path: root/src/org/apache/fop/pdf/PDFDocument.java

/*-- $Id$ -- 

 ============================================================================
                   The Apache Software License, Version 1.1
 ============================================================================
 
    Copyright (C) 1999 The Apache Software Foundation. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modifica-
 tion, are permitted provided that the following conditions are met:
 
 1. Redistributions of  source code must  retain the above copyright  notice,
    this list of conditions and the following disclaimer.
 
 2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.
 
 3. The end-user documentation included with the redistribution, if any, must
    include  the following  acknowledgment:  "This product includes  software
    developed  by the  Apache Software Foundation  (http://www.apache.org/)."
    Alternately, this  acknowledgment may  appear in the software itself,  if
    and wherever such third-party acknowledgments normally appear.
 
 4. The names "Fop" and  "Apache Software Foundation"  must not be used to
    endorse  or promote  products derived  from this  software without  prior
    written permission. For written permission, please contact
    apache@apache.org.
 
 5. Products  derived from this software may not  be called "Apache", nor may
    "Apache" appear  in their name,  without prior written permission  of the
    Apache Software Foundation.
 
 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 FITNESS  FOR A PARTICULAR  PURPOSE ARE  DISCLAIMED.  IN NO  EVENT SHALL  THE
 APACHE SOFTWARE  FOUNDATION  OR ITS CONTRIBUTORS  BE LIABLE FOR  ANY DIRECT,
 INDIRECT, INCIDENTAL, SPECIAL,  EXEMPLARY, OR CONSEQUENTIAL  DAMAGES (INCLU-
 DING, BUT NOT LIMITED TO, PROCUREMENT  OF SUBSTITUTE GOODS OR SERVICES; LOSS
 OF USE, DATA, OR  PROFITS; OR BUSINESS  INTERRUPTION)  HOWEVER CAUSED AND ON
 ANY  THEORY OF LIABILITY,  WHETHER  IN CONTRACT,  STRICT LIABILITY,  OR TORT
 (INCLUDING  NEGLIGENCE OR  OTHERWISE) ARISING IN  ANY WAY OUT OF THE  USE OF
 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 This software  consists of voluntary contributions made  by many individuals
 on  behalf of the Apache Software  Foundation and was  originally created by
 James Tauber <jtauber@jtauber.com>. For more  information on the Apache 
 Software Foundation, please see <http://www.apache.org/>.
 
 */
/* image support modified from work of BoBoGi */

package org.apache.fop.pdf;

// images are the one place that FOP classes outside this package get
// referenced and I'd rather not do it
import org.apache.fop.image.FopImage;

// Java
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Vector;
							   
/**
 * class representing a PDF document. 
 *
 * The document is built up by calling various methods and then finally
 * output to given filehandle using output method.
 *
 * A PDF document consists of a series of numbered objects preceded by a
 * header and followed by an xref table and trailer. The xref table
 * allows for quick access to objects by listing their character
 * positions within the document. For this reason the PDF document must
 * keep track of the character position of each object.  The document
 * also keeps direct track of the /Root, /Info and /Resources objects.
 */
public class PDFDocument {

    /** the version of PDF supported */
    protected static final String pdfVersion = "1.2";

    /** the current character position */
    protected int position = 0;

    /** the character position of each object */
    protected Vector location = new Vector();

    /** the counter for object numbering */
    protected int objectcount = 0;

    /** the objects themselves */
    protected Vector objects = new Vector();

    /** character position of xref table */
    protected int xref;

    /** the /Root object */
    protected PDFRoot root;

    /** the /Info object */
    protected PDFInfo info;

    /** the /Resources object */
    protected PDFResources resources;
    
    protected int xObjectCount = 0;
    protected Vector xObjects = new Vector();

    /**
     * creates an empty PDF document
     */
    public PDFDocument() {

	/* create the /Root, /Info and /Resources objects */
	this.root = makeRoot();
	this.info = makeInfo();
	this.resources = makeResources();
    }
    
    /**
     * set the producer of the document
     *
     * @param producer string indicating application producing the PDF
     */
    public void setProducer(String producer) {
	this.info.setProducer(producer);
    }

    /**
     * make /Root object as next object
     *
     * @return the created /Root object
     */
    protected PDFRoot makeRoot() {

	/* create a PDFRoot with the next object number and add to
	   list of objects */
	PDFRoot pdfRoot = new PDFRoot(++this.objectcount);
	this.objects.addElement(pdfRoot);

	/* create a new /Pages object to be root of Pages hierarchy
	   and add to list of objects */
	PDFPages rootPages = new PDFPages(++this.objectcount);
	this.objects.addElement(rootPages);
	
	/* inform the /Root object of the /Pages root */
	pdfRoot.setRootPages(rootPages);
	return pdfRoot;
    }

    /**
     * make an /Info object
     *
     * @param producer string indicating application producing the PDF
     * @return the created /Info object
     */
    protected PDFInfo makeInfo() {

	/* create a PDFInfo with the next object number and add to
	   list of objects */
	PDFInfo pdfInfo = new PDFInfo(++this.objectcount);
	this.objects.addElement(pdfInfo);
	return pdfInfo;
    }

