ENH: Ease access to ViewerPreferences

pypdf/_reader.py

@@ -103,6 +103,7 @@
  PdfObject,
  TextStringObject,
  TreeObject,
+ ViewerPreferences,
  read_object,
 )
 from .types import OutlineType, PagemodeType
@@ -293,6 +294,19 @@ class PdfReader:
  Defaults to ``None``
  """
 
+ @property
+ def viewer_preferences(self) -> Optional[ViewerPreferences]:
+ """Returns the existing ViewerPreferences as a overloaded dictionniary."""
+ o = cast(DictionaryObject, self.trailer["/Root"]).get(
+ CD.VIEWER_PREFERENCES, None
+ )
+ if o is None:
+ return None
+ o = o.get_object()
+ if not isinstance(o, ViewerPreferences):
+ o = ViewerPreferences(o)
+ return o
+
  def __init__(
  self,
  stream: Union[StrByteType, Path],

pypdf/_writer.py

@@ -82,6 +82,7 @@
  TypFitArguments,
  UserAccessPermissions,
 )
+from .constants import CatalogDictionary as CD
 from .constants import Core as CO
 from .constants import (
  FieldDictionaryAttributes as FA,
@@ -110,6 +111,7 @@
  StreamObject,
  TextStringObject,
  TreeObject,
+ ViewerPreferences,
  create_string_object,
  hex_to_rgb,
 )
@@ -367,6 +369,26 @@ def set_need_appearances_writer(self, state: bool = True) -> None:
  f"set_need_appearances_writer({state}) catch : {exc}", __name__
  )
 
+ @property
+ def viewer_preferences(self) -> Optional[ViewerPreferences]:
+ """Returns the existing ViewerPreferences as a overloaded dictionniary."""
+ o = cast(DictionaryObject, self._root_object).get(CD.VIEWER_PREFERENCES, None)
+ if o is None:
+ return None
+ o = o.get_object()
+ if not isinstance(o, ViewerPreferences):
+ o = ViewerPreferences(o)
+ if hasattr(o, "indirect_reference"):
+ self._replace_object(o.indirect_reference, o)
+ else:
+ self._root_object[NameObject(CD.VIEWER_PREFERENCES)] = o
+ return o
+
+ def create_viewer_preference(self) -> ViewerPreferences:
+ o = ViewerPreferences()
+ self._root_object[NameObject(CD.VIEWER_PREFERENCES)] = self._add_object(o)
+ return o
+
  def add_page(
  self,
  page: PageObject,

pypdf/generic/__init__.py

@@ -67,6 +67,7 @@
  read_hex_string_from_stream,
  read_string_from_stream,
 )
+from ._viewerpref import ViewerPreferences
 
 
 def readHexStringFromStream(
@@ -443,6 +444,7 @@ def link(
  "RectangleObject",
  "Field",
  "Destination",
+ "ViewerPreferences",
  # --- More specific stuff
  # Outline
  "OutlineItem",

