# Copyright (c) 2006, Mathieu Fenniak # Copyright (c) 2007, Ashish Kulkarni # # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright notice, # this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above copyright notice, # this list of conditions and the following disclaimer in the documentation # and/or other materials provided with the distribution. # * The name of the author may not be used to endorse or promote products # derived from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE # LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR # CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF # SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS # INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN # CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE # POSSIBILITY OF SUCH DAMAGE. import math from typing import Any, Callable, Optional, Union from .._cmap import build_font_width_map, compute_font_width, get_actual_str_key from ..generic import DictionaryObject, TextStringObject from . import OrientationNotFoundError, crlf_space_check, get_display_str, get_text_operands, mult class TextExtraction: """ A class to handle PDF text extraction operations. This class encapsulates all the state and operations needed for extracting text from PDF content streams, replacing the nested functions and nonlocal variables in the original implementation. """ def __init__(self) -> None: self._font_width_maps: dict[str, tuple[dict[Any, float], str, float]] = {} # Text extraction state variables self.cm_matrix: list[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self.tm_matrix: list[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self.cm_stack: list[ tuple[ list[float], tuple[Union[str, dict[int, str]], dict[str, str], str, Optional[DictionaryObject]], float, float, float, float, float, ] ] = [] # Store the last modified matrices; can be an intermediate position self.cm_prev: list[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self.tm_prev: list[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] # Store the position at the beginning of building the text self.memo_cm: list[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self.memo_tm: list[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self.char_scale = 1.0 self.space_scale = 1.0 self._space_width: float = 500.0 # will be set correctly at first Tf self._actual_str_size: dict[str, float] = { "str_widths": 0.0, "space_width": 0.0, "str_height": 0.0, } # will be set to string length calculation result self.TL = 0.0 self.font_size = 12.0 # init just in case of # Text extraction variables self.text: str = "" self.output: str = "" self.rtl_dir: bool = False # right-to-left self.cmap: tuple[Union[str, dict[int, str]], dict[str, str], str, Optional[DictionaryObject]] = ( "charmap", {}, "NotInitialized", None, ) # (encoding, CMAP, font resource name, font) self.orientations: tuple[int, ...] = (0, 90, 180, 270) self.visitor_text: Optional[Callable[[Any, Any, Any, Any, Any], None]] = None self.cmaps: dict[str, tuple[str, float, Union[str, dict[int, str]], dict[str, str], DictionaryObject]] = {} self.operation_handlers = { b"BT": self._handle_bt, b"ET": self._handle_et, b"q": self._handle_save_graphics_state, b"Q": self._handle_restore_graphics_state, b"cm": self._handle_cm, b"Tz": self._handle_tz, b"Tw": self._handle_tw, b"TL": self._handle_tl, b"Tf": self._handle_tf, b"Td": self._handle_td, b"Tm": self._handle_tm, b"T*": self._handle_t_star, b"Tj": self._handle_tj_operation, } def initialize_extraction( self, orientations: tuple[int, ...] = (0, 90, 180, 270), visitor_text: Optional[Callable[[Any, Any, Any, Any, Any], None]] = None, cmaps: Optional[ dict[str, tuple[str, float, Union[str, dict[int, str]], dict[str, str], DictionaryObject]] ] = None, ) -> None: """Initialize the extractor with extraction parameters.""" self.orientations = orientations self.visitor_text = visitor_text self.cmaps = cmaps or {} # Reset state self.text = "" self.output = "" self.rtl_dir = False def compute_str_widths(self, str_widths: float) -> float: return str_widths / 1000 def process_operation(self, operator: bytes, operands: