src/org/pdfbox/Overlay.java - pdfbox - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.pdfbox;

 import org.pdfbox.cos.COSArray;
 import org.pdfbox.cos.COSBase;
 import org.pdfbox.cos.COSDictionary;
 import org.pdfbox.cos.COSName;
 import org.pdfbox.cos.COSStream;
 import org.pdfbox.cos.COSInteger;
 import org.pdfbox.exceptions.COSVisitorException;
 import org.pdfbox.pdfparser.PDFParser;
 import org.pdfbox.pdfwriter.COSWriter;

 import org.pdfbox.pdmodel.PDDocument;
 import org.pdfbox.pdmodel.PDDocumentCatalog;
 import org.pdfbox.pdmodel.PDPage;
 import org.pdfbox.pdmodel.PDResources;

 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.OutputStream;

 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.TreeMap;
 import java.util.Map;

 /**
  * Overlay on document with another one.<br>
  * e.g. Overlay an invoice with your company layout<br>
  * <br>
  * How it (should) work:<br>
  * If the document has 10 pages, and the layout 2 the following is the result:<br>
  * <pre>
  * Document: 1234567890
  * Layout  : 1212121212
  * </pre>
  * <br>
  *
  * @author Mario Ivankovits (mario@ops.co.at)
  * @author <a href="ben@benlitchfield.com">Ben Litchfield</a>
  *
  * @version $Revision: 1.7 $
  */
 public class Overlay
 {
     /**
      * COSName constant.
      */
     public static final COSName XOBJECT = COSName.getPDFName("XObject");
     /**
      * COSName constant.
      */
     public static final COSName PROC_SET = COSName.getPDFName("ProcSet");
     /**
      * COSName constant.
      */
     public static final COSName EXT_G_STATE = COSName.getPDFName("ExtGState" );

     private List layoutPages = new ArrayList(10);

     private PDDocument pdfOverlay;
     private PDDocument pdfDocument;
     private int pageCount = 0;
     private COSStream saveGraphicsStateStream;
     private COSStream restoreGraphicsStateStream;

     /**
      * This will overlay a document and write out the results.<br/><br/>
      *
      * usage: java org.pdfbox.Overlay &lt;overlay.pdf&gt; &lt;document.pdf&gt; &lt;result.pdf&gt;
      *
      * @param args The command line arguments.
      *
      * @throws IOException If there is an error reading/writing the document.
      * @throws COSVisitorException If there is an error writing the document.
      */
     public static void main( String[] args ) throws IOException, COSVisitorException
     {
         if( args.length != 3 )
         {
             usage();
             System.exit(1);
         }
         else
         {
             PDDocument overlay = null;
             PDDocument pdf = null;

             try
             {
                 overlay = getDocument( args[0] );
                 pdf = getDocument( args[1] );
                 Overlay overlayer = new Overlay();
                 overlayer.overlay( overlay, pdf );
                 writeDocument( pdf, args[2] );
             }
             finally
             {
                 if( overlay != null )
                 {
                     overlay.close();
                 }
                 if( pdf != null )
                 {
                     pdf.close();
                 }
             }
         }
     }

     private static void writeDocument( PDDocument pdf, String filename ) throws IOException, COSVisitorException
     {
         FileOutputStream output = null;
         COSWriter writer = null;
         try
         {
             output = new FileOutputStream( filename );
             writer = new COSWriter( output );
             writer.write( pdf );
         }
         finally
         {
             if( writer != null )
             {
                 writer.close();
             }
             if( output != null )
             {
                 output.close();
             }
         }
     }

     private static PDDocument getDocument( String filename ) throws IOException
     {
         FileInputStream input = null;
         PDFParser parser = null;
         PDDocument result = null;
         try
         {
             input = new FileInputStream( filename );
             parser = new PDFParser( input );
             parser.parse();
             result = parser.getPDDocument();
         }
         finally
         {
             if( input != null )
             {
                 input.close();
             }
         }
         return result;
     }

     private static void usage()
     {
         System.err.println( "usage: java " + Overlay.class.getName() + " <overlay.pdf> <document.pdf> <result.pdf>" );
     }

