PDFlib Cookbook

cookbook

graphics/hierarchical_layers

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/* $Id: hierarchical_layers.java,v 1.4 2013/01/15 10:11:59 stm Exp $
 * Hierarchical layers:
 * Define a layer hierarchy using the parent and child options.
 *
 * Define the layer "Languages" with the layers "English" and "German" and use
 * set_layer_dependency() with the "parent" option to specify a hierarchy 
 * between them. Define the layer "Images" with the layers "RGB" and "Grayscale"
 * and use set_layer_dependency() with the "parent" option to specify a
 * hierarchy between them. Output images and text on the various layers and
 * open the document with the RGB images and English captions visible.
 *
 * Required software: PDFlib/PDFlib+PDI/PPS 9
 * Required data: grayscale and RGB images
 */
package com.pdflib.cookbook.pdflib.graphics;

import com.pdflib.pdflib;
import com.pdflib.PDFlibException;

public class hierarchical_layers
{
    public static void main (String argv[])
    {
    /* This is where the data files are. Adjust as necessary. */
    String searchpath = "../input";
    String outfile = "hierarchical_layers.pdf";
    String title = "Hierarchical Layers";

    pdflib p = null;
    String rgb = "nesrin.jpg";
    String gray = "nesrin_gray.jpg";
    int font, imageRGB, imageGray;
    int layerImage, layerRGB, layerGray, layerLang, layerEN, layerDE;

    try {
        p = new pdflib();

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

        /* This means we must check return values of load_font() etc. */
        p.set_option("errorpolicy=return");

        /* Open the document with the "Layers" navigation tab visible */
        if (p.begin_document(outfile, "openmode=layers") == -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 */
        font = p.load_font("Helvetica", "unicode", "");
        if (font == -1)
            throw new Exception("Error: " + p.get_errmsg());

        /* Load the Grayscale image */
        imageGray = p.load_image("auto", gray, "");
        if (imageGray == -1)
            throw new Exception("Error: " + p.get_errmsg());

        /* Load the RGB image */
        imageRGB = p.load_image("auto", rgb, "");
        if (imageRGB == -1)
            throw new Exception("Error: " + p.get_errmsg());
        
        /* Define all layers which will be used, and their relationships. This
         * should be done before the first page if the layers are used on more
         * than one page.
         */
        
        /* Define the layer "Images" */
        layerImage = p.define_layer("Images", "");
        
        /* Define the layer "RGB" */
        layerRGB = p.define_layer("RGB", "");
        
        /* Define the layer "Grayscale" which is hidden when opening the
         * document or printing it.
         */
        layerGray = p.define_layer("Grayscale", 
            "initialviewstate=false initialprintstate=false");
        
        /* At most one of the "Grayscale" and "RGB" layers will be visible */
        p.set_layer_dependency("Radiobtn", 
            "group={" + layerGray + " " + layerRGB + "}");
        
        /* Make the "Images" layer to be the parent of the "RGB" and "Grayscale"
         * layers
         */
        p.set_layer_dependency("Parent", "parent=" + layerImage + 
            " children={" + layerGray + " " + layerRGB + "}");
            
        /* Define the  layer "Languages" */
        layerLang = p.define_layer("Languages", "");
        
        /* Define the layer "English" */
        layerEN = p.define_layer("English", "");
        
        /* Define the layer "German" which is hidden when opening the document
         * or printing it.
         */
        layerDE = p.define_layer("German",
            "initialviewstate=false initialprintstate=false");
        
        /* At most one of the "English" and "German" layers will be visible */
        p.set_layer_dependency("Radiobtn", "group={" + layerEN + " " +
            layerDE + "}");
        
        /* Make the "Languages" layer to be the parent of the "German" and
         * "English" layers
         */
        p.set_layer_dependency("Parent", "parent=" + layerLang + 
            " children={" + layerEN + " " + layerDE + "}");

        /* Start the page */
        p.begin_page_ext(0, 0, "width=a4.width height=a4.height");

        /* Place the RGB image on the "RGB" layer */
        p.begin_layer(layerRGB);
        p.fit_image(imageRGB, 100, 400, "boxsize={400 300} fitmethod=meet");
        
        /* Place the Grayscale image on the "Grayscale" layer */
        p.begin_layer(layerGray);
        p.fit_image(imageGray, 100, 400, "boxsize={400 300} fitmethod=meet");

        /* Place an English image caption on the "English" layer */
        p.begin_layer(layerEN);
        p.fit_textline("This is the Nesrin image.", 100, 370, "font=" + font +
            " fontsize=20");

        /* Place a German image caption on the "German" layer */
        p.begin_layer(layerDE);
        p.fit_textline("Das ist das Nesrin-Bild.", 100, 370, "font=" + font +
            " fontsize=20");

        p.end_layer();

        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.toString());
        } finally {
            if (p != null) {
                p.delete();
            }
        }
    }
}