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pdfa/transparent_stamp_for_pdfa1

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/*

 * $Id: transparent_stamp_for_pdfa1.java,v 1.6 2016/07/27 09:04:49 stm Exp $

 *

 * Transparent stamp for PDF/A-1:

 * Apply a transparent stamp to an existing PDF/A-1 document while maintaining

 * PDF/A-1 conformance.

 *

 * Import all pages from an existing PDF/A-1 document and place a stamp on the

 * page. The stamp is filled with a pattern color, where the pattern consists of

 * a bitmap. The bitmap is used as a mask to create a certain percentage of

 * transparency. This is required since real transparency is not allowed in

 * PDF/A-1. Transparency by pattern color is PDF/A-1 compatible, so we use it to

 * apply a transparent stamp on a PDF/A-1 document while maintaining PDF/A-1

 * conformance.

 *

 * Note that this trick is only necessary for PDF/A-1, as true PDF

 * transparency is allowed beginning with PDF/A-2.

 *

 * If the transparent stamp is not visible in Acrobat (or is visible only at

 * certain zoom levels) you can set the following in Acrobat X:

 * Edit, Preferences, General, Page Display: disable "Use 2D graphics

 * acceleration" and enable "Smooth images".

 *

 * Required software: PDFlib+PDI/PPS 9.0.2

 * Required data: PDF document

 */

package com.pdflib.cookbook.pdflib.pdfa;


import com.pdflib.pdflib;

import com.pdflib.PDFlibException;


public class transparent_stamp_for_pdfa1

{

    public static void main (String argv[])

    {

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

        String searchpath = "../input";

        String outfile = "transparent_stamp_for_pdfa1.pdf";

        String title = "Transparent Stamp for PDF/A-1";


        pdflib p = null;


        String pdffile = "PLOP-datasheet-PDFA-1b.pdf";

        int indoc, pageno, endpage, page, font, pattern;

        double w;

        double ret;

        String res;

        int image;

        int exitcode = 0;


        /* data set for our halftoning bitmap */

        int data[][] = {

        {   0x00, 0x00,  /* 30% */

            0x00, 0x00,

            0x00, 0x00,

            0x03, 0xC0,

            0x07, 0xE0,

            0x0F, 0xF0,

            0x1F, 0xF8,

            0x1F, 0xF8,

   

            0x1F, 0xF8,

            0x1F, 0xF8,

            0x0F, 0xF0,

            0x07, 0xE0,

            0x03, 0xC0,

            0x00, 0x00,

            0x00, 0x00,

            0x00, 0x00,

        },

        {   0x00, 0x00, /* 20% */

            0x00, 0x00,

            0x00, 0x00,

            0x00, 0x00,

            0x03, 0xC0,

            0x07, 0xE0,

            0x0F, 0xF0,

            0x0F, 0xF0,

   

            0x0F, 0xF0,

            0x0F, 0xF0,

            0x07, 0xE0,

            0x03, 0xC0,

            0x00, 0x00,

            0x00, 0x00,

            0x00, 0x00,

            0x00, 0x00,

        }};

   

        int ht = 1; /* index in halftone array */


        try {

            final int SCALING_FACTOR = 16;

           

            p = new pdflib();


            p.set_option("searchpath={" + searchpath + "}");


            /* This means we must check return values of load_font() etc. */

            p.set_option("errorpolicy=return");


            if (p.begin_document(outfile, "pdfa=PDF/A-1b:2005") == -1)

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


            p.set_info("Creator", "PDFlib Cookbook");

            p.set_info("Title", title + " $Revision: 1.6 $");


            /*

             * Open the input PDF. This must be done before creating the pattern

             * because the output intent must be set before defining the

             * pattern.

             */

            indoc = p.open_pdi_document(pdffile, "");

            if (indoc == -1)

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


            endpage = (int) p.pcos_get_number(indoc, "length:pages");


            /*

             * Since the input document contains its own output intent retrieve

             * the output intent from the input document and copy it to the

             * output document.

             */

            res = p.pcos_get_string(indoc, "type:/Root/OutputIntents");

            if (res.equals("array")) {

                ret = p.process_pdi(indoc, -1, "action=copyoutputintent");

                if (ret == -1)

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

            }


            /*

             * Define a bitmap pattern based on an image mask. We scale down

             * the image to provide a smoother appearance on screen.

             */

            byte[] bitmap = new byte[data[ht].length];

            for (int j = 0; j < data[ht].length; j++)

                bitmap[j] = (byte) data[ht][j];


            p.create_pvf("/pvf/image/bitmap", bitmap, "");


            image = p.load_image("raw", "/pvf/image/bitmap",

                    "bpc=1 components=1 height=16 width=16 invert mask");


            if (image == -1)

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


            w = (double) 16 / SCALING_FACTOR;

           

            pattern = p.begin_pattern_ext(w, w, "");


            p.fit_image(image, 0, 0, "scale=" + (double) 1 / SCALING_FACTOR);


            p.end_pattern();


            p.close_image(image);


            /* Loop over all pages of the input document */

            for (pageno = 1; pageno <= endpage; pageno++) {

                page = p.open_pdi_page(indoc, pageno, "");


                if (page == -1)

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


                /* Dummy page size; will be adjusted later */

                p.begin_page_ext(10, 10, "");


                /*

                 * Place the imported page on the output page, and adjust the

                 * page size.

                 */

                p.fit_pdi_page(page, 0, 0, "adjustpage");


                /*

                 * Load the font for the stamp.

                 */

                font = p.load_font("DejaVuSerif", "unicode", "embedding");


                if (font == -1)

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


                /* Place the stamp, filled with the pattern color */

                p.setcolor("fill", "pattern", pattern, 0, 0, 0);


                p.fit_textline("PUBLISHED", 20, 20, "font=" + font

                        + " fontsize=1 boxsize={550 800} stamp=ll2ur");


                p.close_pdi_page(page);


                p.end_page_ext("");

            }


            p.end_document("");

        }

        catch (PDFlibException e) {

            System.err.print("PDFlib exception occurred:\n");

            System.err.print("[" + e.get_errnum() + "] " + e.get_apiname()

                    + ": " + e.get_errmsg() + "\n");

            exitcode = 1;

        }

        catch (Exception e) {

            System.err.println(e.getMessage());

            exitcode = 1;

        }

        finally {

            if (p != null) {

                p.delete();

            }

            System.exit(exitcode);

        }

    }

}