     /**
      * Private class.
      */
     private static class LayoutPage
     {
         private final COSBase contents;
         private final COSDictionary res;
         private final Map objectNameMap;

         /**
          * Constructor.
          *
          * @param contentsValue The contents.
          * @param resValue The resource dictionary
          * @param objectNameMapValue The map
          */
         public LayoutPage(COSBase contentsValue, COSDictionary resValue, Map objectNameMapValue)
         {
             contents = contentsValue;
             res = resValue;
             objectNameMap = objectNameMapValue;
         }
     }

     /**
      * This will overlay two documents onto each other.  The overlay document is
      * repeatedly overlayed onto the destination document for every page in the
      * destination.
      *
      * @param overlay The document to copy onto the destination
      * @param destination The file that the overlay should be placed on.
      *
      * @return The destination pdf, same as argument passed in.
      *
      * @throws IOException If there is an error accessing data.
      */
     public PDDocument overlay( PDDocument overlay, PDDocument destination ) throws IOException
     {
         pdfOverlay = overlay;
         pdfDocument = destination;

         PDDocumentCatalog overlayCatalog = pdfOverlay.getDocumentCatalog();
         collectLayoutPages( overlayCatalog.getAllPages() );

         COSDictionary saveGraphicsStateDic = new COSDictionary();
         saveGraphicsStateStream = new COSStream( saveGraphicsStateDic, pdfDocument.getDocument().getScratchFile() );
         OutputStream saveStream = saveGraphicsStateStream.createUnfilteredStream();
         saveStream.write( " q\n".getBytes() );
         saveStream.flush();

         restoreGraphicsStateStream = new COSStream( saveGraphicsStateDic, pdfDocument.getDocument().getScratchFile() );
         OutputStream restoreStream = restoreGraphicsStateStream.createUnfilteredStream();
         restoreStream.write( " Q\n".getBytes() );
         restoreStream.flush();


         PDDocumentCatalog pdfCatalog = pdfDocument.getDocumentCatalog();
         processPages( pdfCatalog.getAllPages() );

         return pdfDocument;
     }

     private void collectLayoutPages( List pages) throws IOException
     {
         Iterator pagesIter = pages.iterator();
         while( pagesIter.hasNext() )
         {
             PDPage page = (PDPage)pagesIter.next();
             COSBase contents = page.getCOSDictionary().getDictionaryObject( COSName.CONTENTS );
             PDResources resources = page.findResources();
             if( resources == null )
             {
                 resources = new PDResources();
                 page.setResources( resources );
             }
             COSDictionary res = resources.getCOSDictionary();

             if( contents instanceof COSStream )
             {
                 COSStream stream = (COSStream) contents;
                 Map objectNameMap = new TreeMap();
                 stream = makeUniqObjectNames(objectNameMap, stream);

                 layoutPages.add(new LayoutPage(stream, res, objectNameMap));
             }
             else if( contents instanceof COSArray )
             {
                 throw new UnsupportedOperationException("Layout pages with COSArray currently not supported.");
                 // layoutPages.add(new LayoutPage(contents, res));
             }
             else
             {
                 throw new IOException( "Contents are unknown type:" + contents.getClass().getName() );
             }
         }
     }

     private COSStream makeUniqObjectNames(Map objectNameMap, COSStream stream) throws IOException
     {
         ByteArrayOutputStream baos = new ByteArrayOutputStream(10240);

         byte[] buf = new byte[10240];
         int read;
         InputStream is = stream.getUnfilteredStream();
         while ((read = is.read(buf)) > -1)
         {
             baos.write(buf, 0, read);
         }

         buf = baos.toByteArray();
         baos = new ByteArrayOutputStream(buf.length + 100);
         StringBuffer sbObjectName = new StringBuffer(10);
         boolean bInObjectIdent = false;
         boolean bInText = false;
         boolean bInEscape = false;
         for (int i = 0; i<buf.length; i++)
         {
             byte b = buf[i];

