pdfreader.cs

pdf阅读器 用于阅读pdf格式的文件 方便 好用 免费的提供

		{
			this.val = truthValue;
		}

		/// <summary>
		/// Returns the string representation of this object.
		/// </summary>
		/// <returns>Either "true" or "false".</returns>
		public override string ToString()
		{
			return val ? "true" : "false";
		}
	}

	/// <summary>
	/// Represents a form field in a PDF document.
	/// Objects of this class should not be created directly, but rather by instantiating any of its subclasses.
	/// </summary>
	[CLSCompliant(true)]
	public class PdfField
	{
		/// <summary>
		/// The object number of this field.
		/// </summary>
		private int objectNumber;
		/// <summary>
		/// The generation number of this field.
		/// </summary>
		private int generationNumber;
		/// <summary>
		/// The field dictionary of this field. See the PDF Reference 8.6.2 Field Dictionaries.
		/// </summary>
		private PdfDictionary fieldDictionary;
		/// <summary>
		/// The serialized form of the object after it was parsed.
		/// </summary>
		private string original;
		/// <summary>
		/// The /AP PDF Name object.
		/// </summary>
		protected static PdfName APName = new PdfName("/AP");
		/// <summary>
		/// The /N PDF Name object.
		/// </summary>
		protected static PdfName NName = new PdfName("/N");
		/// <summary>
		/// The /V PDF Name object.
		/// </summary>
		protected static PdfName VName = new PdfName("/V");
		/// <summary>
		/// The /T PDF Name object.
		/// </summary>
		protected static PdfName TName = new PdfName("/T");
		/// <summary>
		/// The /Ff PDF Name object.
		/// </summary>
		protected static PdfName FFName = new PdfName("/Ff");
		/// <summary>
		/// The /FT PDF Name object.
		/// </summary>
		protected static PdfName FTName = new PdfName("/FT");
		/// <summary>
		/// The /Tx PDF Name object.
		/// </summary>
		protected static PdfName TXName = new PdfName("/Tx");
		/// <summary>
		/// The /Ch PDF Name object.
		/// </summary>
		protected static PdfName CHName = new PdfName("/Ch");
		/// <summary>
		/// The /Btn PDF Name object.
		/// </summary>
		protected static PdfName ButtonName = new PdfName("/Btn");
		/// <summary>
		/// The /Kids PDF Name object.
		/// </summary>
		protected static PdfName KidsName = new PdfName("/Kids");
		/// <summary>
		/// The /AA PDF Name object.
		/// </summary>
		protected static PdfName AAName = new PdfName("/AA");
		/// <summary>
		/// The /TM PDF Name object.
		/// </summary>
		protected static PdfName TMName = new PdfName("/TM");
		/// <summary>
		/// The /TU PDF Name object.
		/// </summary>
		protected static PdfName TUName = new PdfName("/TU");
		/// <summary>
		/// The /Parent PDF Name object.
		/// </summary>
		protected static PdfName ParentName = new PdfName("/Parent");

		/// <summary>
		/// The object number of this field.
		/// </summary>
		public int ObjectNumber
		{
			get
			{
				return objectNumber;
			}

			set
			{
				objectNumber = value;
			}
		}

		/// <summary>
		/// The generation number of this field.
		/// </summary>
		public int GenerationNumber
		{
			get
			{
				return generationNumber;
			}

			set
			{
				generationNumber = value;
			}
		}

		/// <summary>
		/// The field dictionary of this field. See the PDF Reference 8.6.2 Field Dictionaries.
		/// </summary>
		public PdfDictionary FieldDictionary
		{
			get
			{
				return fieldDictionary;
			}

			set
			{
				fieldDictionary = value;
			}
		}

		/// <summary>
		/// Initializes a new instance of PdfField with the specified object number, generation number,
		/// and field dictionary.
		/// </summary>
		/// <param name="objNumber">The object number.</param>
		/// <param name="generationNumber">The generation number.</param>
		/// <param name="fieldDictionary">The field dictionary.</param>
		protected PdfField(int objNumber, int generationNumber, PdfDictionary fieldDictionary)
		{
			ObjectNumber = objNumber;
			GenerationNumber = generationNumber;
			FieldDictionary = fieldDictionary;
			original = GetString();
		}
		
