Chapter 18 - Under the Hood

This web page contains the converted source code from Chapter 18 (Under the Hood) of Bruno Lowagie's book iText in Action.
///// SilentPrinting /////

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace SilentPrinting
{
    class Program
    {
        static void Main(string[] args)
        {
            // Generates a file that will print immediately.
	        // 
	        // @param args:  no arguments needed here

            Console.WriteLine("Chapter 18: example Silent Printing");
		    Console.WriteLine("-> Creates a PDF file that prints after opening.");
		    Console.WriteLine("-> files generated in /results subdirectory:");
		    Console.WriteLine("   silent_printing.pdf");
		    // step 1: creation of a document-object
		    Document document = new Document();
		    try 
            { 
			    // step 2:
			    PdfWriter writer = PdfWriter.GetInstance(document, new FileStream("silent_printing.pdf", FileMode.Create));
			    // step 3:
			    document.Open();
			    // step 4: we grab the ContentByte and do some stuff with it
			    writer.AddJavaScript("this.print(false);", false);
			    document.Add(new Paragraph("Testing Silent Printing with iText"));
		    } 
            
            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

		    document.Close();

            Console.ReadLine();
        }
    }
}

///// HelloWorldStreamHack /////

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace HelloWorldStreamHack
{
    class Program
    {
        static void Main(string[] args)
        {
            // Generates a PDF file with the text 'Hello World' and then reads it to
	        // look what it's like internally.
	        // 
	        // @param args:  no arguments needed here

            Console.WriteLine("Chapter 18: example HelloWorldStream");
		    Console.WriteLine("-> Creates a PDF file and then inspects the content stream.");
		    Console.WriteLine("-> files generated:");
		    Console.WriteLine("   HelloWorldStream.pdf and HelloWorldStreamHack.pdf");
 
		    // we create a PDF file
		    createPdf("HelloWorldStream.pdf");
 
		    // now we are going to read the file and extract the content stream
		    try 
            {
			    // creating a reader object that will read the file we created
			    // earlier
			    PdfReader reader = new PdfReader("HelloWorldStream.pdf");
			    // we can inspect the syntax of the imported page
			    byte[] streamBytes = reader.GetPageContent(1);
			    String contentStream = ASCIIEncoding.ASCII.GetString(streamBytes, 0, streamBytes.Length);
			    Console.WriteLine(contentStream);
			    // we do some dirty hacking, replacing Hello World by something else
			    StringBuilder buf = new StringBuilder();
			    int pos = contentStream.IndexOf("Hello World") + 11;
			    buf.Append(contentStream.Substring(0, pos));
			    buf.Append(", Hello Sun, Hello Moon, Hello Stars, Hello Universe");
			    buf.Append(contentStream.Substring(pos));
			    String hackedContentStream = buf.ToString();
			    // we create a new PDF file that contains the hacked stream
			    PdfStamper stamper = new PdfStamper(reader, new FileStream("HelloWorldStreamHack.pdf", FileMode.Create));
			    reader.SetPageContent(1, ASCIIEncoding.ASCII.GetBytes(hackedContentStream));
			    stamper.Close();
		    } 
            
            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

            Console.ReadLine();
        }

        private static void createPdf(String filename)
        {
            Document document = new Document(PageSize.A6);
            try
            {
                PdfWriter.GetInstance(document, new FileStream(filename, FileMode.Create));
                document.Open();
                document.Add(new Paragraph("Hello World"));
                document.Add(new Paragraph("Hello People"));
            }

            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

            document.Close();
        }
    }
}

///// HelloWorldStream /////

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace HelloWorldStream
{
    class Program
    {
        static void Main(string[] args)
        {
            // Generates a PDF file with the text 'Hello World' and then reads it to
	        // look what it's like internally.
	        // 
	        // @param args:  no arguments needed here

            Console.WriteLine("Chapter 18: example HelloWorldStream");
		    Console.WriteLine("-> Creates a PDF file and then inspects the content stream.");
		    Console.WriteLine("-> files generated:");
		    Console.WriteLine("   HelloWorldStream.pdf and HelloWorldStreamHacked.pdf");
 