             if (!bInEscape)
             {
                 if (!bInText && b == '(')
                 {
                     bInText = true;
                 }
                 if (bInText && b == ')')
                 {
                     bInText = false;
                 }
                 if (b == '\\')
                 {
                     bInEscape = true;
                 }

                 if (!bInText && !bInEscape)
                 {
                     if (b == '/')
                     {
                         bInObjectIdent = true;
                     }
                     else if (bInObjectIdent && Character.isWhitespace((char) b))
                     {
                         bInObjectIdent = false;

                         // System.err.println(sbObjectName);
                         // String object = sbObjectName.toString();

                         String objectName = sbObjectName.toString().substring(1);
                         String newObjectName = objectName + "overlay";
                         baos.write('/');
                         baos.write(newObjectName.getBytes());

                         objectNameMap.put(objectName, COSName.getPDFName(newObjectName));

                         sbObjectName.delete(0, sbObjectName.length());
                     }
                 }

                 if (bInObjectIdent)
                 {
                     sbObjectName.append((char) b);
                     continue;
                 }
             }
             else
             {
                 bInEscape = false;
             }

             baos.write(b);
         }

         COSDictionary streamDict = new COSDictionary();
         streamDict.setItem(COSName.LENGTH, new COSInteger(baos.size()));
         COSStream output = new COSStream(streamDict, pdfDocument.getDocument().getScratchFile());
         output.setFilters(stream.getFilters());
         OutputStream os = output.createUnfilteredStream();
         baos.writeTo(os);
         os.close();

         return output;
     }

     private void processPages( List pages ) throws IOException
     {
         Iterator pageIter = pages.iterator();
         while( pageIter.hasNext() )
         {
             PDPage page = (PDPage)pageIter.next();
             COSDictionary pageDictionary = page.getCOSDictionary();
             COSBase contents = pageDictionary.getDictionaryObject( COSName.CONTENTS );
             if( contents instanceof COSStream )
             {
                 COSStream contentsStream = (COSStream)contents;
                 // System.err.println("stream");

                 COSArray array = new COSArray();

                 array.add(contentsStream);

                 mergePage( array, page );

                 pageDictionary.setItem(COSName.CONTENTS, array);
             }
             else if( contents instanceof COSArray )
             {
                 COSArray contentsArray = (COSArray)contents;

                 mergePage( contentsArray, page );
             }
             else
             {
                 throw new IOException( "Contents are unknown type:" + contents.getClass().getName() );
             }
             pageCount++;
         }
     }

     private void mergePage(COSArray array, PDPage page )
     {
         int layoutPageNum = pageCount % layoutPages.size();
         LayoutPage layoutPage = (LayoutPage) layoutPages.get(layoutPageNum);
         PDResources resources = page.findResources();
         if( resources == null )
         {
             resources = new PDResources();
             page.setResources( resources );
         }
         COSDictionary docResDict = resources.getCOSDictionary();
         COSDictionary layoutResDict = layoutPage.res;
         mergeArray(PROC_SET, docResDict, layoutResDict);
         mergeDictionary(COSName.FONT, docResDict, layoutResDict, layoutPage.objectNameMap);
         mergeDictionary(XOBJECT, docResDict, layoutResDict, layoutPage.objectNameMap);
         mergeDictionary(EXT_G_STATE, docResDict, layoutResDict, layoutPage.objectNameMap);

         //we are going to wrap the existing content around some save/restore
         //graphics state, so the result is
         //
         //<save graphics state>
         //<all existing content streams>
         //<restore graphics state>
         //<overlay content>
         array.add(0, saveGraphicsStateStream );
         array.add( restoreGraphicsStateStream );
         array.add(layoutPage.contents);
     }