list[Any]) -> None: if operator in self.operation_handlers: handler = self.operation_handlers[operator] str_widths = handler(operands) # Post-process operations that affect text positioning if operator in {b"Td", b"Tm", b"T*", b"Tj"}: self._post_process_text_operation(str_widths or 0.0) def _post_process_text_operation(self, str_widths: float) -> None: """Handle common post-processing for text positioning operations.""" try: self.text, self.output, self.cm_prev, self.tm_prev = crlf_space_check( self.text, (self.cm_prev, self.tm_prev), (self.cm_matrix, self.tm_matrix), (self.memo_cm, self.memo_tm), self.cmap, self.orientations, self.output, self.font_size, self.visitor_text, str_widths, self.compute_str_widths(self._actual_str_size["space_width"]), self._actual_str_size["str_height"], ) if self.text == "": self.memo_cm = self.cm_matrix.copy() self.memo_tm = self.tm_matrix.copy() except OrientationNotFoundError: pass def _get_actual_font_widths( self, cmap: tuple[ Union[str, dict[int, str]], dict[str, str], str, Optional[DictionaryObject] ], text_operands: str, font_size: float, space_width: float, ) -> tuple[float, float, float]: font_widths: float = 0 font_name: str = cmap[2] if font_name not in self._font_width_maps: if cmap[3] is None: font_width_map: dict[Any, float] = {} space_char = " " actual_space_width: float = space_width font_width_map["default"] = actual_space_width * 2 else: space_char = get_actual_str_key(" ", cmap[0], cmap[1]) font_width_map = build_font_width_map(cmap[3], space_width * 2) actual_space_width = compute_font_width(font_width_map, space_char) if actual_space_width == 0: actual_space_width = space_width self._font_width_maps[font_name] = (font_width_map, space_char, actual_space_width) font_width_map = self._font_width_maps[font_name][0] space_char = self._font_width_maps[font_name][1] actual_space_width = self._font_width_maps[font_name][2] if text_operands: for char in text_operands: if char == space_char: font_widths += actual_space_width continue font_widths += compute_font_width(font_width_map, char) return (font_widths * font_size, space_width * font_size, font_size) def _handle_tj( self, text: str, operands: list[Union[str, TextStringObject]], cm_matrix: list[float], tm_matrix: list[float], cmap: tuple[ Union[str, dict[int, str]], dict[str, str], str, Optional[DictionaryObject] ], orientations: tuple[int, ...], font_size: float, rtl_dir: bool, visitor_text: Optional[Callable[[Any, Any, Any, Any, Any], None]], space_width: float, actual_str_size: dict[str, float], ) -> tuple[str, bool, dict[str, float]]: text_operands, is_str_operands = get_text_operands( operands, cm_matrix, tm_matrix, cmap, orientations) if is_str_operands: text += text_operands else: text, rtl_dir = get_display_str( text, cm_matrix, tm_matrix, # text matrix cmap, text_operands, font_size, rtl_dir, visitor_text, ) font_widths, actual_str_size["space_width"], actual_str_size["str_height"] = ( self._get_actual_font_widths(cmap, text_operands, font_size, space_width)) actual_str_size["str_widths"] += font_widths return text, rtl_dir, actual_str_size def _flush_text(self) -> None: """Flush accumulated text to output and call visitor if present.""" self.output += self.text if self.visitor_text is not None: self.visitor_text(self.text, self.memo_cm, self.memo_tm, self.cmap[3], self.font_size) self.text = "" self.memo_cm = self.cm_matrix.copy() self.memo_tm = self.tm_matrix.copy() # Operation handlers def _handle_bt(self, operands: list[Any]) -> None: """Handle BT (Begin Text) operation - Table 5.4 page 405.""" self.tm_matrix = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self._flush_text() def _handle_et(self, operands: list[Any]) -> None: """Handle ET (End Text) operation - Table 5.4 page 405.""" self._flush_text() def _handle_save_graphics_state(self, operands: list[Any]) -> None: """Handle q (Save graphics state) operation - Table 4.7 page 219.""" self.cm_stack.append( ( self.cm_matrix, self.cmap, self.font_size, self.char_scale, self.space_scale, self._space_width, self.TL, ) ) def _handle_restore_graphics_state(self, operands: list[Any]) -> None: """Handle Q (Restore graphics state) operation - Table 