbox
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LTCurve.__init__(
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self,
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linewidth,
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[(x0, y0), (x1, y0), (x1, y1), (x0, y1)],
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stroke,
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fill,
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evenodd,
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stroking_color,
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non_stroking_color,
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original_path,
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dashing_style,
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)
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class LTImage(LTComponent):
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"""An image object.
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Embedded images can be in JPEG, Bitmap or JBIG2.
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"""
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def __init__(self, name: str, stream: PDFStream, bbox: Rect) -> None:
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LTComponent.__init__(self, bbox)
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self.name = name
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self.stream = stream
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self.srcsize = (stream.get_any(("W", "Width")), stream.get_any(("H", "Height")))
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self.imagemask = stream.get_any(("IM", "ImageMask"))
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self.bits = stream.get_any(("BPC", "BitsPerComponent"), 1)
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self.colorspace = stream.get_any(("CS", "ColorSpace"))
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if not isinstance(self.colorspace, list):
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self.colorspace = [self.colorspace]
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def __repr__(self) -> str:
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return "<%s(%s) %s %r>" % (
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self.__class__.__name__,
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self.name,
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bbox2str(self.bbox),
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self.srcsize,
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)
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class LTAnno(LTItem, LTText):
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"""Actual letter in the text as a Unicode string.
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Note that, while a LTChar object has actual boundaries, LTAnno objects does
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not, as these are "virtual" characters, inserted by a layout analyzer
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according to the relationship between two characters (e.g. a space).
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"""
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def __init__(self, text: str) -> None:
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self._text = text
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return
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def get_text(self) -> str:
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return self._text
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class LTChar(LTComponent, LTText):
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"""Actual letter in the text as a Unicode string."""
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def __init__(
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self,
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matrix: Matrix,
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font: PDFFont,
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fontsize: float,
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scaling: float,
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rise: float,
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text: str,
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textwidth: float,
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textdisp: Union[float, Tuple[Optional[float], float]],
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ncs: PDFColorSpace,
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graphicstate: PDFGraphicState,
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) -> None:
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LTText.__init__(self)
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self._text = text
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self.matrix = matrix
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self.fontname = font.fontname
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self.ncs = ncs
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self.graphicstate = graphicstate
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self.adv = textwidth * fontsize * scaling
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# compute the boundary rectangle.
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if font.is_vertical():
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# vertical
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assert isinstance(textdisp, tuple)
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(vx, vy) = textdisp
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if vx is None:
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vx = fontsize * 0.5
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else:
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vx = vx * fontsize * 0.001
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vy = (1000 - vy) * fontsize * 0.001
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bbox_lower_left = (-vx, vy + rise + self.adv)
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bbox_upper_right = (-vx + fontsize, vy + rise)
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else:
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# horizontal
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descent = font.get_descent() * fontsize
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bbox_lower_left = (0, descent + rise)
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bbox_upper_right = (self.adv, descent + rise + fontsize)
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(a, b, c, d, e, f) = self.matrix
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self.upright = 0 < a * d * scaling and b * c <= 0
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(x0, y0) = apply_matrix_pt(self.matrix, bbox_lower_left)
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(x1, y1) = apply_matrix_pt(self.matrix, bbox_upper_right)
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if x1 < x0:
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(x0, x1) = (x1, x0)
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if y1 < y0:
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(y0, y1) = (y1, y0)
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LTComponent.__init__(self, (x0, y0, x1, y1))
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if font.is_vertical():
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self.size = self.width
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else:
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self.size = self.height
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return
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def __repr__(self) -> str:
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return "<%s %s matrix=%s font=%r adv=%s text=%r>" % (
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self.__class__.__name__,
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bbox2str(self.bbox),
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matrix2str(self.matrix),
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self.fontname,
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self.adv,
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self.get_text(),
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)
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def get_text(self) -> str:
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return self._text
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def is_compatible(self, obj: object) -> bool:
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"""Returns True if two characters can coexist in the same line."""