pypdf/generic/_viewerpref.py

@@ -0,0 +1,154 @@
+# Copyright (c) 2023, Pubpub-ZZ
+#
+# 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.
+
+from typing import (
+ Any,
+ List,
+ Optional,
+)
+
+from ._base import BooleanObject, NameObject, NumberObject
+from ._data_structures import ArrayObject, DictionaryObject
+
+f_obj = BooleanObject(False)
+
+
+class ViewerPreferences(DictionaryObject):
+ def _get_bool(self, key: str, deft: Optional[BooleanObject]) -> BooleanObject:
+ return self.get(key, deft)
+
+ def _set_bool(self, key: str, v: bool) -> None:
+ self[NameObject(key)] = BooleanObject(v is True)
+
+ def _get_name(self, key: str, deft: Optional[NameObject]) -> Optional[NameObject]:
+ return self.get(key, deft)
+
+ def _set_name(self, key: str, lst: List[str], v: NameObject) -> None:
+ if v[0] != "/":
+ raise ValueError(f"{v} is not starting with '/'")
+ if lst != [] and v not in lst:
+ raise ValueError(f"{v} is not par of acceptable values")
+ self[NameObject(key)] = NameObject(v)
+
+ def _get_arr(self, key: str, deft: Optional[List[Any]]) -> NumberObject:
+ return self.get(key, None if deft is None else ArrayObject(deft))
+
+ def _set_arr(self, key: str, v: Optional[ArrayObject]) -> None:
+ if not isinstance(v, ArrayObject):
+ raise ValueError("ArrayObject is expected")
+ self[NameObject(key)] = v
+
+ def _get_int(self, key: str, deft: Optional[NumberObject]) -> NumberObject:
+ return self.get(key, deft)
+
+ def _set_int(self, key: str, v: int) -> None:
+ self[NameObject(key)] = NumberObject(v)
+
+ def __new__(cls: Any, value: Any = None) -> "ViewerPreferences":
+ def _add_prop_bool(key: str, deft: Optional[BooleanObject]) -> property:
+ return property(
+ lambda self: self._get_bool(key, deft),
+ lambda self, v: self._set_bool(key, v),
+ None,
+ f"""
+ Returns/Modify the status of {key}, Returns {deft} if not defined
+ """,
+ )
+
+ def _add_prop_name(
+ key: str, lst: List[str], deft: Optional[NameObject]
+ ) -> property:
+ return property(
+ lambda self: self._get_name(key, deft),
+ lambda self, v: self._set_name(key, lst, v),
+ None,
+ f"""
+ Returns/Modify the status of {key}, Returns {deft} if not defined.
+ Acceptable values: {lst}
+ """,
+ )
+
+ def _add_prop_arr(key: str, deft: Optional[ArrayObject]) -> property:
+ return property(
+ lambda self: self._get_arr(key, deft),
+ lambda self, v: self._set_arr(key, v),
+ None,
+ f"""
+ Returns/Modify the status of {key}, Returns {deft} if not defined
+ """,
+ )
+
+ def _add_prop_int(key: str, deft: Optional[int]) -> property:
+ return property(
+ lambda self: self._get_int(key, deft),
+ lambda self, v: self._set_int(key, v),
+ None,
+ f"""
+ Returns/Modify the status of {key}, Returns {deft} if not defined
+ """,
+ )
+
+ cls.hide_toolbar = _add_prop_bool("/HideToolbar", f_obj)
+ cls.hide_menubar = _add_prop_bool("/HideMenubar", f_obj)
+ cls.hide_windowui = _add_prop_bool("/HideWindowUI", f_obj)
+ cls.fit_window = _add_prop_bool("/FitWindow", f_obj)
+ cls.center_window = _add_prop_bool("/CenterWindow", f_obj)
+ cls.display_doctitle = _add_prop_bool("/DisplayDocTitle", f_obj)
+
+ cls.non_fullscreen_pagemode = _add_prop_name(
+ "/NonFullScreenPageMode",
+ ["/UseNone", "/UseOutlines", "/UseThumbs", "/UseOC"],
+ NameObject("/UseNone"),
+ )
+ cls.direction = _add_prop_name(
+ "/Direction", ["/L2R", "/R2L"], NameObject("/L2R")
+ )
+ cls.view_area = _add_prop_name("/ViewArea", [], None)
+ cls.view_clip = _add_prop_name("/ViewClip", [], None)
+ cls.print_area = _add_prop_name("/PrintArea", [], None)
+ cls.print_clip = _add_prop_name("/PrintClip", [], None)
+ cls.print_scaling = _add_prop_name("/PrintScaling", [], None)
+ cls.duplex = _add_prop_name(
+ "/Duplex", ["/Simplex", "/DuplexFlipShortEdge", "/DuplexFlipLongEdge"], None
+ )
+ cls.pick_tray_by_pdfsize = _add_prop_bool("/PickTrayByPDFSize", None)
+ cls.print_pagerange = _add_prop_arr("/PrintPageRange", None)
+ cls.num_copies = _add_prop_int("/NumCopies", None)
+
+ # still to be done /PrintPageRange and /NumCopies
+
+ return DictionaryObject.__new__(cls)
+
+ def __init__(self, obj: Optional[DictionaryObject] = None) -> None:
+ super().__init__(self)
+ if obj is not None:
+ self.update(obj.items())
+ try:
+ self.indirect_reference = obj.indirect_reference # type: ignore
+ except AttributeError:
+ pass

tests/test_writer.py

@@ -1675,3 +1675,68 @@ def test_damaged_pdf_length_returning_none():
  reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
  writer = PdfWriter()
  writer.append(reader)
+
+
+@pytest.mark.enable_socket()
+def test_viewerpreferences():
+ """
+ Add Tests for ViewerPreferences
+ https://github.com/py-pdf/pypdf/issues/140#issuecomment-1685380549
+ """
+ url = "https://github.com/py-pdf/pypdf/files/9175966/2015._pb_decode_pg0.pdf"
+ name = "2015._pb_decode_pg0.pdf"
+ reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+ v = reader.viewer_preferences
+ assert v.center_window == True # noqa: E712
+ writer = PdfWriter(clone_from=reader)
+ v = writer.viewer_preferences
+ assert v.center_window == True # noqa: E712
+ v.center_window = False
+ assert (
+ writer._root_object["/ViewerPreferences"]["/CenterWindow"]
+ == False # noqa: E712
+ )
+ assert v.print_area == "/CropBox"
+ with pytest.raises(ValueError):
+ v.non_fullscreen_pagemode = "toto"
+ with pytest.raises(ValueError):
+ v.non_fullscreen_pagemode = "/toto"
+ v.non_fullscreen_pagemode = "/UseOutlines"
+ assert (
+ writer._root_object["/ViewerPreferences"]["/NonFullScreenPageMode"]
+ == "/UseOutlines"
+ )
+ writer = PdfWriter(clone_from=reader)
+ v = writer.viewer_preferences
+ assert v.center_window == True # noqa: E712
+ v.center_window = False
+ assert (
+ writer._root_object["/ViewerPreferences"]["/CenterWindow"]
+ == False # noqa: E712
+ )
+
+ writer = PdfWriter(clone_from=reader)
+ writer._root_object[NameObject("/ViewerPreferences")] = writer._add_object(
+ writer._root_object["/ViewerPreferences"]
+ )
+ v = writer.viewer_preferences
+ v.center_window = False
+ assert (
+ writer._root_object["/ViewerPreferences"]["/CenterWindow"]
+ == False # noqa: E712
+ )
+ v.num_copies = 1
+ assert v.num_copies == 1
+ assert v.print_pagerange is None
+ with pytest.raises(ValueError):
+ v.print_pagerange = "toto"
+ v.print_pagerange = ArrayObject()
+ assert len(v.print_pagerange) == 0
+
+ writer.create_viewer_preference()
+ assert len(writer._root_object["/ViewerPreferences"]) == 0
+
+ del reader.trailer["/Root"]["/ViewerPreferences"]
+ assert reader.viewer_preferences is None
+ writer = PdfWriter(clone_from=reader)
+ assert writer.viewer_preferences is None