BUG: invalid cm/tm in visitor functions

docs/user/extract-text.md

@@ -27,14 +27,27 @@ Refer to [extract\_text](../modules/PageObject.html#pypdf._page.PageObject.extra
 You can use visitor-functions to control which part of a page you want to process and extract. The visitor-functions you provide will get called for each operator or for each text fragment.
 
 The function provided in argument visitor_text of function extract_text has five arguments:
-text, current transformation matrix, text matrix, font-dictionary and font-size.
-In most cases the x and y coordinates of the current position
-are in index 4 and 5 of the current transformation matrix.
+* text: the current text (as long as possible, can be up to a full line)
+* user_matrix: current matrix to move from user coordinate space (also known as CTM)
+* tm_matrix: current matrix from text coordinate space
+* font-dictionary: full font dictionary
+* font-size: the size (in text coordinate space)
+
+The matrix stores 6 parameters. The first 4 provide the rotation/scaling matrix and the last two provide the translation (horizontal/vertical)
+It is recommended to use the user_matrix as it takes into all transformations.
+
+Notes :
+
+ - as indicated in the PDF 1.7 reference, page 204 the user matrix applies to text space/image space/form space/pattern space.
+ - if you want to get the full transformation from text to user space, you can use the `mult` function (availalbe in global import) as follows:
+`txt2user = mult(tm, cm))`
+The font-size is the raw text size, that is affected by the `user_matrix`
+
 
 The font-dictionary may be None in case of unknown fonts.
 If not None it may e.g. contain key "/BaseFont" with value "/Arial,Bold".
 
-**Caveat**: In complicated documents the calculated positions might be wrong.
+**Caveat**: In complicated documents the calculated positions may be difficult to (if you move from multiple forms to page user space for example).
 
 The function provided in argument visitor_operand_before has four arguments:
 operator, operand-arguments, current transformation matrix and text matrix.
@@ -53,7 +66,7 @@ parts = []
 
 
 def visitor_body(text, cm, tm, font_dict, font_size):
- y = tm[5]
+ y = cm[5]
  if y > 50 and y < 720:
  parts.append(text)
 
@@ -88,7 +101,7 @@ def visitor_svg_rect(op, args, cm, tm):
 
 
 def visitor_svg_text(text, cm, tm, fontDict, fontSize):
- (x, y) = (tm[4], tm[5])
+ (x, y) = (cm[4], cm[5])
  dwg.add(dwg.text(text, insert=(x, y), fill="blue"))
 
 

pypdf/__init__.py

@@ -10,7 +10,7 @@
 from ._crypt_providers import crypt_provider
 from ._encryption import PasswordType
 from ._merger import PdfFileMerger, PdfMerger
-from ._page import PageObject, Transformation
+from ._page import PageObject, Transformation, mult
 from ._reader import DocumentInformation, PdfFileReader, PdfReader
 from ._version import __version__
 from ._writer import ObjectDeletionFlag, PdfFileWriter, PdfWriter
@@ -31,6 +31,7 @@
 __all__ = [
  "__version__",
  "_debug_versions",
+ "mult",
  "PageRange",
  "PaperSize",
  "DocumentInformation",

pypdf/_page.py

@@ -1921,18 +1921,17 @@
  # are strings where the byte->string encoding was unknown, so adding
  # them to the text here would be gibberish.
 
- cm_prev: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
  cm_matrix: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
  cm_stack = []
  tm_matrix: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
- tm_prev: List[float] = [
-  1.0,
-   0.0,
-   0.0,
- 1.0,
-  0.0,
-   0.0,
- ] # will store previous tm_matrix
+
+ # cm/tm_prev stores the last modified matrices can be an intermediate position
+ cm_prev: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
+ tm_prev: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
+
+ # memo_cm/tm will be used to store the position at the beginning of building the text
+ memo_cm: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
+ memo_tm: List[float] = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
  char_scale = 1.0
  space_scale = 1.0
  _space_width: float = 500.0 # will be set correctly at first Tf
@@ -1943,9 +1942,9 @@
  return _space_width / 1000.0
 
  def process_operation(operator: bytes, operands: List) -> None:
- nonlocal cm_matrix, cm_stack, tm_matrix, cm_prev, tm_prev, output, text
+ nonlocal cm_matrix, cm_stack, tm_matrix, cm_prev, tm_prev, memo_cm, memo_tm
  nonlocal char_scale, space_scale, _space_width, TL, font_size, cmap
- nonlocal orientations, rtl_dir, visitor_text
+ nonlocal orientations, rtl_dir, visitor_text, output, text
  global CUSTOM_RTL_MIN, CUSTOM_RTL_MAX, CUSTOM_RTL_SPECIAL_CHARS
 
