DOC: Add some references to ISO 32000-2:2020 (PDF 2.0) (#2623)

Add some references to ISO 32000-2:2020 (PDF 2.0)
Also reorder to match the PDF 2.0 table order.
Add fields to PageLayouts and CatalogDictionary.

Author: j-t-1

pypdf/constants.py

@@ -6,6 +6,8 @@
 PDF Reference, third edition, Version 1.4, 2001. ISBN 0-201-75839-3.
 
 PDF Reference, sixth edition, Version 1.7, 2006.
+
+ISO 32000-2:2020 (PDF 2.0).
 """
 
 from enum import IntFlag, auto
@@ -41,7 +43,8 @@ class EncryptionDictAttributes:
     """
     Additional encryption dictionary entries for the standard security handler.
 
-    TABLE 3.19, Page 122
+    Table 3.19, Page 122.
+    Table 21 of the 2.0 manual.
     """
 
     R = "/R"  # number, required; revision of the standard security handler
@@ -52,7 +55,10 @@ class EncryptionDictAttributes:
 
 
 class UserAccessPermissions(IntFlag):
-    """TABLE 3.20 User access permissions."""
+    """
+    Table 3.20 User access permissions.
+    Table 22 of the 2.0 manual.
+    """
 
     R1 = 1
     R2 = 2
@@ -131,8 +137,10 @@ def all(cls) -> "UserAccessPermissions":
 
 class Resources:
     """
-    TABLE 3.30 Entries in a resource dictionary.
+    Table 3.30 Entries in a resource dictionary.
     used to be Ressources
+
+    Table 34 in the 2.0 reference.
     """
 
     EXT_G_STATE = "/ExtGState"  # dictionary, optional
@@ -202,16 +210,22 @@ def PROPERTIES(cls) -> str:
 
 
 class PagesAttributes:
-    """Page Attributes, Table 6.2, Page 52."""
+    """
+    Page Attributes, Table 6.2, Page 52.
+    Page tree node, Table 30 in the 2.0 reference.
+    """
 
     TYPE = "/Type"  # name, required; must be /Pages
+    PARENT = "/Parent"  # dictionary, required; indirect reference to pages object
     KIDS = "/Kids"  # array, required; List of indirect references
     COUNT = "/Count"  # integer, required; the number of all nodes und this node
-    PARENT = "/Parent"  # dictionary, required; indirect reference to pages object
 
 
 class PageAttributes:
-    """TABLE 3.27 Entries in a page object."""
+    """
+    Table 3.27 Entries in a page object.
+    Table 31 in the 2.0 reference.
+    """
 
     TYPE = "/Type"  # name, required; must be /Page
     PARENT = "/Parent"  # dictionary, required; a pages object
@@ -247,7 +261,7 @@ class PageAttributes:
 
 
 class FileSpecificationDictionaryEntries:
-    """TABLE 3.41 Entries in a file specification dictionary."""
+    """Table 3.41 Entries in a file specification dictionary."""
 
     Type = "/Type"
     FS = "/FS"  # The name of the file system to be used to interpret this file specification
@@ -265,7 +279,10 @@ class FileSpecificationDictionaryEntries:
 
 
 class StreamAttributes:
-    """Table 4.2."""
+    """
+    Table 4.2.
+    Table 5 in the 2.0 reference.
+    """
 
     LENGTH = "/Length"  # integer, required
     FILTER = "/Filter"  # name or array of names, optional
@@ -276,7 +293,9 @@ class FilterTypes:
     """
     Table 4.3 of the 1.4 Manual.
 
-    Page 354 of the 1.7 Manual
+    Page 354 of the 1.7 Manual.
+
+    Table 6 of the 2.0 manual.
     """
 
     ASCII_HEX_DECODE = "/ASCIIHexDecode"  # abbreviation: AHx
@@ -290,7 +309,10 @@ class FilterTypes:
 
 
 class FilterTypeAbbreviations:
-    """Table 4.44 of the 1.7 Manual (page 353ff)."""
+    """
+    Table 4.44 of the 1.7 Manual (page 353ff).
+    Table 92 of the 2.0 manual.
+    """
 
     AHx = "/AHx"
     A85 = "/A85"
@@ -302,17 +324,23 @@ class FilterTypeAbbreviations:
 
 
 class LzwFilterParameters:
-    """Table 4.4."""
+    """
+    Table 4.4.
+    Table 8 in the 2.0 reference.
+    """
 
     PREDICTOR = "/Predictor"  # integer
-    COLUMNS = "/Columns"  # integer
     COLORS = "/Colors"  # integer
     BITS_PER_COMPONENT = "/BitsPerComponent"  # integer
+    COLUMNS = "/Columns"  # integer
     EARLY_CHANGE = "/EarlyChange"  # integer
 
 
 class CcittFaxDecodeParameters:
-    """Table 4.5."""
+    """
+    Table 4.5.
+    Table 11 in the 2.0 reference.
+    """
 
     K = "/K"  # integer
     END_OF_LINE = "/EndOfLine"  # boolean
@@ -325,7 +353,7 @@ class CcittFaxDecodeParameters:
 
 
 class ImageAttributes:
-    """Table 4.39 Pdf Reference 1.7 page 340+"""
+    """Table 4.39 PDF Reference 1.7 page 340+"""
 
     TYPE = "/Type"  # name, required; must be /XObject
     SUBTYPE = "/Subtype"  # name, required; must be /Image
@@ -376,7 +404,7 @@ class GoToActionArguments:
 
 
 class AnnotationDictionaryAttributes:
-    """TABLE 8.15 Entries common to all annotation dictionaries."""
+    """Table 8.15 Entries common to all annotation dictionaries."""
 