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return True
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|
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LTItemT = TypeVar("LTItemT", bound=LTItem)
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|
|
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class LTContainer(LTComponent, Generic[LTItemT]):
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"""Object that can be extended and analyzed"""
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def __init__(self, bbox: Rect) -> None:
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LTComponent.__init__(self, bbox)
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self._objs: List[LTItemT] = []
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return
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def __iter__(self) -> Iterator[LTItemT]:
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return iter(self._objs)
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|
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def __len__(self) -> int:
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return len(self._objs)
|
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|
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def add(self, obj: LTItemT) -> None:
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self._objs.append(obj)
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return
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|
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def extend(self, objs: Iterable[LTItemT]) -> None:
|
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for obj in objs:
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self.add(obj)
|
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return
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|
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def analyze(self, laparams: LAParams) -> None:
|
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for obj in self._objs:
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obj.analyze(laparams)
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return
|
|
|
|
|
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class LTExpandableContainer(LTContainer[LTItemT]):
|
|
def __init__(self) -> None:
|
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LTContainer.__init__(self, (+INF, +INF, -INF, -INF))
|
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return
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|
|
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# Incompatible override: we take an LTComponent (with bounding box), but
|
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# super() LTContainer only considers LTItem (no bounding box).
|
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def add(self, obj: LTComponent) -> None: # type: ignore[override]
|
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LTContainer.add(self, cast(LTItemT, obj))
|
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self.set_bbox(
|
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(
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min(self.x0, obj.x0),
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min(self.y0, obj.y0),
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max(self.x1, obj.x1),
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max(self.y1, obj.y1),
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)
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)
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return
|
|
|
|
|
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class LTTextContainer(LTExpandableContainer[LTItemT], LTText):
|
|
def __init__(self) -> None:
|
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LTText.__init__(self)
|
|
LTExpandableContainer.__init__(self)
|
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return
|
|
|
|
def get_text(self) -> str:
|
|
return "".join(
|
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cast(LTText, obj).get_text() for obj in self if isinstance(obj, LTText)
|
|
)
|
|
|
|
|
|
TextLineElement = Union[LTChar, LTAnno]
|
|
|
|
|
|
class LTTextLine(LTTextContainer[TextLineElement]):
|
|
"""Contains a list of LTChar objects that represent a single text line.
|
|
|
|
The characters are aligned either horizontally or vertically, depending on
|
|
the text's writing mode.
|
|
"""
|
|
|
|
def __init__(self, word_margin: float) -> None:
|
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super().__init__()
|
|
self.word_margin = word_margin
|
|
return
|
|
|
|
def __repr__(self) -> str:
|
|
return "<%s %s %r>" % (
|
|
self.__class__.__name__,
|
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bbox2str(self.bbox),
|
|
self.get_text(),
|
|
)
|
|
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
for obj in self._objs:
|
|
obj.analyze(laparams)
|
|
LTContainer.add(self, LTAnno("\n"))
|
|
return
|
|
|
|
def find_neighbors(
|
|
self, plane: Plane[LTComponentT], ratio: float
|
|
) -> List["LTTextLine"]:
|
|
raise NotImplementedError
|
|
|
|
def is_empty(self) -> bool:
|
|
return super().is_empty() or self.get_text().isspace()
|
|
|
|
|
|
class LTTextLineHorizontal(LTTextLine):
|
|
def __init__(self, word_margin: float) -> None:
|
|
LTTextLine.__init__(self, word_margin)
|
|
self._x1: float = +INF
|
|
return
|
|
|
|
# Incompatible override: we take an LTComponent (with bounding box), but
|
|
# LTContainer only considers LTItem (no bounding box).
|
|
def add(self, obj: LTComponent) -> None: # type: ignore[override]
|
|
if isinstance(obj, LTChar) and self.word_margin:
|
|
margin = self.word_margin * max(obj.width, obj.height)
|
|
if self._x1 < obj.x0 - margin:
|
|
LTContainer.add(self, LTAnno(" "))
|
|
self._x1 = obj.x1
|
|
super().add(obj)
|
|
return
|
|
|
|
def find_neighbors(
|
|
self, plane: Plane[LTComponentT], ratio: float
|
|
) -> List[LTTextLine]:
|
|
"""
|
|
Finds neighboring LTTextLineHorizontals in the plane.