  check_crlf_space: bool = False
@@ -1954,14 +1953,18 @@
  tm_matrix = [1.0, 0.0, 0.0, 1.0, 0.0, 0.0]
  output += text
  if visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(text, memo_cm, memo_tm, cmap[3], font_size)
  text = ""
+ memo_cm = cm_matrix.copy()
+ memo_tm = tm_matrix.copy()
  return None
  elif operator == b"ET":
  output += text
  if visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(text, memo_cm, memo_tm, cmap[3], font_size)
  text = ""
+ memo_cm = cm_matrix.copy()
+ memo_tm = tm_matrix.copy()
  # table 4.7 "Graphics state operators", page 219
  # cm_matrix calculation is a reserved for the moment
  elif operator == b"q":
@@ -1992,7 +1995,7 @@
  elif operator == b"cm":
  output += text
  if visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(text, memo_cm, memo_tm, cmap[3], font_size)
  text = ""
  cm_matrix = mult(
  [
@@ -2005,6 +2008,8 @@
  ],
  cm_matrix,
  )
+ memo_cm = cm_matrix.copy()
+ memo_tm = tm_matrix.copy()
  # Table 5.2 page 398
  elif operator == b"Tz":
  char_scale = float(operands[0]) / 100.0
@@ -2016,8 +2021,10 @@
  if text != "":
  output += text # .translate(cmap)
  if visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(text, memo_cm, memo_tm, cmap[3], font_size)
  text = ""
+ memo_cm = cm_matrix.copy()
+ memo_tm = tm_matrix.copy()
  try:
  # charMapTuple: font_type, float(sp_width / 2), encoding,
  # map_dict, font-dictionary
@@ -2088,17 +2095,19 @@
  try:
  text, output, cm_prev, tm_prev = crlf_space_check(
  text,
- cm_prev,
- tm_prev,
- cm_matrix,
- tm_matrix,
+ (cm_prev, tm_prev),
+ (cm_matrix, tm_matrix),
+ (memo_cm, memo_tm),
  cmap,
  orientations,
  output,
  font_size,
  visitor_text,
  current_spacewidth(),
  )
+ if text == "":
+ memo_cm = cm_matrix.copy()
+ memo_tm = tm_matrix.copy()
  except OrientationNotFoundError:
  return None
 
@@ -2130,12 +2139,18 @@
  elif operator == b"Do":
  output += text
  if visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(text, memo_cm, memo_tm, cmap[3], font_size)
  try:
  if output[-1] != "\n":
  output += "\n"
  if visitor_text is not None:
- visitor_text("\n", cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(
+ "\n",
+ memo_cm,
+ memo_tm,
+ cmap[3],
+ font_size,
+ )
  except IndexError:
  pass
  try:
@@ -2151,21 +2166,30 @@
  )
  output += text
  if visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(
+ text,
+ memo_cm,
+ memo_tm,
+ cmap[3],
+ font_size,
+ )
  except Exception:
  logger_warning(
  f" impossible to decode XFormObject {operands[0]}",
  __name__,
  )
  finally:
  text = ""
+ memo_cm = cm_matrix.copy()
+ memo_tm = tm_matrix.copy()
+
  else:
  process_operation(operator, operands)
  if visitor_operand_after is not None:
  visitor_operand_after(operator, operands, cm_matrix, tm_matrix)
  output += text # just in case of
  if text != "" and visitor_text is not None:
- visitor_text(text, cm_matrix, tm_matrix, cmap[3], font_size)
+ visitor_text(text, memo_cm, memo_tm, cmap[3], font_size)
  return output
 
  def extract_text(

pypdf/_text_extraction/__init__.py

@@ -87,10 +87,9 @@ def orient(m: List[float]) -> int:
 
 def crlf_space_check(
  text: str,
- cm_prev: List[float],
- tm_prev: List[float],
- cm_matrix: List[float],
- tm_matrix: List[float],
+ cmtm_prev: Tuple[List[float], List[float]],
+ cmtm_matrix: Tuple[List[float], List[float]],
+ memo_cmtm: Tuple[List[float], List[float]],
  cmap: Tuple[
  Union[str, Dict[int, str]], Dict[str, str], str, Optional[DictionaryObject]
  ],
@@ -100,13 +99,21 @@ def crlf_space_check(
  visitor_text: Optional[Callable[[Any, Any, Any, Any, Any], None]],
  spacewidth: float,
 ) -> Tuple[str, str, List[float], List[float]]:
+ cm_prev = cmtm_prev[0]
+ tm_prev = cmtm_prev[1]
+ cm_matrix = cmtm_matrix[0]
+ tm_matrix = cmtm_matrix[1]
+ memo_cm = memo_cmtm[0]
+ memo_tm = memo_cmtm[1]
+
  m_prev = mult(tm_prev, cm_prev)
  m = mult(tm_matrix, cm_matrix)
  orientation = orient(m)
  delta_x = m[4] - m_prev[4]
  delta_y = m[5] - m_prev[5]
  k = math.sqrt(abs(m[0] * m[3]) + abs(m[1] * m[2]))
  f = font_size * k
+ cm_prev = m
  if orientation not in orientations:
  raise OrientationNotFoundError
  try:
@@ -117,8 +124,8 @@ def crlf_space_check(
  if visitor_text is not None:
  visitor_text(
  text + "\n",
- cm_prev,
- tm_prev,
+ memo_cm,
+ memo_tm,
  cmap[3],
  font_size,
  )
@@ -136,8 +143,8 @@ def crlf_space_check(
  if visitor_text is not None:
  visitor_text(
  text + "\n",
- cm_prev,
- tm_prev,
+ memo_cm,
+ memo_tm,
  cmap[3],
  font_size,
  )
@@ -155,8 +162,8 @@ def crlf_space_check(
  if visitor_text is not None:
  visitor_text(
  text + "\n",
- cm_prev,
- tm_prev,
+ memo_cm,
+ memo_tm,
  cmap[3],
  font_size,
  )
@@ -174,8 +181,8 @@ def crlf_space_check(
  if visitor_text is not None:
  visitor_text(
  text + "\n",
- cm_prev,
- tm_prev,
+ memo_cm,
+ memo_tm,
  cmap[3],
  font_size,
  )

