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merge pull request #84 from BobLd/master

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add basic bookmarks extraction capabilities.
This commit is contained in:
Eliot Jones
2019-12-04 14:24:10 +00:00
committed by GitHub
parent a967e0898a 9da0623fab
commit 928347bcce
6 changed files with 610 additions and 0 deletions
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68
src/UglyToad.PdfPig/Outline/BookmarkNode.cs Normal file
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using System.Collections.Generic;
using UglyToad.PdfPig.Geometry;
namespace UglyToad.PdfPig.Outline
{
/// <summary>
/// A node in the <see cref="Bookmarks"/> of a PDF document.
/// </summary>
public class BookmarkNode
{
/// <summary>
/// The text displayed for this node.
/// </summary>
public string Title { get; internal set; }
/// <summary>
/// The bookmark's coordinates in the pdf page.
/// </summary>
public PdfPoint TopLeft { get; internal set; }
/// <summary>
/// The bookmark's bounding box in the pdf page.
/// </summary>
public PdfRectangle BoundingBox { get; internal set; }
/// <summary>
/// The node's hierarchical level.
/// </summary>
public int Level { get; internal set; }
/// <summary>
/// The page's number where the bookmark is located.
/// </summary>
public int PageNumber { get; internal set; }
/// <summary>
/// The link to an external source.
/// </summary>
public string ExternalLink { get; internal set; }
/// <summary>
/// True if bookmark refers to an external source.
/// </summary>
public bool IsExternal { get; internal set; }
/// <summary>
/// The bookmark's sub-bookmark.
/// </summary>
public List<BookmarkNode> Children { get; internal set; }
/// <summary>
/// Create a new instance of BookmarkNode.
/// </summary>
public BookmarkNode()
{
Title = string.Empty;
Children = new List<BookmarkNode>();
}
/// <summary>
///
/// </summary>
public override string ToString()
{
return "page #" + PageNumber + ", " + Level + ", " + Title;
}
}
}

42
src/UglyToad.PdfPig/Outline/Bookmarks.cs Normal file
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using System.Collections.Generic;
namespace UglyToad.PdfPig.Outline
{
/// <summary>
/// The bookmarks in a PDF document.
/// </summary>
public class Bookmarks
{
internal Bookmarks(IReadOnlyList<BookmarkNode> tree)
{
Tree = tree;
}
/// <summary>
/// The bookmarks' node tree.
/// </summary>
public IReadOnlyList<BookmarkNode> Tree { get; }
/// <summary>
/// Get all nodes as a list.
/// </summary>
public IReadOnlyList<BookmarkNode> GetNodes()
{
List<BookmarkNode> nodes = new List<BookmarkNode>();
GetNodes(Tree, nodes);
return nodes;
}
private static void GetNodes(IReadOnlyList<BookmarkNode> roots, List<BookmarkNode> nodes)
{
foreach (var node in roots)
{
nodes.Add(node);
if (node.Children.Count > 0)
{
GetNodes(node.Children, nodes);
}
}
}
}
}

470
src/UglyToad.PdfPig/Outline/BookmarksProvider.cs Normal file
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using System;
using UglyToad.PdfPig.Geometry;
using UglyToad.PdfPig.Logging;
using UglyToad.PdfPig.Tokens;
namespace UglyToad.PdfPig.Outline
{
internal class BookmarksProvider
{
private readonly ILog log;
private readonly Structure structure;
public BookmarksProvider(ILog log, Structure structure)
{
this.log = log;
this.structure = structure;
}
/// <summary>
/// Extract bookmarks, if any.
/// </summary>
public Bookmarks GetBookmarks()
{
if (structure.Catalog.CatalogDictionary.Data.TryGetValue(NameToken.Outlines, out IToken outlinesToken))
{
var outlines = this.structure.GetObject(((IndirectReferenceToken)outlinesToken).Data).Data as DictionaryToken;
if (outlines.TryGet(NameToken.First, out IndirectReferenceToken firstToken))
{
var rootNode = new BookmarkNode();
RecursiveBookmarks(firstToken, ref rootNode);
return new Bookmarks(rootNode.Children);
}
}
return null;
}
/// <summary>
/// Extract bookmarks recursively.