     Type = "/Type"
     Subtype = "/Subtype"
@@ -407,7 +435,7 @@ class InteractiveFormDictEntries:
 
 
 class FieldDictionaryAttributes:
-    """TABLE 8.69 Entries common to all field dictionaries (PDF 1.7 reference)."""
+    """Table 8.69 Entries common to all field dictionaries (PDF 1.7 reference)."""
 
     FT = "/FT"  # name, required for terminal fields
     Parent = "/Parent"  # dictionary, required for children
@@ -503,7 +531,7 @@ def attributes_dict(cls) -> Dict[str, str]:
 
 
 class CheckboxRadioButtonAttributes:
-    """TABLE 8.76 Field flags common to all field types."""
+    """Table 8.76 Field flags common to all field types."""
 
     Opt = "/Opt"  # Options, Optional
 
@@ -542,15 +570,15 @@ def attributes_dict(cls) -> Dict[str, str]:
 
 
 class FieldFlag(IntFlag):
-    """TABLE 8.70 Field flags common to all field types."""
+    """Table 8.70 Field flags common to all field types."""
 
     READ_ONLY = 1
     REQUIRED = 2
     NO_EXPORT = 4
 
 
 class DocumentInformationAttributes:
-    """TABLE 10.2 Entries in the document information dictionary."""
+    """Table 10.2 Entries in the document information dictionary."""
 
     TITLE = "/Title"  # text string, optional
     AUTHOR = "/Author"  # text string, optional
@@ -564,12 +592,17 @@ class DocumentInformationAttributes:
 
 
 class PageLayouts:
-    """Page 84, PDF 1.4 reference."""
+    """
+    Page 84, PDF 1.4 reference.
+    Page 115, PDF 2.0 reference.
+    """
 
     SINGLE_PAGE = "/SinglePage"
     ONE_COLUMN = "/OneColumn"
     TWO_COLUMN_LEFT = "/TwoColumnLeft"
     TWO_COLUMN_RIGHT = "/TwoColumnRight"
+    TWO_PAGE_LEFT = "/TwoPageLeft"  # (PDF 1.5)
+    TWO_PAGE_RIGHT = "/TwoPageRight"  # (PDF 1.5)
 
 
 class GraphicsStateParameters:
@@ -605,10 +638,14 @@ class GraphicsStateParameters:
 
 
 class CatalogDictionary:
-    """Table 3.25 in the 1.7 reference."""
+    """
+    Table 3.25 in the 1.7 reference.
+    Table 29 in the 2.0 reference.
+    """
 
     TYPE = "/Type"  # name, required; must be /Catalog
     VERSION = "/Version"  # name
+    EXTENSIONS = "/Extensions"  # dictionary, optional; ISO 32000-1
     PAGES = "/Pages"  # dictionary, required
     PAGE_LABELS = "/PageLabels"  # number tree, optional
     NAMES = "/Names"  # dictionary, optional
@@ -635,6 +672,9 @@ class CatalogDictionary:
     REQUIREMENTS = "/Requirements"  # array, optional
     COLLECTION = "/Collection"  # dictionary, optional
     NEEDS_RENDERING = "/NeedsRendering"  # boolean, optional
+    DSS = "/DSS"  # dictionary, optional
+    AF = "/AF"  # array of dictionaries, optional
+    D_PART_ROOT = "/DPartRoot"  # dictionary, optional
 
 
 class OutlineFontFlag(IntFlag):
@@ -645,17 +685,20 @@ class OutlineFontFlag(IntFlag):
 
 
 class PageLabelStyle:
-    """Table 8.10 in the 1.7 reference."""
+    """
+    Table 8.10 in the 1.7 reference.
+    Table 161 in the 2.0 reference.
+    """
 
-    DECIMAL = "/D"  # Decimal arabics
-    LOWERCASE_ROMAN = "/r"  # Lowercase roman numbers
-    UPPERCASE_ROMAN = "/R"  # Uppercase roman numbers
-    LOWERCASE_LETTER = "/a"  # Lowercase letters
+    DECIMAL = "/D"  # Decimal Arabic numerals
+    UPPERCASE_ROMAN = "/R"  # Uppercase Roman numerals
+    LOWERCASE_ROMAN = "/r"  # Lowercase Roman numerals
     UPPERCASE_LETTER = "/A"  # Uppercase letters
+    LOWERCASE_LETTER = "/a"  # Lowercase letters
 
 
 class AnnotationFlag(IntFlag):
-    """See 12.5.3 "Annotation Flags"."""
+    """See §12.5.3 "Annotation Flags"."""
 
     INVISIBLE = 1
     HIDDEN = 2