tests/test_page.py

@@ -1288,3 +1288,81 @@ def test_get_contents_from_nullobject():
  p = writer.add_blank_page(100, 100)
  p[NameObject("/Contents")] = writer._add_object(NullObject())
  p.get_contents()
+
+
+@pytest.mark.enable_socket()
+def test_pos_text_in_textvisitor():
+ """See #2200"""
+ url = "https://github.com/py-pdf/pypdf/files/12675974/page_178.pdf"
+ name = "test_text_pos.pdf"
+ reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+ p = ()
+
+ def visitor_body2(text, cm, tm, fontdict, fontsize) -> None:
+ nonlocal p
+ if text.startswith("5425."):
+ p = (tm[4], tm[5])
+
+ reader.pages[0].extract_text(visitor_text=visitor_body2)
+ assert abs(p[0] - 323.5) < 0.1
+ assert abs(p[1] - 457.4) < 0.1
+
+
+@pytest.mark.enable_socket()
+def test_pos_text_in_textvisitor2():
+ """See #2075"""
+ url = "https://github.com/py-pdf/pypdf/files/12318042/LegIndex-page6.pdf"
+ name = "LegIndex-page6.pdf"
+ reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+ x_lvl = 26
+ lst = []
+
+ def visitor_lvl(text, cm, tm, fontdict, fontsize) -> None:
+ nonlocal x_lvl, lst
+ if abs(tm[4] - x_lvl) < 2 and tm[5] < 740 and tm[5] > 210:
+ lst.append(text.strip(" \n"))
+
+ reader.pages[0].extract_text(visitor_text=visitor_lvl)
+ assert lst == [
+ "ACUPUNCTURE BOARD",
+ "ACUPUNCTURISTS AND ACUPUNCTURE",
+ "ADMINISTRATIVE LAW AND PROCEDURE",
+ "ADMINISTRATIVE LAW, OFFICE OF",
+ "ADOPTION",
+ "ADULT EDUCATION",
+ "ADVERTISING. See also MARKETING; and particular subject matter (e.g.,",
+ ]
+ x_lvl = 35
+ lst = []
+ reader.pages[0].extract_text(visitor_text=visitor_lvl)
+ assert lst == [
+ "members, AB 1264",
+ "assistants, acupuncture, AB 1264",
+ "complaints, investigations, etc., AB 1264",
+ "day, california acupuncture, HR 48",
+ "massage services, asian, AB 1264",
+ "supervising acupuncturists, AB 1264",
+ "supportive acupuncture services, basic, AB 1264",
+ "rules and regulations—",
+ "professional assistants and employees: employment and compensation, AB 916",
+ "adults, adoption of, AB 1756",
+ "agencies, organizations, etc.: requirements, prohibitions, etc., SB 807",
+ "assistance programs, adoption: nonminor dependents, SB 9",
+ "birth certificates, AB 1302",
+ "contact agreements, postadoption—",
+ "facilitators, adoption, AB 120",
+ "failed adoptions: reproductive loss leave, SB 848",
+ "hearings, adoption finalization: remote proceedings, technology, etc., SB 21",
+ "native american tribes, AB 120",
+ "parental rights, reinstatement of, AB 20",
+ "parents, prospective adoptive: criminal background checks, SB 824",
+ "services, adult educational, SB 877",
+ "week, adult education, ACR 31",
+ "alcoholic beverages: tied-house restrictions, AB 546",
+ "campaign re social equity, civil rights, etc., SB 447",
+ "cannabis, AB 794",
+ "elections. See ELECTIONS.",
+ "false, misleading, etc., advertising—",
+ "hotels, short-term rentals, etc., advertised rates: mandatory fee disclosures, SB 683",
+ "housing rental properties advertised rates: disclosures, SB 611",
+ ]