|
|
|
|
Returns a list of other LTTestLineHorizontals in the plane which are
|
|
close to self. "Close" can be controlled by ratio. The returned objects
|
|
will be the same height as self, and also either left-, right-, or
|
|
centrally-aligned.
|
|
"""
|
|
d = ratio * self.height
|
|
objs = plane.find((self.x0, self.y0 - d, self.x1, self.y1 + d))
|
|
return [
|
|
obj
|
|
for obj in objs
|
|
if (
|
|
isinstance(obj, LTTextLineHorizontal)
|
|
and self._is_same_height_as(obj, tolerance=d)
|
|
and (
|
|
self._is_left_aligned_with(obj, tolerance=d)
|
|
or self._is_right_aligned_with(obj, tolerance=d)
|
|
or self._is_centrally_aligned_with(obj, tolerance=d)
|
|
)
|
|
)
|
|
]
|
|
|
|
def _is_left_aligned_with(self, other: LTComponent, tolerance: float = 0) -> bool:
|
|
"""
|
|
Whether the left-hand edge of `other` is within `tolerance`.
|
|
"""
|
|
return abs(other.x0 - self.x0) <= tolerance
|
|
|
|
def _is_right_aligned_with(self, other: LTComponent, tolerance: float = 0) -> bool:
|
|
"""
|
|
Whether the right-hand edge of `other` is within `tolerance`.
|
|
"""
|
|
return abs(other.x1 - self.x1) <= tolerance
|
|
|
|
def _is_centrally_aligned_with(
|
|
self, other: LTComponent, tolerance: float = 0
|
|
) -> bool:
|
|
"""
|
|
Whether the horizontal center of `other` is within `tolerance`.
|
|
"""
|
|
return abs((other.x0 + other.x1) / 2 - (self.x0 + self.x1) / 2) <= tolerance
|
|
|
|
def _is_same_height_as(self, other: LTComponent, tolerance: float = 0) -> bool:
|
|
return abs(other.height - self.height) <= tolerance
|
|
|
|
|
|
class LTTextLineVertical(LTTextLine):
|
|
def __init__(self, word_margin: float) -> None:
|
|
LTTextLine.__init__(self, word_margin)
|
|
self._y0: float = -INF
|
|
return
|
|
|
|
# Incompatible override: we take an LTComponent (with bounding box), but
|
|
# LTContainer only considers LTItem (no bounding box).
|
|
def add(self, obj: LTComponent) -> None: # type: ignore[override]
|
|
if isinstance(obj, LTChar) and self.word_margin:
|
|
margin = self.word_margin * max(obj.width, obj.height)
|
|
if obj.y1 + margin < self._y0:
|
|
LTContainer.add(self, LTAnno(" "))
|
|
self._y0 = obj.y0
|
|
super().add(obj)
|
|
return
|
|
|
|
def find_neighbors(
|
|
self, plane: Plane[LTComponentT], ratio: float
|
|
) -> List[LTTextLine]:
|
|
"""
|
|
Finds neighboring LTTextLineVerticals in the plane.
|
|
|
|
Returns a list of other LTTextLineVerticals in the plane which are
|
|
close to self. "Close" can be controlled by ratio. The returned objects
|
|
will be the same width as self, and also either upper-, lower-, or
|
|
centrally-aligned.
|
|
"""
|
|
d = ratio * self.width
|
|
objs = plane.find((self.x0 - d, self.y0, self.x1 + d, self.y1))
|
|
return [
|
|
obj
|
|
for obj in objs
|
|
if (
|
|
isinstance(obj, LTTextLineVertical)
|
|
and self._is_same_width_as(obj, tolerance=d)
|
|
and (
|
|
self._is_lower_aligned_with(obj, tolerance=d)
|
|
or self._is_upper_aligned_with(obj, tolerance=d)
|
|
or self._is_centrally_aligned_with(obj, tolerance=d)
|
|
)
|
|
)
|
|
]
|
|
|
|
def _is_lower_aligned_with(self, other: LTComponent, tolerance: float = 0) -> bool:
|
|
"""
|
|
Whether the lower edge of `other` is within `tolerance`.
