PDFlib Cookbook

cookbook

graphics/hierarchical_layers

Define a layer hierarchy using the parent and child options.

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/*
 * 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;
	int exitcode = 0;

	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);

	    /* 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.println("PDFlib exception occurred:");
            System.err.println("[" + e.get_errnum() + "] " + e.get_apiname() +
				": " + e.get_errmsg());
	    exitcode = 1;
        } catch (Exception e) {
            System.err.println(e.toString());
	    exitcode = 1;
        } finally {
            if (p != null) {
                p.delete();
            }
	    System.exit(exitcode);
        }
    }
}