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cookbook

text_output/keep_lines_together

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/* $Id: keep_lines_together.java,v 1.6 2013/01/15 10:12:08 stm Exp $
 * Keep lines together:
 * Control the lines kept together on the page
 * 
 * Use the inline option "mark" of add/create_textflow() to mark certain 
 * positions in the Textflow. Use the "returnatmark" option fit_textflow() to
 * return prematurely at the text position where the inline option "mark" has
 * been defined with the specified number. The return reason string will be
 * "_mark#", where # is the number of the appropriate mark.
 * Use this feature to ensure that the text between two marks is always kept 
 * together in one fitbox. 
 *
 * Required software: PDFlib/PDFlib+PDI/PPS 9
 * Required data: none
 */
package com.pdflib.cookbook.pdflib.text_output;

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

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

    pdflib p = null;
    int tf = -1;
    
    final int ystart = 700;
    final int boxwidth = 210, boxheight = 110;
    final int offset = 10;
    final int xleft = 10;
    final int xright = xleft + boxwidth + 80;
    
    String result, optlist;
    int lastmark = 0;
    int y = ystart;
    
    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");
        
        /* Set an output path according to the name of the topic */
        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: 1.6 $");

        /* Text to be created. 
         * Soft hyphens are indicated with the character reference "­"
         * (character references are enabled by the "charref" option).
         * The inline option "mark" is used to indicated text which should not
         * be divided, i.e. all text between an equal and an odd mark number
         * should be kept together in one fitbox.
         */
        final String text =
            "<mark=0>Have a look at our new paper plane models!" +
            "<mark=1>" +
            "<mark=2><nextline fillcolor={rgb 0.5 0.0 0.0}>Long Distance Glider:<nextline>" +
            "With this paper rocket you can send all your messages even when " +
            "sitting in a hall or in the cinema pretty near the back." +
            "<mark=3>" +
            "<mark=4><nextline fillcolor={rgb 0.0 0.5 0.0}>Giant Wing:<nextline>" +
            "An unbelievable sailplane! It is ama&shy;zingly robust and can " +
            "even do aero&shy;batics. But it best suited to gliding." +
            "<mark=5>" +
            "<mark=6><nextline fillcolor={rgb 0.8 0.4 0.1}>Cone Head Rocket:<nextline>" +
            "This paper arrow can be thrown with big swing. We launched it " +
            "from the roof of a hotel. It stayed in the air a long time and " +
            "covered a considerable distance." +
            "<mark=7>" +
            "<mark=8><nextline fillcolor={rgb 0.0 0.5 0.5}>Super Dart:<nextline>" +
            "The super dart can fly giant loops with a radius of 4 or 5 " +
            "metres and cover very long distances. Its heavy cone point is " +
            "slightly bowed upwards to get the lift required for loops." +
            "<mark=9>" +
            "<mark=10><nextline fillcolor={rgb 0.0 0.0 0.5}>German Bi-Plane:<nextline>" +
            "Brand-new and ready for take-off. If you have lessons in the " +
            "history of aviation you can show your interest by letting it " +
            "land on your teacher's desk.<mark=11>";
        
        /* Maximum number of the mark defined in the Textflow */
        int maxmark = 11;
        
        p.begin_page_ext(0, 0, "width=a4.width height=a4.height");
        
        /* Output some descriptive text */
        String topts = "fontname=Helvetica-Bold fontsize=14 encoding=unicode ";
            
        p.fit_textline("Fit Textflow without considering", 
            xleft, y + 30, topts);
        p.fit_textline("marks", xleft, y + 15, topts);
        p.fit_textline("Fit Textflow using \"returnatmark\"", xright, y + 30,
            topts);
        p.fit_textline("to keep lines together", xright, y + 15, topts);
        
        /* Option list to create the Textflow.
         * "avoidemptybegin" deletes empty lines at the beginning of a fitbox.
         * "charref" enables the substitution of numeric and character entity
         * or glyph name references, e.g. of the character reference "&shy;"
         * for a soft hyphen.
         */
        optlist = "fontname=Helvetica fontsize=12 encoding=unicode " +
            "alignment=justify leading=120% charref avoidemptybegin";
             
        /* ------------------------------------------------------------------
         * First, output the text without considering any marks, i.e. without
         * keeping lines together
         * ------------------------------------------------------------------
         */
        
        /* Create the Textflow */
        tf = p.create_textflow(text, optlist);
        if (tf == -1)
            throw new Exception("Error: " + p.get_errmsg());
        
        do
        {
            /* Set the line width used for the border around the fitbox of the 
             * Textflow displayed with the "showborder" option.
             */
            p.setlinewidth(0.3);
            
            /* Fit the Textflow */
            result = p.fit_textflow(tf, xleft, y, xleft + boxwidth, 
                y - boxheight, "showborder");
            
            y -= boxheight + offset;
                                  
        /* "_stop" means that the Textflow has been fit completely */
        } while (!result.equals("_stop") &&
                 !result.equals("_boxempty"));
        
        /* -------------------------------------------------------------------
         * Now, output the text with keeping lines together by considering the 
         * marks
         * -------------------------------------------------------------------
         */
        
        /* Create the Textflow again */
        tf = p.create_textflow(text, optlist);
        if (tf == -1)
            throw new Exception("Error: " + p.get_errmsg());
        
        /* Set the starting point for the first fitbox */
        y = ystart;
        
        /* Loop until all of the text is placed; create new fitboxes on the
         * page as long as more text needs to be placed.
         */
        do
        {
            /* Set the line width used for the border around the fitbox of the 
             * Textflow displayed with the "showborder" option.
             */
            p.setlinewidth(0.3);
            
            /* Option list for fitting the Textflow.
             * "showborder" is used to illustrate the fitbox borders for
             * testing.
             * "blind" is used to fit the Textflow in "blind" mode. All 
             * calculations will be done but the Textflow will not actually be
             * placed.
             */
            optlist = "showborder blind";
            
            /* Fit the Textflow in "blind" mode to find out up to which mark
             * the text will fit into the fitbox.
             */
            result = p.fit_textflow(tf, xright, y, xright + boxwidth, 
                y - boxheight, optlist);
            
            lastmark = (int) p.info_textflow(tf, "lastmark");
            
            /* An even mark number indicates the start of a text section to be
             * kept together. Reset it to the last odd mark number which 
             * indicates the end of a text section.
             */
            if (lastmark%2 == 0) {
                --lastmark;
            }
                        
            /* Now actually fit the Textflow. To rewind the Textflow status
             * to before the last call to fit_textflow() use "rewind=-1".
             */
            optlist = "showborder returnatmark=" + lastmark + " rewind=-1";
            result = p.fit_textflow(tf, xright, y, xright + boxwidth, 
                y - boxheight, optlist);
            
            y -= boxheight + offset;
                                  
        /* _stop means that the Textflow has been fit completely.
         * _mark# with # equals "maxmark" defined above means that the maximum
         * mark number defined in the Textflow has been reached.
         */
        } while (!result.equals("_stop") &&
                 !result.equals("_boxempty") &&
                 !result.equals("_mark" + maxmark));
        
        /* _boxempty" happens if the box is too small to hold any text */
        if (result.equals( "_boxempty")) {
            throw new Exception ("Error: Textflow box too small");
        }
        
        p.end_page_ext("");
            
        p.delete_textflow(tf);
        
        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();
            }
        }
    }
}