|
|
"""
|
|
return abs(other.y0 - self.y0) <= tolerance
|
|
|
|
def _is_upper_aligned_with(self, other: LTComponent, tolerance: float = 0) -> bool:
|
|
"""
|
|
Whether the upper edge of `other` is within `tolerance`.
|
|
"""
|
|
return abs(other.y1 - self.y1) <= tolerance
|
|
|
|
def _is_centrally_aligned_with(
|
|
self, other: LTComponent, tolerance: float = 0
|
|
) -> bool:
|
|
"""
|
|
Whether the vertical center of `other` is within `tolerance`.
|
|
"""
|
|
return abs((other.y0 + other.y1) / 2 - (self.y0 + self.y1) / 2) <= tolerance
|
|
|
|
def _is_same_width_as(self, other: LTComponent, tolerance: float) -> bool:
|
|
return abs(other.width - self.width) <= tolerance
|
|
|
|
|
|
class LTTextBox(LTTextContainer[LTTextLine]):
|
|
"""Represents a group of text chunks in a rectangular area.
|
|
|
|
Note that this box is created by geometric analysis and does not
|
|
necessarily represents a logical boundary of the text. It contains a list
|
|
of LTTextLine objects.
|
|
"""
|
|
|
|
def __init__(self) -> None:
|
|
LTTextContainer.__init__(self)
|
|
self.index: int = -1
|
|
return
|
|
|
|
def __repr__(self) -> str:
|
|
return "<%s(%s) %s %r>" % (
|
|
self.__class__.__name__,
|
|
self.index,
|
|
bbox2str(self.bbox),
|
|
self.get_text(),
|
|
)
|
|
|
|
def get_writing_mode(self) -> str:
|
|
raise NotImplementedError
|
|
|
|
|
|
class LTTextBoxHorizontal(LTTextBox):
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
super().analyze(laparams)
|
|
self._objs.sort(key=lambda obj: -obj.y1)
|
|
return
|
|
|
|
def get_writing_mode(self) -> str:
|
|
return "lr-tb"
|
|
|
|
|
|
class LTTextBoxVertical(LTTextBox):
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
super().analyze(laparams)
|
|
self._objs.sort(key=lambda obj: -obj.x1)
|
|
return
|
|
|
|
def get_writing_mode(self) -> str:
|
|
return "tb-rl"
|
|
|
|
|
|
TextGroupElement = Union[LTTextBox, "LTTextGroup"]
|
|
|
|
|
|
class LTTextGroup(LTTextContainer[TextGroupElement]):
|
|
def __init__(self, objs: Iterable[TextGroupElement]) -> None:
|
|
super().__init__()
|
|
self.extend(objs)
|
|
return
|
|
|
|
|
|
class LTTextGroupLRTB(LTTextGroup):
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
super().analyze(laparams)
|
|
assert laparams.boxes_flow is not None
|
|
boxes_flow = laparams.boxes_flow
|
|
# reorder the objects from top-left to bottom-right.
|
|
self._objs.sort(
|
|
key=lambda obj: (1 - boxes_flow) * obj.x0
|
|
- (1 + boxes_flow) * (obj.y0 + obj.y1)
|
|
)
|
|
return
|
|
|
|
|
|
class LTTextGroupTBRL(LTTextGroup):
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
super().analyze(laparams)
|
|
assert laparams.boxes_flow is not None
|
|
boxes_flow = laparams.boxes_flow
|
|
# reorder the objects from top-right to bottom-left.
|
|
self._objs.sort(
|
|
key=lambda obj: -(1 + boxes_flow) * (obj.x0 + obj.x1)
|
|
- (1 - boxes_flow) * obj.y1
|
|
)
|
|
return
|
|
|
|
|
|
class LTLayoutContainer(LTContainer[LTComponent]):
|
|
def __init__(self, bbox: Rect) -> None:
|
|
LTContainer.__init__(self, bbox)
