DOC: Update PDF standard references (#2640)

Author: j-t-1

docs/user/pdf-version-support.md

@@ -9,8 +9,8 @@ PDF comes in the following versions:
 * 2001: 1.4
 * 2003: 1.5
 * 2004: 1.6
-* 2006 - 2012: 1.7, ISO 32000-1:2008
-* 2017: 2.0
+* 2008: 1.7, ISO 32000-1:2008
+* 2017: 2.0, ISO 32000-2:2017
 
 The general format didn't change, but new features got added. It can be that
 pypdf can do the operations you want on PDF 2.0 files without fully supporting

docs/user/robustness.md

@@ -1,7 +1,7 @@
 # Robustness and strict=False
 
-PDF is [specified in various versions](https://www.pdfa.org/resource/pdf-specification-index/).
-The specification of PDF 1.7 has 978 pages. This length makes it hard to get
+PDF is [specified in various versions](https://pdfa.org/resource/pdf-specification-archive/).
+The specification of PDF 2.0 has 1003 pages. This length makes it hard to get
 everything right. As a consequence, a lot of PDF files are not strictly following the
 specification.
 

pypdf/_writer.py

@@ -1171,7 +1171,7 @@ def encrypt(
                 encryption.  When false, 40bit encryption will be used.
                 By default, this flag is on.
             permissions_flag: permissions as described in
-                TABLE 3.20 of the PDF 1.7 specification. A bit value of 1 means
+                Table 3.20 of the PDF 1.7 specification. A bit value of 1 means
                 the permission is grantend.
                 Hence an integer value of -1 will set all flags.
                 Bit position 3 is for printing, 4 is for modifying content,
@@ -1481,7 +1481,7 @@ def get_reference(self, obj: PdfObject) -> IndirectObject:
 
     def get_outline_root(self) -> TreeObject:
         if CO.OUTLINES in self._root_object:
-            # TABLE 3.25 Entries in the catalog dictionary
+            # Table 3.25 Entries in the catalog dictionary
             outline = cast(TreeObject, self._root_object[CO.OUTLINES])
             if not isinstance(outline, TreeObject):
                 t = TreeObject(outline)
@@ -1509,7 +1509,7 @@ def get_threads_root(self) -> ArrayObject:
             ``/I`` properties.
         """
         if CO.THREADS in self._root_object:
-            # TABLE 3.25 Entries in the catalog dictionary
+            # Table 3.25 Entries in the catalog dictionary
             threads = cast(ArrayObject, self._root_object[CO.THREADS])
         else:
             threads = ArrayObject()

pypdf/constants.py

@@ -1,13 +1,14 @@
 """
-See Portable Document Format Reference Manual, 1993. ISBN 0-201-62628-4.
+PDF Specification Archive
+https://pdfa.org/resource/pdf-specification-archive/
 
-See https://ia802202.us.archive.org/8/items/pdfy-0vt8s-egqFwDl7L2/PDF%20Reference%201.0.pdf
+Portable Document Format Reference Manual, 1993. ISBN 0-201-62628-4
+https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/pdfreference1.0.pdf
 
-PDF Reference, third edition, Version 1.4, 2001. ISBN 0-201-75839-3.
+ISO 32000-1:2008 (PDF 1.7)
+https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf
 
-PDF Reference, sixth edition, Version 1.7, 2006.
-
-ISO 32000-2:2020 (PDF 2.0).
+ISO 32000-2:2020 (PDF 2.0)
 """
 
 from enum import IntFlag, auto
@@ -290,13 +291,7 @@ class StreamAttributes:
 
 
 class FilterTypes:
-    """
-    Table 4.3 of the 1.4 Manual.
-
-    Page 354 of the 1.7 Manual.
-
-    Table 6 of the 2.0 manual.
-    """
+    """§7.4 of the 1.7 and 2.0 references."""
 
     ASCII_HEX_DECODE = "/ASCIIHexDecode"  # abbreviation: AHx
     ASCII_85_DECODE = "/ASCII85Decode"  # abbreviation: A85
@@ -309,10 +304,7 @@ class FilterTypes:
 
 
 class FilterTypeAbbreviations:
-    """
-    Table 4.44 of the 1.7 Manual (page 353ff).
-    Table 92 of the 2.0 manual.
-    """
+    """§8.9.7 of the 1.7 and 2.0 references."""
 
     AHx = "/AHx"
     A85 = "/A85"
@@ -353,7 +345,7 @@ class CcittFaxDecodeParameters:
 
 
 class ImageAttributes:
-    """Table 4.39 PDF Reference 1.7 page 340+"""
+    """§11.6.5 of the 1.7 and 2.0 references."""
 
     TYPE = "/Type"  # name, required; must be /XObject
     SUBTYPE = "/Subtype"  # name, required; must be /Image
@@ -638,10 +630,7 @@ class GraphicsStateParameters:
 
 
 class CatalogDictionary:
-    """
-    Table 3.25 in the 1.7 reference.
-    Table 29 in the 2.0 reference.
-    """
+    """§7.7.2 of the 1.7 and 2.0 references."""
 
     TYPE = "/Type"  # name, required; must be /Catalog
     VERSION = "/Version"  # name

pypdf/generic/_data_structures.py

@@ -1425,7 +1425,7 @@ class Destination(TreeObject):
     """
     A class representing a destination within a PDF file.
 
-    See section 8.2.1 of the PDF 1.6 reference.
+    See section 12.3.2 of the PDF 2.0 reference.
 
     Args:
         title: Title of this destination.