/// </summary>
/// <param name="locationToken">The outlines' location token, e.g. First, Next.</param>
/// <param name="node">The current <see cref="BookmarkNode"/>.</param>
private void RecursiveBookmarks(IndirectReferenceToken locationToken, ref BookmarkNode node)
{
// 12.3 Document-Level Navigation
BookmarkNode newNode = new BookmarkNode() { Level = node.Level + 1 };
node.Children.Add(newNode);
var dictionary = structure.GetObject(locationToken.Data).Data as DictionaryToken;
if (dictionary == null)
{
throw new ArgumentNullException("BookmarksProvider.RecursiveBookmarks(): DictionaryToken is null.");
}
// 12.3.3 Document Outline - Title
// (Required) The text that shall be displayed on the screen for this item.
newNode.Title = GetString(NameToken.Title, locationToken);
// 12.3.2 Destinations
if (dictionary.TryGet(NameToken.Dest, out ArrayToken destToken))
{
// 12.3.2.2 Explicit Destinations
GetDestination(destToken, newNode);
}
else if (dictionary.TryGet(NameToken.Dest, out IDataToken<string> destStringToken))
{
// 12.3.2.3 Named Destinations
GetNamedDestination(destStringToken, ref newNode);
}
else if (dictionary.TryGet(NameToken.A, out IToken actionToken))
{
// 12.6 Actions
GetActions(actionToken, ref newNode);
}
else
{
log.Error("BookmarksProvider.RecursiveBookmark(): No 'Dest' or 'Action' token found.");
}
// Look for children
if (dictionary.TryGet(NameToken.First, out IndirectReferenceToken firstToken))
{
RecursiveBookmarks(firstToken, ref newNode);
}
// Move to next
if (dictionary.TryGet(NameToken.Next, out IndirectReferenceToken nextToken))
{
RecursiveBookmarks(nextToken, ref node);
}
}
private string GetString(NameToken nameToken, IToken locationToken)
{
if (locationToken is IDataToken<string> stringDataToken)
{
return stringDataToken.Data;
}
else if (locationToken is DictionaryToken dictionaryToken)
{
if (dictionaryToken.TryGet(nameToken, out IToken token))
{
return GetString(nameToken, token);
}
else
{
throw new NotImplementedException("BookmarksProvider.GetString(): Unknown nameToken '" + nameToken + "'.");
}
}
else if (locationToken is IndirectReferenceToken indirectReferenceToken)
{
var tempToken = structure.GetObject(indirectReferenceToken.Data)?.Data;
if (tempToken == null)
{
throw new ArgumentNullException("BookmarksProvider.GetString(): Cannot find '" + indirectReferenceToken.Data + "'.");
}
return GetString(nameToken, tempToken);
}
else
{
throw new NotImplementedException("BookmarksProvider.GetString(): Unknown string type '" + locationToken.GetType() + "'.");
}
}
private static int ParsePageNumber(string goToStr)
{
if (int.TryParse(System.Text.RegularExpressions.Regex.Match(goToStr, "[0-9]+").Value, out int number))
{
return number + 1;
}
return 0;
}
#region Destinations
private void GetDestination(ArrayToken destToken, BookmarkNode currentNode)
{
if (destToken == null || destToken.Length == 0)
{
throw new ArgumentNullException(nameof(destToken), "BookmarksProvider.GetDestination()");
}
// 12.3.2.2 Explicit Destinations
// Table 151 – Destination syntax
var pageToken = destToken[0];
if (pageToken is IndirectReferenceToken pageIndirectReferenceToken)
{
var pageNumber = structure.Catalog.GetPageByReference(pageIndirectReferenceToken.Data).PageNumber;
if (pageNumber.HasValue)
{
currentNode.PageNumber = pageNumber.Value;
}
else
{
log.Error("BookmarksProvider.GetDestination(): Cannot find page number.");
}
}
else if (pageToken is NumericToken pageNumericToken)
{
currentNode.PageNumber = pageNumericToken.Int + 1;
}
else
{
log.Error("BookmarksProvider.GetDestination(): No page number given in 'Dest': '" + destToken + "'.");
}
var destTypeToken = destToken[1] as NameToken;
if (destTypeToken == null) return;
if (destTypeToken.Equals(NameToken.XYZ))
{
// [page /XYZ left top zoom]
var left = destToken[2] as NumericToken;
var top = destToken[3] as NumericToken;
var zoom = destToken[4] as NumericToken;
currentNode.TopLeft = new PdfPoint(left?.Data ?? 0, top?.Data ?? 0);
}
else if (destTypeToken.Equals(NameToken.Fit))