     /**
      * merges two dictionaries.
      *
      * @param dest
      * @param source
      */
     private void mergeDictionary(COSName name, COSDictionary dest, COSDictionary source, Map objectNameMap)
     {
         COSDictionary destDict = (COSDictionary) dest.getDictionaryObject(name);
         COSDictionary sourceDict = (COSDictionary) source.getDictionaryObject(name);

         if (destDict == null)
         {
             destDict = new COSDictionary();
             dest.setItem(name, destDict);
         }
         if( sourceDict != null )
         {

             Iterator iterKeys = sourceDict.keyList().iterator();
             while (iterKeys.hasNext())
             {
                 COSName key = (COSName) iterKeys.next();
                 COSName mappedKey = (COSName) objectNameMap.get(key.getName());
                 if (mappedKey == null)
                 {
                     // object not needet
                     continue;
                 }

                 destDict.setItem(mappedKey, sourceDict.getItem(key));
             }
         }
     }

     /**
      * merges two arrays.
      *
      * @param dest
      * @param source
      */
     private void mergeArray(COSName name, COSDictionary dest, COSDictionary source)
     {
         COSArray destDict = (COSArray) dest.getDictionaryObject(name);
         COSArray sourceDict = (COSArray) source.getDictionaryObject(name);

         if (destDict == null)
         {
             destDict = new COSArray();
             dest.setItem(name, destDict);
         }

         for (int sourceDictIdx = 0; sourceDict != null && sourceDictIdx<sourceDict.size(); sourceDictIdx++)
         {
             COSBase key = sourceDict.get(sourceDictIdx);
             if (key instanceof COSName)
             {
                 COSName keyname = (COSName) key;

                 boolean bFound = false;
                 for (int destDictIdx = 0; destDictIdx<destDict.size(); destDictIdx++)
                 {
                     COSBase destkey = destDict.get(destDictIdx);
                     if (destkey instanceof COSName)
                     {
                         COSName destkeyname = (COSName) destkey;
                         if (destkeyname.equals(keyname))
                         {
                             bFound = true;
                             break;
                         }
                     }
                 }
                 if (!bFound)
                 {
                     destDict.add(keyname);
                 }
             }
         }
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.pdfbox;

	import org.pdfbox.cos.COSArray;
	import org.pdfbox.cos.COSBase;
	import org.pdfbox.cos.COSDictionary;
	import org.pdfbox.cos.COSName;
	import org.pdfbox.cos.COSStream;
	import org.pdfbox.cos.COSInteger;
	import org.pdfbox.exceptions.COSVisitorException;
	import org.pdfbox.pdfparser.PDFParser;
	import org.pdfbox.pdfwriter.COSWriter;

	import org.pdfbox.pdmodel.PDDocument;
	import org.pdfbox.pdmodel.PDDocumentCatalog;
	import org.pdfbox.pdmodel.PDPage;
	import org.pdfbox.pdmodel.PDResources;

	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.ByteArrayOutputStream;
	import java.io.OutputStream;

	import java.util.ArrayList;
	import java.util.Iterator;
	import java.util.List;
	import java.util.TreeMap;
	import java.util.Map;

	/**
	* Overlay on document with another one.<br>
	* e.g. Overlay an invoice with your company layout<br>
	* <br>
	* How it (should) work:<br>
	* If the document has 10 pages, and the layout 2 the following is the result:<br>
	* <pre>
	* Document: 1234567890
	* Layout : 1212121212
	* </pre>
	* <br>
	*
	* @author Mario Ivankovits (mario@ops.co.at)
	* @author <a href="ben@benlitchfield.com">Ben Litchfield</a>
	*
	* @version $Revision: 1.7 $
	*/
	public class Overlay
	{
	/**
	* COSName constant.
	*/
	public static final COSName XOBJECT = COSName.getPDFName("XObject");
	/**
	* COSName constant.
	*/
	public static final COSName PROC_SET = COSName.getPDFName("ProcSet");
	/**
	* COSName constant.
	*/
	public static final COSName EXT_G_STATE = COSName.getPDFName("ExtGState" );

	private List layoutPages = new ArrayList(10);

	private PDDocument pdfOverlay;
	private PDDocument pdfDocument;
	private int pageCount = 0;
	private COSStream saveGraphicsStateStream;
	private COSStream restoreGraphicsStateStream;