		    // we create a PDF file
		    createPdf("HelloWorldStream.pdf");
 
		    // now we are going to read the file and extract the content stream
		    try 
            {
			    // creating a reader object that will read the file we created earlier
			    PdfReader reader = new PdfReader("HelloWorldStream.pdf");
			    // we can inspect the syntax of the imported page
			    PdfDictionary page = reader.GetPageN(1);
			    PRIndirectReference objectReference = (PRIndirectReference) page.Get(PdfName.CONTENTS);
			    Console.WriteLine("=== inspecting the stream of page 1 in object " + objectReference.Number + " ===");
			    PRStream stream = (PRStream) PdfReader.GetPdfObject(objectReference);
			    byte[] streamBytes = PdfReader.GetStreamBytes(stream);
			    String contentStream = ASCIIEncoding.ASCII.GetString(streamBytes, 0, streamBytes.Length);
			    Console.WriteLine(contentStream);
			    // we can retrieve the String sections of the content stream
                Console.WriteLine("=== extracting the strings from the stream ===");
			    PRTokeniser tokenizer = new PRTokeniser(streamBytes);
			    
                while (tokenizer.NextToken()) 
                {
				    if (tokenizer.TokenType == PRTokeniser.TK_STRING) 
                    {
					    Console.WriteLine(tokenizer.StringValue);
				    }
			    }

			    // we do some dirty hacking, replacing Hello World by something else
			    StringBuilder buf = new StringBuilder();
			    int pos = contentStream.IndexOf("Hello World") + 11;
			    buf.Append(contentStream.Substring(0, pos));
			    buf.Append(", Hello Sun, Hello Moon, Hello Stars, Hello Universe");
			    buf.Append(contentStream.Substring(pos));
			    String hackedContentStream = buf.ToString();
			    // we create a new PDF file that contains the hacked stream
			    Document document = new Document(PageSize.A6);
			    PdfWriter writer = PdfWriter.GetInstance(document, new FileStream("HelloWorldStreamHacked.pdf", FileMode.Create));
			    document.Open();
			    PdfContentByte cb = writer.DirectContent;
			    cb.SetLiteral(hackedContentStream);
			    document.Close();
		    } 
            
            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

            Console.ReadLine();
        }

        private static void createPdf(String filename)
        {
            Document document = new Document(PageSize.A6);
            try
            {
                PdfWriter.GetInstance(document, new FileStream(filename, FileMode.Create));
                document.Open();
                document.Add(new Paragraph("Hello World"));
                document.Add(new Paragraph("Hello People"));
            }

            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

            document.Close();
        }
    }
}

///// HelloWorldReverse /////

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace HelloWorldReverse
{
    class Program
    {
        static void Main(string[] args)
        {
            // Generates a PDF file with the text 'Hello World'
	        // @param args:  no arguments needed here

            Console.WriteLine("Chapter 18: example HelloWorldReverse");
		    Console.WriteLine("-> Creates a PDF file with the text 'Hello World';");
		    Console.WriteLine("   the text is added at absolute positions in reverse order;");
		    Console.WriteLine("   the stream is inspected afterwards.");
		    Console.WriteLine("-> files generated:");
		    Console.WriteLine("   HelloWorldReverse.pdf");
		    Document document = new Document(PageSize.A6);
		    try 
            {
			    PdfWriter writer = PdfWriter.GetInstance(document, new FileStream("HelloWorldReverse.pdf", FileMode.Create));
			    document.Open();
			    // we add the text to the direct content, but not in the right order
			    PdfContentByte cb = writer.DirectContent;
			    BaseFont bf = BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.CP1252, BaseFont.NOT_EMBEDDED);
                cb.BeginText();
                cb.SetFontAndSize(bf, 12);
                cb.MoveText(88.66f, 367); 
                cb.ShowText("ld");
                cb.MoveText(-22f, 0); 
                cb.ShowText("Wor");
                cb.MoveText(-15.33f, 0); 
                cb.ShowText("llo");
                cb.MoveText(-15.33f, 0); 
                cb.ShowText("He");
                cb.EndText();
                PdfTemplate tmp = cb.CreateTemplate(250, 25);
                tmp.BeginText();
                tmp.SetFontAndSize(bf, 12);
                tmp.MoveText(0, 7);
                tmp.ShowText("Hello People");
                tmp.EndText();
                cb.AddTemplate(tmp, 36, 343);
		    } 
            