{
// [page /Fit]
}
else if (destTypeToken.Equals(NameToken.FitH))
{
// [page /FitH top]
var top = destToken[2] as NumericToken;
currentNode.TopLeft = new PdfPoint(0, top?.Data ?? 0);
}
else if (destTypeToken.Equals(NameToken.FitV))
{
// [page /FitV left]
var left = destToken[2] as NumericToken;
currentNode.TopLeft = new PdfPoint(left?.Data ?? 0, 0);
}
else if (destTypeToken.Equals(NameToken.FitR))
{
// [page /FitR left bottom right top]
var left = destToken[2] as NumericToken;
var bottom = destToken[3] as NumericToken;
var right = destToken[4] as NumericToken;
var top = destToken[5] as NumericToken;
currentNode.TopLeft = new PdfPoint(left?.Data ?? 0, top?.Data ?? 0);
currentNode.BoundingBox = new PdfRectangle(left?.Data ?? 0,
bottom?.Data ?? 0,
right?.Data ?? 0,
top?.Data ?? 0);
}
else if (destTypeToken.Equals(NameToken.FitB))
{
// [page /FitB]
}
else if (destTypeToken.Equals(NameToken.FitBH))
{
// [page /FitBH top]
}
else if (destTypeToken.Equals(NameToken.FitBV))
{
// [page /FitBV left]
var top = destToken[2] as NumericToken;
currentNode.TopLeft = new PdfPoint(0, top?.Data ?? 0);
}
else
{
throw new NotImplementedException("BookmarksProvider.GetDestination(): Unknown type '" + destTypeToken + "'.");
}
}
private void GetNamedDestination(IDataToken<string> destStringToken, ref BookmarkNode currentNode)
{
if (destStringToken == null)
{
throw new ArgumentNullException(nameof(destStringToken), "BookmarksProvider.GetNamedDestination()");
}
// 12.3.2.3 Named Destinations
if (structure.Catalog.CatalogDictionary.TryGet(NameToken.Dests, out IndirectReferenceToken destsToken11))
{
// In PDF 1.1, the correspondence between name objects and destinations shall be defined by the
// Dests entry in the document catalogue (see 7.7.2, “Document Catalog”). The value of this entry
// shall be a dictionary in which each key is a destination name and the corresponding value is
// either an array defining the destination, using the syntax shown in Table 151, or a dictionary
// with a D entry whose value is such an array.
throw new NotImplementedException("BookmarksProvider.GetNamedDestination(): PDF 1.1.");
}
else if (structure.Catalog.CatalogDictionary.TryGet(NameToken.Names, out IndirectReferenceToken namesToken))
{
// In PDF 1.2 and later, the correspondence between strings and destinations may alternatively be
// defined by the Dests entry in the document’s name dictionary (see 7.7.4, “Name Dictionary”).
// The value of this entry shall be a name tree (7.9.6, “Name Trees”) mapping name strings to
// destinations. (The keys in the name tree may be treated as text strings for display purposes.)
// The destination value associated with a key in the name tree may be either an array or a
// dictionary, as described in the preceding paragraph.
var namesDictionary = structure.GetObject(namesToken.Data).Data as DictionaryToken;
if (namesDictionary == null)
{
throw new ArgumentNullException(nameof(namesDictionary), "BookmarksProvider.GetNamedDestination()");
}
if (namesDictionary.TryGet(NameToken.Dests, out IndirectReferenceToken destsToken))
{
var destsDictionary = structure.GetObject(destsToken.Data).Data as DictionaryToken;
if (destsDictionary == null)
{
throw new ArgumentNullException(nameof(destsDictionary), "BookmarksProvider.GetNamedDestination()");
}
IToken found = FindInNameTree(destStringToken, destsDictionary);
if (found != null)
{
ArrayToken destToken = null;
if (found is IndirectReferenceToken indirect)
{
var pageObject = structure.GetObject(indirect.Data);
if (pageObject.Data is DictionaryToken dictionaryToken)
{
if (!dictionaryToken.TryGet(NameToken.D, out destToken))
{
throw new ArgumentException("BookmarksProvider.GetNamedDestination(): Cannot find token 'D'.");
}
}
else if (pageObject.Data is ArrayToken arrayToken)
{
destToken = arrayToken;
}
else
{
throw new NotImplementedException("BookmarksProvider.GetNamedDestination(): Token type '" + pageObject.Data + "'.");
}
}
else if (found is ArrayToken arrayToken)