	/**
	* This will overlay a document and write out the results.<br/><br/>
	*
	* usage: java org.pdfbox.Overlay <overlay.pdf> <document.pdf> <result.pdf>
	*
	* @param args The command line arguments.
	*
	* @throws IOException If there is an error reading/writing the document.
	* @throws COSVisitorException If there is an error writing the document.
	*/
	public static void main( String[] args ) throws IOException, COSVisitorException
	{
	if( args.length != 3 )
	{
	usage();
	System.exit(1);
	}
	else
	{
	PDDocument overlay = null;
	PDDocument pdf = null;

	try
	{
	overlay = getDocument( args[0] );
	pdf = getDocument( args[1] );
	Overlay overlayer = new Overlay();
	overlayer.overlay( overlay, pdf );
	writeDocument( pdf, args[2] );
	}
	finally
	{
	if( overlay != null )
	{
	overlay.close();
	}
	if( pdf != null )
	{
	pdf.close();
	}
	}
	}
	}

	private static void writeDocument( PDDocument pdf, String filename ) throws IOException, COSVisitorException
	{
	FileOutputStream output = null;
	COSWriter writer = null;
	try
	{
	output = new FileOutputStream( filename );
	writer = new COSWriter( output );
	writer.write( pdf );
	}
	finally
	{
	if( writer != null )
	{
	writer.close();
	}
	if( output != null )
	{
	output.close();
	}
	}
	}

	private static PDDocument getDocument( String filename ) throws IOException
	{
	FileInputStream input = null;
	PDFParser parser = null;
	PDDocument result = null;
	try
	{
	input = new FileInputStream( filename );
	parser = new PDFParser( input );
	parser.parse();
	result = parser.getPDDocument();
	}
	finally
	{
	if( input != null )
	{
	input.close();
	}
	}
	return result;
	}

	private static void usage()
	{
	System.err.println( "usage: java " + Overlay.class.getName() + " <overlay.pdf> <document.pdf> <result.pdf>" );
	}

	/**
	* Private class.
	*/
	private static class LayoutPage
	{
	private final COSBase contents;
	private final COSDictionary res;
	private final Map objectNameMap;

	/**
	* Constructor.
	*
	* @param contentsValue The contents.
	* @param resValue The resource dictionary
	* @param objectNameMapValue The map
	*/
	public LayoutPage(COSBase contentsValue, COSDictionary resValue, Map objectNameMapValue)
	{
	contents = contentsValue;
	res = resValue;
	objectNameMap = objectNameMapValue;
	}
	}

	/**
	* This will overlay two documents onto each other. The overlay document is
	* repeatedly overlayed onto the destination document for every page in the
	* destination.
	*
	* @param overlay The document to copy onto the destination
	* @param destination The file that the overlay should be placed on.
	*
	* @return The destination pdf, same as argument passed in.
	*
	* @throws IOException If there is an error accessing data.
	*/
	public PDDocument overlay( PDDocument overlay, PDDocument destination ) throws IOException
	{
	pdfOverlay = overlay;
	pdfDocument = destination;

	PDDocumentCatalog overlayCatalog = pdfOverlay.getDocumentCatalog();
	collectLayoutPages( overlayCatalog.getAllPages() );

	COSDictionary saveGraphicsStateDic = new COSDictionary();
	saveGraphicsStateStream = new COSStream( saveGraphicsStateDic, pdfDocument.getDocument().getScratchFile() );
	OutputStream saveStream = saveGraphicsStateStream.createUnfilteredStream();
	saveStream.write( " q\n".getBytes() );
	saveStream.flush();

	restoreGraphicsStateStream = new COSStream( saveGraphicsStateDic, pdfDocument.getDocument().getScratchFile() );
	OutputStream restoreStream = restoreGraphicsStateStream.createUnfilteredStream();
	restoreStream.write( " Q\n".getBytes() );
	restoreStream.flush();


