text_output/invisible_text

 * Invisible text:

 * Output invisible text on top of an image

 * 

 * Place an image and create invisible text on top of it with the

 * "textrendering" parameter set to 3.  The most common scenario for this is

 * "scanned page with invisible OCR text (which has been retrieved from the

 * scanned page in an earlier step with OCR).

 * Required software: PDFlib Lite/PDFlib/PDFlib+PDI/PPS 7

 * Required data: image file

 */

package com.pdflib.cookbook.pdflib.text_output;

import com.pdflib.pdflib;

import com.pdflib.PDFlibException;

public class invisible_text

{

    public static void main (String argv[])

    {

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

    String searchpath = "../input";

    String outfile = "invisible_text.pdf";

    String title = "Invisible Text";

    pdflib p = null;

    String imagefile = "multi_page.tif";

    int font, image;

    try {

        p = new pdflib();

        p.set_parameter("SearchPath", searchpath);

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

        p.set_parameter("errorpolicy", "return");

        if (p.begin_document(outfile, "") == -1)

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

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

        p.set_info("Title", title + " $Revision: 1.4 $");

        /* Load the font; for PDFlib Lite: change "unicode" to "winansi" */

        font = p.load_font("Helvetica", "unicode", "");

        if (font == -1)

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

        /* Load the  image */

        image = p.load_image("auto", imagefile, "page=1");

        if (image == -1)

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

        /* Start page */

        p.begin_page_ext(0, 0, "width=a4.width height=a4.height");

        /* Place the image */

        p.fit_image(image, 0, 0, "boxsize={595 842} fitmethod=meet");

        p.close_image(image);

        /* Save the current graphics state */

        p.save();

        /* Set the text rendering mode to "invisible text" */

        p.set_value("textrendering", 3);

        /* Output the text invisibly on top of the image with the rendering

         * mode set to "invisible text" above. (The text can be output

         * on top of the image or below the image.) The following text

         * resembles text retrieved from the scanned page via OCR.

         */

        p.setfont(font, 21);

        p.show_xy("PDFlib GmbH München, Germany", 130, 750);

        p.show_xy("www.pdflib.com", 215, 710);

        p.setfont(font, 28);

        p.show_xy("Tutorial for", 120, 480);

        p.show_xy("PDFlib, PDI, and PPS", 120, 445);

        p.setfont(font, 21);

        p.show_xy("General Edition for", 195, 125);

        p.show_xy("Cobol, C, C++, Java, Perl", 165, 95);

        p.show_xy("PHP, Phyton, RPG, Ruby, and Tcl", 140, 70);

        /* Restore the current graphics state */

        p.restore();

        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");

        } catch (Exception e) {

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

        } finally {

            if (p != null) {

                p.delete();

            }

        }

    }

}