|
|
self.groups: Optional[List[LTTextGroup]] = None
|
|
return
|
|
|
|
# group_objects: group text object to textlines.
|
|
def group_objects(
|
|
self, laparams: LAParams, objs: Iterable[LTComponent]
|
|
) -> Iterator[LTTextLine]:
|
|
obj0 = None
|
|
line = None
|
|
for obj1 in objs:
|
|
if obj0 is not None:
|
|
# halign: obj0 and obj1 is horizontally aligned.
|
|
#
|
|
# +------+ - - -
|
|
# | obj0 | - - +------+ -
|
|
# | | | obj1 | | (line_overlap)
|
|
# +------+ - - | | -
|
|
# - - - +------+
|
|
#
|
|
# |<--->|
|
|
# (char_margin)
|
|
halign = (
|
|
obj0.is_compatible(obj1)
|
|
and obj0.is_voverlap(obj1)
|
|
and min(obj0.height, obj1.height) * laparams.line_overlap
|
|
< obj0.voverlap(obj1)
|
|
and obj0.hdistance(obj1)
|
|
< max(obj0.width, obj1.width) * laparams.char_margin
|
|
)
|
|
|
|
# valign: obj0 and obj1 is vertically aligned.
|
|
#
|
|
# +------+
|
|
# | obj0 |
|
|
# | |
|
|
# +------+ - - -
|
|
# | | | (char_margin)
|
|
# +------+ - -
|
|
# | obj1 |
|
|
# | |
|
|
# +------+
|
|
#
|
|
# |<-->|
|
|
# (line_overlap)
|
|
valign = (
|
|
laparams.detect_vertical
|
|
and obj0.is_compatible(obj1)
|
|
and obj0.is_hoverlap(obj1)
|
|
and min(obj0.width, obj1.width) * laparams.line_overlap
|
|
< obj0.hoverlap(obj1)
|
|
and obj0.vdistance(obj1)
|
|
< max(obj0.height, obj1.height) * laparams.char_margin
|
|
)
|
|
|
|
if (halign and isinstance(line, LTTextLineHorizontal)) or (
|
|
valign and isinstance(line, LTTextLineVertical)
|
|
):
|
|
|
|
line.add(obj1)
|
|
elif line is not None:
|
|
yield line
|
|
line = None
|
|
else:
|
|
if valign and not halign:
|
|
line = LTTextLineVertical(laparams.word_margin)
|
|
line.add(obj0)
|
|
line.add(obj1)
|
|
elif halign and not valign:
|
|
line = LTTextLineHorizontal(laparams.word_margin)
|
|
line.add(obj0)
|
|
line.add(obj1)
|
|
else:
|
|
line = LTTextLineHorizontal(laparams.word_margin)
|
|
line.add(obj0)
|
|
yield line
|
|
line = None
|
|
obj0 = obj1
|
|
if line is None:
|
|
line = LTTextLineHorizontal(laparams.word_margin)
|
|
assert obj0 is not None
|
|
line.add(obj0)
|
|
yield line
|
|
return
|
|
|
|
def group_textlines(
|
|
self, laparams: LAParams, lines: Iterable[LTTextLine]
|
|
) -> Iterator[LTTextBox]:
|
|
"""Group neighboring lines to textboxes"""
|
|
plane: Plane[LTTextLine] = Plane(self.bbox)
|
|
plane.extend(lines)
|
|
boxes: Dict[LTTextLine, LTTextBox] = {}
|
|
for line in lines:
|
|
neighbors = line.find_neighbors(plane, laparams.line_margin)
|
|
members = [line]
|
|
for obj1 in neighbors:
|
|
members.append(obj1)
|
|
if obj1 in boxes:
|
|
members.extend(boxes.pop(obj1))
|
|
if isinstance(line, LTTextLineHorizontal):
|
|
box: LTTextBox = LTTextBoxHorizontal()
|
|
else:
|
|
box = LTTextBoxVertical()
|
|
for obj in uniq(members):
|
|
box.add(obj)
|
|
boxes[obj] = box
|
|
done = set()
|
|
for line in lines:
|
|
if line not in boxes:
|
|
continue
|
|
box = boxes[line]
|
|
if box in done:
|
|
continue
|
|
done.add(box)
|
|
if not box.is_empty():
|
|
yield box
|
|
return
|
|
|
|
def group_textboxes(
|
|
self, laparams: LAParams, boxes: Sequence[LTTextBox]
|
|
) -> List[LTTextGroup]:
|
|
"""Group textboxes hierarchically.