		/// <summary>
		/// Factory method for PdfField objects. 
		/// Initializes new objects according to the contents of the specified field dictionary.
		/// Does not currently support signature fields.
		/// In most cases, this will return just one object. However, fields are organized according
		/// to trees, where intermediate field objects may have child fields. Only terminal field objects
		/// are "real" fields, so this method may return more than one field.
		/// </summary>
		/// <param name="reference">The reference to the root node of the fields.</param>
		/// <param name="reader">The PdfReader object from which to fetch additional child objects.</param>
		/// <param name="parentDictionary">The accumulated field dictionary of the ancestor objects.
		/// May be null for the root object.</param>
		/// <param name="fieldName">The complete field name up to this object, e.g. "a.b.c".</param>
		/// <returns>A new PdfField object.</returns>
		/// <exception cref="Exception">Thrown when the field dictionary does not contain
		/// a known field type.</exception>
		public static PdfField[] GetPdfFields(PdfReference reference, PdfReader reader, 
			PdfDictionary parentDictionary, string fieldName)
		{
			int objNumber = reference.ObjectNumber;
			int generationNumber = reference.GenerationNumber;
			PdfDictionary fieldDictionary = (PdfDictionary)reader.GetObjectForReference(reference);

			// get the path name
			if (fieldDictionary["/T"] != null)
			{
				if (fieldName != "")
				{
					fieldName += ".";
				}

				fieldName += ((PdfString)fieldDictionary["/T"]).Text;
			}

			if (parentDictionary != null)
			{
				// add all ancestral objects that haven't been overwritten by this object
				foreach (object key in parentDictionary.Dictionary.Keys)
				{
					if (!fieldDictionary.Dictionary.ContainsKey(key))
					{
						fieldDictionary.Dictionary.Add(key, parentDictionary.Dictionary[key]);
					}
				}
			}

			if (fieldDictionary["/Kids"] == null || PdfButtonField.IsRadioButton(fieldDictionary))
			{
				// it's a terminal node

				PdfName fieldType = (PdfName)fieldDictionary.GetElement(FTName);
				PdfField field;

				if (fieldType.Equals(TXName))
				{
					field = new PdfTXField(objNumber, generationNumber, fieldDictionary);
				}
				else if (fieldType.Equals(CHName))
				{
					field = new PdfCHField(objNumber, generationNumber, fieldDictionary);
				}
				else if (fieldType.Equals(ButtonName))
				{
					field = PdfButtonField.GetButtonField(objNumber, generationNumber, fieldDictionary);		
				}
				else
				{
					throw new Exception("unsupported field type '" + fieldType.ToString() + "'");
				}

				field.FieldName = fieldName;

				return new PdfField[] { field };
			}
			else
			{
				// it's an intermediate node

				ArrayList fields = new ArrayList();
				PdfArray kids = (PdfArray)fieldDictionary.GetElement(KidsName);

				foreach (PdfReference child in kids.Elements)
				{
					PdfDictionary childDictionary = new PdfDictionary(new Hashtable(fieldDictionary.Dictionary));
					// these are not inheritable
					childDictionary.Dictionary.Remove(KidsName);
					childDictionary.Dictionary.Remove(TName);
					childDictionary.Dictionary.Remove(AAName);
					childDictionary.Dictionary.Remove(TMName);
					childDictionary.Dictionary.Remove(TUName);
					childDictionary.Dictionary.Remove(ParentName);
					fields.AddRange(GetPdfFields(child, reader, childDictionary, fieldName));		
				}

				return (PdfField[])fields.ToArray(typeof(PdfField));
			}
		}

		/// <summary>
		/// Returns true if changes were made to the field after it was created.
		/// </summary>
		/// <returns>true if there are changes.</returns>
		public bool HasChanged()
		{
			bool hasChanged = !original.Equals(ToString());
			return hasChanged;
		}

		/// <summary>
		/// Returns the string representation of this form field.
		/// </summary>
		/// <returns>The string representation of this form field.</returns>
		public override string ToString()
		{
			return GetString();
		}

		private string GetString()
		{
			string s = ObjectNumber.ToString(CultureInfo.InvariantCulture) + " " + GenerationNumber + " obj\n";
			s += FieldDictionary.ToString();
			s += "\nendobj\n";

			return s;
		}

		/// <summary>
		/// Gets or sets the name of this field. This is not the complete field name, just the local part,
		/// e.g. "c" where the complete field name is "a.b.c".
		/// </summary>
		/// <value>The name of this form field.</value>
		public string Name
		{
			get
			{
				if (FieldDictionary.Dictionary.ContainsKey(TName) && FieldDictionary.Dictionary[TName].GetType() == typeof (PdfString))
				{
					PdfString name = (PdfString)FieldDictionary.Dictionary[TName];
					return name.Text;
				}
				else
				{
					return "";
				}
			}

			set
			{
				string s = "()";
				PdfString name = new PdfString(false, ref s);
				name.Text = value;
				FieldDictionary.SetElement(TName, name);
			}
		}

		/// <summary>
		/// The complete field name.
		/// </summary>
		private string completeFieldName;