4.7 page 219.""" try: ( self.cm_matrix, self.cmap, self.font_size, self.char_scale, self.space_scale, self._space_width, self.TL, ) = self.cm_stack.pop() except Exception: self.cm_matrix = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] def _handle_cm(self, operands: list[Any]) -> None: """Handle cm (Modify current matrix) operation - Table 4.7 page 219.""" self.output += self.text if self.visitor_text is not None: self.visitor_text(self.text, self.memo_cm, self.memo_tm, self.cmap[3], self.font_size) self.text = "" try: self.cm_matrix = mult([float(operand) for operand in operands[:6]], self.cm_matrix) except Exception: self.cm_matrix = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0] self.memo_cm = self.cm_matrix.copy() self.memo_tm = self.tm_matrix.copy() def _handle_tz(self, operands: list[Any]) -> None: """Handle Tz (Set horizontal text scaling) operation - Table 5.2 page 398.""" self.char_scale = float(operands[0]) / 100 if operands else 1.0 def _handle_tw(self, operands: list[Any]) -> None: """Handle Tw (Set word spacing) operation - Table 5.2 page 398.""" self.space_scale = 1.0 + float(operands[0] if operands else 0.0) def _handle_tl(self, operands: list[Any]) -> None: """Handle TL (Set Text Leading) operation - Table 5.2 page 398.""" scale_x = math.sqrt(self.tm_matrix[0] ** 2 + self.tm_matrix[2] ** 2) self.TL = float(operands[0] if operands else 0.0) * self.font_size * scale_x def _handle_tf(self, operands: list[Any]) -> None: """Handle Tf (Set font size) operation - Table 5.2 page 398.""" if self.text != "": self.output += self.text # .translate(cmap) if self.visitor_text is not None: self.visitor_text(self.text, self.memo_cm, self.memo_tm, self.cmap[3], self.font_size) self.text = "" self.memo_cm = self.cm_matrix.copy() self.memo_tm = self.tm_matrix.copy() try: # Import here to avoid circular imports from .._cmap import unknown_char_map # noqa: PLC0415 # char_map_tuple: font_type, # float(sp_width / 2), # encoding, # map_dict, # font_dict (describes the font) char_map_tuple = self.cmaps[operands[0]] # current cmap: encoding, # map_dict, # font resource name (internal name, not the real font name), # font_dict self.cmap = ( char_map_tuple[2], char_map_tuple[3], operands[0], char_map_tuple[4], ) self._space_width = char_map_tuple[1] except KeyError: # font not found self.cmap = ( unknown_char_map[2], unknown_char_map[3], f"???{operands[0]}", None, ) self._space_width = unknown_char_map[1] try: self.font_size = float(operands[1]) except Exception: pass # keep previous size def _handle_td(self, operands: list[Any]) -> float: """Handle Td (Move text position) operation - Table 5.5 page 406.""" # A special case is a translating only tm: # tm = [1, 0, 0, 1, e, f] # i.e. tm[4] += tx, tm[5] += ty. tx, ty = float(operands[0]), float(operands[1]) self.tm_matrix[4] += tx * self.tm_matrix[0] + ty * self.tm_matrix[2] self.tm_matrix[5] += tx * self.tm_matrix[1] + ty * self.tm_matrix[3] str_widths = self.compute_str_widths(self._actual_str_size["str_widths"]) self._actual_str_size["str_widths"] = 0.0 return str_widths def _handle_tm(self, operands: list[Any]) -> float: """Handle Tm (Set text matrix) operation - Table 5.5 page 406.""" self.tm_matrix = [float(operand) for operand in operands[:6]] str_widths = self.compute_str_widths(self._actual_str_size["str_widths"]) self._actual_str_size["str_widths"] = 0.0 return str_widths def _handle_t_star(self, operands: list[Any]) -> float: """Handle T* (Move to next line) operation - Table 5.5 page 406.""" self.tm_matrix[4] -= self.TL * self.tm_matrix[2] self.tm_matrix[5] -= self.TL * self.tm_matrix[3] str_widths = self.compute_str_widths(self._actual_str_size["str_widths"]) self._actual_str_size["str_widths"] = 0.0 return str_widths def _handle_tj_operation(self, operands: list[Any]) -> float: """Handle Tj (Show text) operation - Table 5.5 page 406.""" self.text, self.rtl_dir, self._actual_str_size = self._handle_tj( self.text, operands, self.cm_matrix, self.tm_matrix, self.cmap, self.orientations, self.font_size, self.rtl_dir, self.visitor_text, self._space_width, self._actual_str_size, ) return 0.0 # str_widths will be handled in post-processing