interchange/image_metadata

package com.pdflib.cookbook.pcos.interchange;

import java.io.File;

import java.io.FileOutputStream;

import java.io.PrintStream;

import com.pdflib.pCOS;

import com.pdflib.pCOSException;

import com.pdflib.cookbook.pcos.pcos_cookbook_example;

/**

 * Retrieve the XMP metadata for all images in the document.

 * <p>

 * The metadata is written to a separate file for each image. The naming

 * convention for the generated files is:

 * <p>

 * &lt;basename of input document&gt;_images[&lt;n&gt;]_Metadata.txt

 * <p>

 * with &lt;n&gt; being the index of the image in the "images" array.

 * <p>

 * Required software: pCOS interface 3 (pCOS 2.x, PDFlib 7.x, TET 2.2,

 * PLOP 3.x)<br>

 * Required data: PDF document with images that have XMP metadata attached

 *

 * @version  $Id: image_metadata.java,v 1.5 2008/07/08 13:00:07 stm Exp $

 */

public class image_metadata extends pcos_cookbook_example {

   

    /* This is where the data files are. Adjust as necessary. */

    private final static String SEARCH_PATH = "../input";

    public void example_code(pCOS p, String filename) throws pCOSException, Exception {

        /* Open the PDF document */

        int doc = p.open_document(filename, "");

        if (doc == -1)

            throw new Exception("Error: " + p.get_errmsg());

       

        System.out.println("File name: " + p.get_string(doc, "filename"));

       

        /*

         * Loop over all images in the document and check whether there is

         * a Metadata stream attached. If a Metadata stream is found,

         * the contents are dumped to a file.

         */

        int imagecount = (int) p.get_number(doc, "length:images");

        for (int i = 0; i < imagecount; i += 1) {

            String image_path = "images[" + i + "]/Metadata";

           

            String objtype = p.get_string(doc, "type:" + image_path);

           

            if (objtype.equals("stream")) {

                xmp_dump(p, doc, filename, i, image_path);

            }

        }

       

        p.close_document(doc);

    }

   

    private void xmp_dump(pCOS p, int doc, String filename,

                             int i, String image_path) throws Exception {

        /*

         * Strip relative pathname and ".pdf" suffix from input filename.

         */

        File path = new File(filename);

        String basename = strip_suffix(path.getName());

       

        /*

         * Create an output filename that has blanks and forward slashes

         * replaced with underscores

         */

        String output_filename =

            (basename + "_" + image_path + ".txt").replaceAll("[ \\/]", "_");

       

        System.out.println("Writing metadata of image " + i + " to file \""

            + output_filename + "\" ...");

       

        byte[] contents = p.get_stream(doc, "", image_path);

       

        PrintStream output_file = new PrintStream(new FileOutputStream(output_filename));

        output_file.write(contents);

        output_file.close();

    }

    private String strip_suffix(String filename) {

        int dot_index = filename.lastIndexOf('.');

       

        return dot_index > 0 ? filename.substring(0, dot_index) : filename;

    }

    public image_metadata(String[] argv, String readable_name,

        String search_path, String full_rcs_file_name, String revision) {

        super(argv, readable_name, search_path, full_rcs_file_name, revision);

    }

    public static void main(String argv[]) {

        image_metadata example = new image_metadata(argv,

            "Image XMP metadata", SEARCH_PATH,

            "$RCSfile: image_metadata.java,v $", "$Revision: 1.5 $");

        example.execute();

    }

}