|
|
|
|
Get pair-wise distances, via dist func defined below, and then merge
|
|
from the closest textbox pair. Once obj1 and obj2 are merged /
|
|
grouped, the resulting group is considered as a new object, and its
|
|
distances to other objects & groups are added to the process queue.
|
|
|
|
For performance reason, pair-wise distances and object pair info are
|
|
maintained in a heap of (idx, dist, id(obj1), id(obj2), obj1, obj2)
|
|
tuples. It ensures quick access to the smallest element. Note that
|
|
since comparison operators, e.g., __lt__, are disabled for
|
|
LTComponent, id(obj) has to appear before obj in element tuples.
|
|
|
|
:param laparams: LAParams object.
|
|
:param boxes: All textbox objects to be grouped.
|
|
:return: a list that has only one element, the final top level group.
|
|
"""
|
|
|
|
ElementT = Union[LTTextBox, LTTextGroup]
|
|
plane: Plane[ElementT] = Plane(self.bbox)
|
|
|
|
def dist(obj1: LTComponent, obj2: LTComponent) -> float:
|
|
"""A distance function between two TextBoxes.
|
|
|
|
Consider the bounding rectangle for obj1 and obj2.
|
|
Return its area less the areas of obj1 and obj2,
|
|
shown as 'www' below. This value may be negative.
|
|
+------+..........+ (x1, y1)
|
|
| obj1 |wwwwwwwwww:
|
|
+------+www+------+
|
|
:wwwwwwwwww| obj2 |
|
|
(x0, y0) +..........+------+
|
|
"""
|
|
x0 = min(obj1.x0, obj2.x0)
|
|
y0 = min(obj1.y0, obj2.y0)
|
|
x1 = max(obj1.x1, obj2.x1)
|
|
y1 = max(obj1.y1, obj2.y1)
|
|
return (
|
|
(x1 - x0) * (y1 - y0)
|
|
- obj1.width * obj1.height
|
|
- obj2.width * obj2.height
|
|
)
|
|
|
|
def isany(obj1: ElementT, obj2: ElementT) -> Set[ElementT]:
|
|
"""Check if there's any other object between obj1 and obj2."""
|
|
x0 = min(obj1.x0, obj2.x0)
|
|
y0 = min(obj1.y0, obj2.y0)
|
|
x1 = max(obj1.x1, obj2.x1)
|
|
y1 = max(obj1.y1, obj2.y1)
|
|
objs = set(plane.find((x0, y0, x1, y1)))
|
|
return objs.difference((obj1, obj2))
|
|
|
|
dists: List[Tuple[bool, float, int, int, ElementT, ElementT]] = []
|
|
for i in range(len(boxes)):
|
|
box1 = boxes[i]
|
|
for j in range(i + 1, len(boxes)):
|
|
box2 = boxes[j]
|
|
dists.append((False, dist(box1, box2), id(box1), id(box2), box1, box2))
|
|
heapq.heapify(dists)
|
|
|
|
plane.extend(boxes)
|
|
done = set()
|
|
while len(dists) > 0:
|
|
(skip_isany, d, id1, id2, obj1, obj2) = heapq.heappop(dists)
|
|
# Skip objects that are already merged
|
|
if (id1 not in done) and (id2 not in done):
|
|
if not skip_isany and isany(obj1, obj2):
|
|
heapq.heappush(dists, (True, d, id1, id2, obj1, obj2))
|
|
continue
|
|
if isinstance(obj1, (LTTextBoxVertical, LTTextGroupTBRL)) or isinstance(
|
|
obj2, (LTTextBoxVertical, LTTextGroupTBRL)
|
|
):
|
|
group: LTTextGroup = LTTextGroupTBRL([obj1, obj2])
|
|
else:
|
|
group = LTTextGroupLRTB([obj1, obj2])
|
|
plane.remove(obj1)
|
|
plane.remove(obj2)
|
|
done.update([id1, id2])
|
|
|
|
for other in plane:
|
|
heapq.heappush(
|
|
dists,
|
|
(False, dist(group, other), id(group), id(other), group, other),
|
|
)
|
|
plane.add(group)
|
|
# By now only groups are in the plane
|
|
return list(cast(LTTextGroup, g) for g in plane)