	PDDocumentCatalog pdfCatalog = pdfDocument.getDocumentCatalog();
	processPages( pdfCatalog.getAllPages() );

	return pdfDocument;
	}

	private void collectLayoutPages( List pages) throws IOException
	{
	Iterator pagesIter = pages.iterator();
	while( pagesIter.hasNext() )
	{
	PDPage page = (PDPage)pagesIter.next();
	COSBase contents = page.getCOSDictionary().getDictionaryObject( COSName.CONTENTS );
	PDResources resources = page.findResources();
	if( resources == null )
	{
	resources = new PDResources();
	page.setResources( resources );
	}
	COSDictionary res = resources.getCOSDictionary();

	if( contents instanceof COSStream )
	{
	COSStream stream = (COSStream) contents;
	Map objectNameMap = new TreeMap();
	stream = makeUniqObjectNames(objectNameMap, stream);

	layoutPages.add(new LayoutPage(stream, res, objectNameMap));
	}
	else if( contents instanceof COSArray )
	{
	throw new UnsupportedOperationException("Layout pages with COSArray currently not supported.");
	// layoutPages.add(new LayoutPage(contents, res));
	}
	else
	{
	throw new IOException( "Contents are unknown type:" + contents.getClass().getName() );
	}
	}
	}

	private COSStream makeUniqObjectNames(Map objectNameMap, COSStream stream) throws IOException
	{
	ByteArrayOutputStream baos = new ByteArrayOutputStream(10240);

	byte[] buf = new byte[10240];
	int read;
	InputStream is = stream.getUnfilteredStream();
	while ((read = is.read(buf)) > -1)
	{
	baos.write(buf, 0, read);
	}

	buf = baos.toByteArray();
	baos = new ByteArrayOutputStream(buf.length + 100);
	StringBuffer sbObjectName = new StringBuffer(10);
	boolean bInObjectIdent = false;
	boolean bInText = false;
	boolean bInEscape = false;
	for (int i = 0; i<buf.length; i++)
	{
	byte b = buf[i];

	if (!bInEscape)
	{
	if (!bInText && b == '(')
	{
	bInText = true;
	}
	if (bInText && b == ')')
	{
	bInText = false;
	}
	if (b == '\\')
	{
	bInEscape = true;
	}

	if (!bInText && !bInEscape)
	{
	if (b == '/')
	{
	bInObjectIdent = true;
	}
	else if (bInObjectIdent && Character.isWhitespace((char) b))
	{
	bInObjectIdent = false;

	// System.err.println(sbObjectName);
	// String object = sbObjectName.toString();

	String objectName = sbObjectName.toString().substring(1);
	String newObjectName = objectName + "overlay";
	baos.write('/');
	baos.write(newObjectName.getBytes());

	objectNameMap.put(objectName, COSName.getPDFName(newObjectName));

	sbObjectName.delete(0, sbObjectName.length());
	}
	}

	if (bInObjectIdent)
	{
	sbObjectName.append((char) b);
	continue;
	}
	}
	else
	{
	bInEscape = false;
	}

	baos.write(b);
	}

	COSDictionary streamDict = new COSDictionary();
	streamDict.setItem(COSName.LENGTH, new COSInteger(baos.size()));
	COSStream output = new COSStream(streamDict, pdfDocument.getDocument().getScratchFile());
	output.setFilters(stream.getFilters());
	OutputStream os = output.createUnfilteredStream();
	baos.writeTo(os);
	os.close();

	return output;
	}

	private void processPages( List pages ) throws IOException
	{
	Iterator pageIter = pages.iterator();
	while( pageIter.hasNext() )
	{
	PDPage page = (PDPage)pageIter.next();
	COSDictionary pageDictionary = page.getCOSDictionary();
	COSBase contents = pageDictionary.getDictionaryObject( COSName.CONTENTS );
	if( contents instanceof COSStream )
	{
	COSStream contentsStream = (COSStream)contents;
	// System.err.println("stream");