    /**
     * make a /Resources object
     *
     * @return the created /Resources object
     */
    private PDFResources makeResources() {

	/* create a PDFResources with the next object number and add
	   to list of objects */
	PDFResources pdfResources = new PDFResources(++this.objectcount);
	this.objects.addElement(pdfResources);
	return pdfResources;
    }

    /**
     * make a Type1 /Font object
     * 
     * @param fontname internal name to use for this font (eg "F1")
     * @param basefont name of the base font (eg "Helvetica")
     * @param encoding character encoding scheme used by the font
     * @return the created /Font object
     */
    public PDFFont makeFont(String fontname, String basefont,
			    String encoding) {

	/* create a PDFFont with the next object number and add to the
	   list of objects */
	PDFFont font = new PDFFont(++this.objectcount, fontname,
				   basefont, encoding);
	this.objects.addElement(font);
	return font;
    }

    public int addImage(FopImage img) {
	PDFXObject xObject = new PDFXObject(++this.objectcount,
					    ++this.xObjectCount, img);
	this.objects.addElement(xObject);
	this.xObjects.addElement(xObject);
	return xObjectCount;
    }

    /**
     * make a /Page object
     *
     * @param resources resources object to use
     * @param contents stream object with content
     * @param pagewidth width of the page in points
     * @param pageheight height of the page in points
     * @return the created /Page object
     */
    public PDFPage makePage(PDFResources resources,
			    PDFStream contents, int pagewidth,
			    int pageheight)  {

	/* create a PDFPage with the next object number, the given
	   resources, contents and dimensions */
	PDFPage page = new PDFPage(++this.objectcount, resources,
				   contents, pagewidth, pageheight);

	/* add it to the list of objects */
	this.objects.addElement(page);

	/* add the page to the Root */
	this.root.addPage(page);

	return page;
    }

    /**
     * make a stream object
     *
     * @return the stream object created
     */
    public PDFStream makeStream() {
    
	/* create a PDFStream with the next object number and add it
	   to the list of objects */
	PDFStream obj = new PDFStream(++this.objectcount);
	this.objects.addElement(obj);
	return obj;
    }

    /**
     * get the /Resources object for the document
     *
     * @return the /Resources object
     */
    public PDFResources getResources() {
	return this.resources;
    }

    /**
     * write the entire document out
     *
     * @param writer the PrinterWriter to output the document to
     */
    public void output(PrintWriter writer) throws IOException {

	/* output the header and increment the character position by
	   the header's length */
	this.position += outputHeader(writer);

	this.resources.setXObjects(xObjects);

	/* loop through the object numbers */
	for (int i=1; i <= this.objectcount; i++) {

	    /* add the position of this object to the list of object
	       locations */
	    this.location.addElement(new Integer(this.position));

	    /* retrieve the object with the current number */
	    PDFObject object = (PDFObject)this.objects.elementAt(i-1);

	    /* output the object and increment the character position
	       by the object's length */
	    this.position += object.output(writer);
	}

	/* output the xref table and increment the character position
	   by the table's length */
	this.position += outputXref(writer);

	/* output the trailer and flush the Writer */
	outputTrailer(writer);
	writer.flush();
    }

    /**
     * write the PDF header
     *
     * @param writer the PrintWriter to write the header to
     * @return the number of characters written
     */
    protected int outputHeader(PrintWriter writer) throws IOException {
	String pdf = "%PDF-" + this.pdfVersion + "\n";
	writer.write(pdf);
	return pdf.length();
    }

    /**
     * write the trailer
     *
     * @param writer the PrintWriter to write the trailer to
     */
    protected void outputTrailer(PrintWriter writer) throws IOException {

	/* construct the trailer */
	String pdf = "trailer\n<<\n/Size " + (this.objectcount+1)
	    + "\n/Root " + this.root.number + " " + this.root.generation
	    + " R\n/Info " + this.info.number + " " 
	    + this.info.generation + " R\n>>\nstartxref\n" + this.xref 
	    + "\n%%EOF\n";

	/* write the trailer */
	writer.write(pdf);
    }

    /**
     * write the xref table
     *
     * @param writer the PrintWriter to write the xref table to
     * @return the number of characters written
     */
    private int outputXref(PrintWriter writer) throws IOException {

	/* remember position of xref table */
	this.xref = this.position;

	/* construct initial part of xref */
	StringBuffer pdf = new StringBuffer("xref\n0 " + (this.objectcount+1) 
	    + "\n0000000000 65535 f \n");

	/* loop through object numbers */
	for (int i=1; i < this.objectcount+1; i++) {

	    /* contruct xref entry for object */
	    String padding = "0000000000";
	    String x = this.location.elementAt(i-1).toString();
	    String loc = padding.substring(x.length()) + x;

	    /* append to xref table */
	    pdf = pdf.append(loc + " 00000 n \n");
	}

	/* write the xref table and return the character length */
	writer.write(pdf.toString());
	return pdf.length();
    }
}