{
destToken = arrayToken;
}
else if (found is DictionaryToken)
{
throw new NotImplementedException("BookmarksProvider.GetNamedDestination(): Token type 'DictionaryToken'.");
}
else
{
throw new NotImplementedException("BookmarksProvider.GetNamedDestination(): Token type '" + found.GetType() + "'.");
}
var pageNumber = structure.Catalog.GetPageByReference(((IndirectReferenceToken)destToken[0]).Data).PageNumber;
if (pageNumber.HasValue)
{
currentNode.PageNumber = pageNumber.Value;
}
GetDestination(destToken, currentNode);
}
}
}
}
private IToken FindInNameTree<T>(T find, DictionaryToken dictionaryToken) where T : IDataToken<string>
{
// 7.9.6 Name Trees
// Intermediate node
if (dictionaryToken.TryGet(NameToken.Kids, out ArrayToken kidsToken))
{
foreach (var kid in kidsToken.Data)
{
var dictionary = structure.GetObject(((IndirectReferenceToken)kid).Data).Data as DictionaryToken;
if (dictionary != null && dictionary.TryGet(NameToken.Limits, out ArrayToken limits))
{
// (Intermediate and leaf nodes only; required) Shall be an array of two strings,
// that shall specify the (lexically) least and greatest keys included in the
// Names array of a leaf node or in the Names arrays of any leaf nodes that are
// descendants of an intermediate node.
var least = limits[0] as IDataToken<string>;
var greatest = limits[1] as IDataToken<string>;
if (IsStringBetween(find.Data, least.Data, greatest.Data))
{
var indRef = FindInNameTree(find, dictionary);
if (indRef != null)
{
return indRef;
}
else
{
throw new ArgumentException("BookmarksProvider.FindNamedDestination(): Did no find the key '" + find.Data + "' in Name Tree.");
}
}
}
}
}
else
{
// Leaf node
if (dictionaryToken.TryGet(NameToken.Names, out ArrayToken names))
{
// Names
// Shall be an array of the form [key_1, value_1, key_2, value_2, …, key_n, value_n]
// where each key_i shall be a string and the corresponding value_i shall be the object
// associated with that key. The keys shall be sorted in lexical order, as described below.
for (int i = 0; i < names.Length; i += 2)
{
if (names[i] is IDataToken<string> n && n.Data.Equals(find.Data))
{
return names[i + 1];
}
}
}
else
{
throw new ArgumentNullException("BookmarksProvider.FindNamedDestination(): Could not find ArrayToken 'Names' in dictionary.");
}
}
throw new ArgumentException("BookmarksProvider.FindNamedDestination(): Did no find the key '" + find.Data + "' in Name Tree.");
}
private bool IsStringBetween(string str, string least, string greatest)
{
return (string.Compare(str, least, StringComparison.Ordinal) >= 0 &&
string.Compare(str, greatest, StringComparison.Ordinal) <= 0);
}
#endregion
#region Actions
private void GetActions(IToken actionToken, ref BookmarkNode currentNode)
{
if (actionToken is DictionaryToken dictionaryToken)
{
if (dictionaryToken.TryGet(NameToken.S, out NameToken sToken))
{
if (sToken.Equals(NameToken.GoTo)) // 12.6.4.2, Go-To Actions
{
if (dictionaryToken.TryGet(NameToken.D, out IToken goToToken))
{
HandleGoToAction(goToToken, ref currentNode);
}
else
{
throw new ArgumentException("BookmarksProvider.GetActions(): Could not find token 'D' in 'GoTo'.");
}
}
else if (sToken.Equals(NameToken.GoToR)) // 12.6.4.3, Remote Go-To Actions
{
if (dictionaryToken.TryGet(NameToken.D, out IToken goToRToken))
{
if (dictionaryToken.TryGet(NameToken.F, out IToken remoteFileToken))
{
currentNode.ExternalLink = GetString(NameToken.F, remoteFileToken);
}
HandleGoToRAction(goToRToken, ref currentNode);
}
else
{
throw new ArgumentException("BookmarksProvider.GetActions(): Could not find token 'D' in 'GoToR'.");
}
}
else
{
currentNode.IsExternal = true;
log.Debug("BookmarksProvider.GetActions(): Ignoring unknown token '" + sToken.Data + "'.");
}
}
else
{
throw new ArgumentException("BookmarksProvider.GetActions(): Could not find token 'S' in 'Action'.");
}
}
else if (actionToken is IndirectReferenceToken indirectReferenceToken)
{
var tempToken = structure.GetObject(indirectReferenceToken.Data).Data;