            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

		    document.Close();
 
		    // now we are going to read the file and extract the content stream
		    try 
            {
			    // creating a reader object that will read the file we created earlier
			    PdfReader reader = new PdfReader("HelloWorldReverse.pdf");
			    // we can inspect the syntax of the imported page
			    PdfDictionary page = reader.GetPageN(1);
			    PRIndirectReference objectReference = (PRIndirectReference) page.Get(PdfName.CONTENTS);
			    Console.WriteLine("=== inspecting the stream of page 1 in object " + objectReference.Number + " ===");
			    PRStream stream = (PRStream) PdfReader.GetPdfObject(objectReference);
			    byte[] streamBytes = PdfReader.GetStreamBytes(stream);
			    Console.WriteLine(ASCIIEncoding.ASCII.GetString(streamBytes, 0, streamBytes.Length));
			    Console.WriteLine("=== extracting the strings from the stream ===");
			    PRTokeniser tokenizer = new PRTokeniser(streamBytes);
			    while (tokenizer.NextToken()) 
                {
				    if (tokenizer.TokenType == PRTokeniser.TK_STRING) 
                    {
					    Console.WriteLine(tokenizer.StringValue);
				    }
			    }
		    } 
            
            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

            Console.ReadLine();
        }
    }
}

///// HelloWorld /////

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace HelloWorld
{
    class Program
    {
        static void Main(string[] args)
        {
            // Generates a PDF file with the text 'Hello World'
	        // 
	        // @param args:  no arguments needed here

            Console.WriteLine("Chapter 18: example HelloWorld");
		    Console.WriteLine("-> Creates a PDF file with the text 'Hello World';");
		    Console.WriteLine("   Default values are used for PageSize and margins.");
		    Console.WriteLine("-> files generated:");
		    Console.WriteLine("   HelloWorld.pdf and updated.pdf");
		    // step 1: creation of a document-object
		    Document.Compress = false;
		    Document document = new Document();
		    try 
            {
			    // step 2:
			    // we create a writer
			    PdfWriter.GetInstance(
			            // that listens to the document
					    document,
					    // and directs a PDF-stream to a file
					    new FileStream("HelloWorld.pdf", FileMode.Create));
			    // step 3: we open the document
			    document.Open();
			    // step 4: we add a paragraph to the document
			    document.Add(new Paragraph("Hello World"));
		    } 
            
            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }
 
		    // step 5: we close the document
		    document.Close();
 
		    try 
            {
			    PdfReader reader = new PdfReader("HelloWorld.pdf");
			    PdfStamper stamper = new PdfStamper(reader, new FileStream("updated.pdf", FileMode.Create), '\0', true);
			    PdfContentByte cb = stamper.GetOverContent(1);
			    cb.BeginText();
			    cb.SetFontAndSize(BaseFont.CreateFont(BaseFont.HELVETICA, BaseFont.WINANSI, BaseFont.EMBEDDED), 12);
			    cb.ShowTextAligned(Element.ALIGN_LEFT, "Hello People", 36, 770, 0);
			    cb.EndText();
			    stamper.Close();
		    }

            catch (DocumentException de)
            {
                Console.Error.WriteLine(de.Message);
            }

            catch (IOException ioe)
            {
                Console.Error.WriteLine(ioe.Message);
            }

            Console.ReadLine();
        }
    }
}

///// This page is still under construction /////
Code Hacker Software Development

Chapter 18 - Under the Hood