|
|
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
# textobjs is a list of LTChar objects, i.e.
|
|
# it has all the individual characters in the page.
|
|
(textobjs, otherobjs) = fsplit(lambda obj: isinstance(obj, LTChar), self)
|
|
for obj in otherobjs:
|
|
obj.analyze(laparams)
|
|
if not textobjs:
|
|
return
|
|
textlines = list(self.group_objects(laparams, textobjs))
|
|
(empties, textlines) = fsplit(lambda obj: obj.is_empty(), textlines)
|
|
for obj in empties:
|
|
obj.analyze(laparams)
|
|
textboxes = list(self.group_textlines(laparams, textlines))
|
|
if laparams.boxes_flow is None:
|
|
for textbox in textboxes:
|
|
textbox.analyze(laparams)
|
|
|
|
def getkey(box: LTTextBox) -> Tuple[int, float, float]:
|
|
if isinstance(box, LTTextBoxVertical):
|
|
return (0, -box.x1, -box.y0)
|
|
else:
|
|
return (1, -box.y0, box.x0)
|
|
|
|
textboxes.sort(key=getkey)
|
|
else:
|
|
self.groups = self.group_textboxes(laparams, textboxes)
|
|
assigner = IndexAssigner()
|
|
for group in self.groups:
|
|
group.analyze(laparams)
|
|
assigner.run(group)
|
|
textboxes.sort(key=lambda box: box.index)
|
|
self._objs = (
|
|
cast(List[LTComponent], textboxes)
|
|
+ otherobjs
|
|
+ cast(List[LTComponent], empties)
|
|
)
|
|
return
|
|
|
|
|
|
class LTFigure(LTLayoutContainer):
|
|
"""Represents an area used by PDF Form objects.
|
|
|
|
PDF Forms can be used to present figures or pictures by embedding yet
|
|
another PDF document within a page. Note that LTFigure objects can appear
|
|
recursively.
|
|
"""
|
|
|
|
def __init__(self, name: str, bbox: Rect, matrix: Matrix) -> None:
|
|
self.name = name
|
|
self.matrix = matrix
|
|
(x, y, w, h) = bbox
|
|
bounds = ((x, y), (x + w, y), (x, y + h), (x + w, y + h))
|
|
bbox = get_bound(apply_matrix_pt(matrix, (p, q)) for (p, q) in bounds)
|
|
LTLayoutContainer.__init__(self, bbox)
|
|
return
|
|
|
|
def __repr__(self) -> str:
|
|
return "<%s(%s) %s matrix=%s>" % (
|
|
self.__class__.__name__,
|
|
self.name,
|
|
bbox2str(self.bbox),
|
|
matrix2str(self.matrix),
|
|
)
|
|
|
|
def analyze(self, laparams: LAParams) -> None:
|
|
if not laparams.all_texts:
|
|
return
|
|
LTLayoutContainer.analyze(self, laparams)
|
|
return
|
|
|
|
|
|
class LTPage(LTLayoutContainer):
|
|
"""Represents an entire page.
|
|
|
|
Like any other LTLayoutContainer, an LTPage can be iterated to obtain child
|
|
objects like LTTextBox, LTFigure, LTImage, LTRect, LTCurve and LTLine.
|
|
"""
|
|
|
|
def __init__(self, pageid: int, bbox: Rect, rotate: float = 0) -> None:
|
|
LTLayoutContainer.__init__(self, bbox)
|
|
self.pageid = pageid
|
|
self.rotate = rotate
|
|
return
|
|
|
|
def __repr__(self) -> str:
|
|
return "<%s(%r) %s rotate=%r>" % (
|
|
self.__class__.__name__,
|
|
self.pageid,
|
|
bbox2str(self.bbox),
|
|
self.rotate,
|
|
)
|