if (tempToken is DictionaryToken dictionaryAction)
{
GetActions(dictionaryAction, ref currentNode);
}
else
{
throw new NotImplementedException("BookmarksProvider.GetActions(): " + nameof(tempToken) + " of type " + tempToken.GetType() + ".");
}
}
else
{
throw new NotImplementedException("BookmarksProvider.GetActions(): " + nameof(actionToken) + " of type " + actionToken.GetType() + ".");
}
}
private void HandleGoToRAction(IToken goToRToken, ref BookmarkNode currentNode)
{
currentNode.IsExternal = true;
HandleGoToAction(goToRToken, ref currentNode);
}
private void HandleGoToAction(IToken goToToken, ref BookmarkNode currentNode)
{
if (goToToken is ArrayToken arrayToken)
{
GetDestination(arrayToken, currentNode);
}
else if (goToToken is IDataToken<string> stringToken)
{
GetNamedDestination(stringToken, ref currentNode);
if (currentNode.PageNumber == 0)
{
currentNode.PageNumber = ParsePageNumber(stringToken.Data);
}
}
else if (goToToken is IndirectReferenceToken indirectReferenceToken)
{
HandleGoToAction(structure.GetObject(indirectReferenceToken.Data).Data, ref currentNode);
}
else
{
throw new NotImplementedException("BookmarksProvider.HandleGoToAction(): " + nameof(goToToken) + " of type " + goToToken.GetType());
}
}
#endregion
}
}

18
src/UglyToad.PdfPig/PdfDocument.cs
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@@ -14,6 +14,7 @@
using Parser;
using Tokenization.Scanner;
using Tokens;
using UglyToad.PdfPig.Outline;
using Util.JetBrains.Annotations;
/// <inheritdoc />
@@ -197,6 +198,23 @@
return true;
}
/// <summary>
/// Gets the bookmarks if this document contains some.
/// </summary>
/// <remarks>This will throw a <see cref="ObjectDisposedException"/> if called on a disposed <see cref="PdfDocument"/>.</remarks>
public bool TryGetBookmarks(out Bookmarks bookmarks)
{
if (isDisposed)
{
throw new ObjectDisposedException("Cannot access the bookmarks after the document is disposed.");
}
var bookmarksProvider = new BookmarksProvider(this.log, this.Structure);
bookmarks = bookmarksProvider.GetBookmarks();
if (bookmarks != null) return true;
return false;
}
/// <summary>
/// Gets the form if this document contains one.
/// </summary>

10
src/UglyToad.PdfPig/Tokens/NameToken.Constants.cs
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@@ -217,6 +217,13 @@
public static readonly NameToken Filter = new NameToken("Filter");
public static readonly NameToken First = new NameToken("First");
public static readonly NameToken FirstChar = new NameToken("FirstChar");
public static readonly NameToken Fit = new NameToken("Fit");
public static readonly NameToken FitB = new NameToken("FitB");
public static readonly NameToken FitBH = new NameToken("FitBH");
public static readonly NameToken FitBV = new NameToken("FitBV");
public static readonly NameToken FitH = new NameToken("FitH");
public static readonly NameToken FitR = new NameToken("FitR");
public static readonly NameToken FitV = new NameToken("FitV");
public static readonly NameToken FitWindow = new NameToken("FitWindow");
public static readonly NameToken Fl = new NameToken("FL");
public static readonly NameToken Flags = new NameToken("Flags");
@@ -244,6 +251,8 @@
// G
public static readonly NameToken G = new NameToken("G");
public static readonly NameToken Gamma = new NameToken("Gamma");
public static readonly NameToken GoTo = new NameToken("GoTo");
public static readonly NameToken GoToR = new NameToken("GoToR");
public static readonly NameToken Group = new NameToken("Group");
public static readonly NameToken GtsPdfa1 = new NameToken("GTS_PDFA1");
// H
@@ -559,6 +568,7 @@
public static readonly NameToken Xref = new NameToken("XRef");
public static readonly NameToken XrefStm = new NameToken("XRefStm");
public static readonly NameToken XStep = new NameToken("XStep");
public static readonly NameToken XYZ = new NameToken("XYZ");
// Y
public static readonly NameToken YStep = new NameToken("YStep");
public static readonly NameToken Yes = new NameToken("Yes");