	COSArray array = new COSArray();

	array.add(contentsStream);

	mergePage( array, page );

	pageDictionary.setItem(COSName.CONTENTS, array);
	}
	else if( contents instanceof COSArray )
	{
	COSArray contentsArray = (COSArray)contents;

	mergePage( contentsArray, page );
	}
	else
	{
	throw new IOException( "Contents are unknown type:" + contents.getClass().getName() );
	}
	pageCount++;
	}
	}

	private void mergePage(COSArray array, PDPage page )
	{
	int layoutPageNum = pageCount % layoutPages.size();
	LayoutPage layoutPage = (LayoutPage) layoutPages.get(layoutPageNum);
	PDResources resources = page.findResources();
	if( resources == null )
	{
	resources = new PDResources();
	page.setResources( resources );
	}
	COSDictionary docResDict = resources.getCOSDictionary();
	COSDictionary layoutResDict = layoutPage.res;
	mergeArray(PROC_SET, docResDict, layoutResDict);
	mergeDictionary(COSName.FONT, docResDict, layoutResDict, layoutPage.objectNameMap);
	mergeDictionary(XOBJECT, docResDict, layoutResDict, layoutPage.objectNameMap);
	mergeDictionary(EXT_G_STATE, docResDict, layoutResDict, layoutPage.objectNameMap);

	//we are going to wrap the existing content around some save/restore
	//graphics state, so the result is
	//
	//<save graphics state>
	//<all existing content streams>
	//<restore graphics state>
	//<overlay content>
	array.add(0, saveGraphicsStateStream );
	array.add( restoreGraphicsStateStream );
	array.add(layoutPage.contents);
	}

	/**
	* merges two dictionaries.
	*
	* @param dest
	* @param source
	*/
	private void mergeDictionary(COSName name, COSDictionary dest, COSDictionary source, Map objectNameMap)
	{
	COSDictionary destDict = (COSDictionary) dest.getDictionaryObject(name);
	COSDictionary sourceDict = (COSDictionary) source.getDictionaryObject(name);

	if (destDict == null)
	{
	destDict = new COSDictionary();
	dest.setItem(name, destDict);
	}
	if( sourceDict != null )
	{

	Iterator iterKeys = sourceDict.keyList().iterator();
	while (iterKeys.hasNext())
	{
	COSName key = (COSName) iterKeys.next();
	COSName mappedKey = (COSName) objectNameMap.get(key.getName());
	if (mappedKey == null)
	{
	// object not needet
	continue;
	}

	destDict.setItem(mappedKey, sourceDict.getItem(key));
	}
	}
	}

	/**
	* merges two arrays.
	*
	* @param dest
	* @param source
	*/
	private void mergeArray(COSName name, COSDictionary dest, COSDictionary source)
	{
	COSArray destDict = (COSArray) dest.getDictionaryObject(name);
	COSArray sourceDict = (COSArray) source.getDictionaryObject(name);

	if (destDict == null)
	{
	destDict = new COSArray();
	dest.setItem(name, destDict);
	}

	for (int sourceDictIdx = 0; sourceDict != null && sourceDictIdx<sourceDict.size(); sourceDictIdx++)
	{
	COSBase key = sourceDict.get(sourceDictIdx);
	if (key instanceof COSName)
	{
	COSName keyname = (COSName) key;

	boolean bFound = false;
	for (int destDictIdx = 0; destDictIdx<destDict.size(); destDictIdx++)
	{
	COSBase destkey = destDict.get(destDictIdx);
	if (destkey instanceof COSName)
	{
	COSName destkeyname = (COSName) destkey;
	if (destkeyname.equals(keyname))
	{
	bFound = true;
	break;
	}
	}
	}
	if (!bFound)
	{
	destDict.add(keyname);
	}
	}
	}
	}
	}