		/// <summary>
		/// Gets or Sets the complete field name.
		/// </summary>
		public string FieldName
		{
			get
			{
				return completeFieldName;
			}

			set
			{
				this.completeFieldName = value;
			}
		}

		/// <summary>
		/// Returns the bit at the specified position in the field flags of this field.
		/// </summary>
		/// <param name="bitPosition">The bit position starting at 1.</param>
		/// <returns>true if the bit's value is 1.</returns>
		public bool GetBit(int bitPosition)
		{
			bool bit = false;
			if (FieldDictionary.Dictionary.ContainsKey(FFName) && FieldDictionary.Dictionary[FFName].GetType() == typeof (PdfNumber))
			{
				PdfNumber number = (PdfNumber)FieldDictionary.Dictionary[FFName];
				bit = ((int)number.Number & (1 << (bitPosition - 1))) > 0;
			}

			return bit;
		}

		/// <summary>
		/// Sets the bit at the specified position in the field flags of this field.
		/// </summary>
		/// <param name="bitPosition">The bit position starting at 1.</param>
		/// <param name="bit">true to set the bit's value to 1.</param>
		public void SetBit(int bitPosition, bool bit)
		{
			int num = 0;
			if (FieldDictionary.Dictionary.ContainsKey(FFName) && FieldDictionary.Dictionary[FFName].GetType() == typeof (PdfNumber))
			{
				num = (int)((PdfNumber)FieldDictionary.Dictionary[FFName]).Number;
			}

			if (bit)
			{
				num = (int)num | (1 << (bitPosition - 1));
			}
			else
			{
				num = (int)num & ~(1 << (bitPosition - 1));
			}

			FieldDictionary.SetElement(FFName, new PdfNumber(num.ToString(CultureInfo.InvariantCulture)));
		}
	}

	/// <summary>
	/// Represents a generic Button form field in a PDF document.
	/// Instances of this class should not be created through the constructor but instead through the factory
	/// method <see cref="GetButtonField"/>.
	/// See the PDF reference 8.6.3 Field Types.
	/// </summary>
	[CLSCompliant(true)]
	public class PdfButtonField: PdfField
	{
		private static readonly Regex btnRegex = new Regex(@"/Ff\s+(\d+)", RegexOptions.Singleline);

		/// <summary>
		/// Initializes a new instance of PdfButtonField with the specified object number, generation number,
		/// and field dictionary.
		/// </summary>
		/// <param name="objNumber">The object number.</param>
		/// <param name="generationNumber">The generation number.</param>
		/// <param name="fieldDictionary">The field dictionary.</param>
		protected PdfButtonField(int objNumber, int generationNumber, PdfDictionary fieldDictionary): base(objNumber,
			generationNumber, fieldDictionary)
		{
		}

		/// <summary>
		/// Creates either a <see cref="PdfPushButtonField"/>, <see cref="PdfRadioButtonField"/>, or a
		/// <see cref="PdfCheckBoxField"/> according to the parsed field dictionary.
		/// </summary>
		/// <param name="objNumber">The object number.</param>
		/// <param name="generationNumber">The generation number.</param>
		/// <param name="fieldDictionary">The field dictionary.</param>
		/// <returns></returns>
		public static PdfButtonField GetButtonField(int objNumber, int generationNumber, PdfDictionary fieldDictionary)
		{
			int flags = 0;

			PdfNumber num = (PdfNumber)fieldDictionary.GetElement(FFName);
			if (num != null)
			{
				flags = (int)num.Number;
			}

			if ((flags & (1 << 16)) > 0)
			{
				return new PdfPushButtonField(objNumber, generationNumber, fieldDictionary);
			}
			else if ((flags & (1 << 15)) > 0)
			{
				return new PdfRadioButtonField(objNumber, generationNumber, fieldDictionary);
			}
			else
			{
				return new PdfCheckBoxField(objNumber, generationNumber, fieldDictionary);
			}
		}

		/// <summary>
		/// Determines whether the object specified is a RadioButton.
		/// </summary>
		/// <param name="fieldDictionary">The object's field dictionary.</param>
		/// <returns>true if the object specified is a RadioButton, false otherwise.</returns>
		public static bool IsRadioButton(PdfDictionary fieldDictionary)
		{
			if (!IsButton(fieldDictionary))
			{
				return false;
			}

			PdfNumber num = fieldDictionary.GetElement(FFName) as PdfNumber;
			if (num != null)
			{
				int flags = (int)num.Number;
				return ((flags & (1 << 15)) > 0);
			}
			else
			{
				return false;
			}
		}

		/// <summary>
		/// Determines whether the object specified is a Button.
		/// </summary>
		/// <param name="fieldDictionary">The object's field dictionary.</param>
		/// <returns>true if the object specified is a Button, false otherwise.</returns>
		protected static bool IsButton(PdfDictionary fieldDictionary)