PDFlib Cookbook

cookbook

general/metric_topdown_coordinates

Output text using metric coordinates in a topdown coordinate system.

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/*
 * Metric topdown coordinates:
 * Output text using metric coordinates in a topdown coordinate system
 * 
 * Use topdown coordinates starting from the top left instead from the bottom
 * left, scale the coordinate system to use metric coordinates, and place some
 * horizontal lines 1 cm from each other.
 *  
 * Required software: PDFlib/PDFlib+PDI/PPS 9
 * Required data: none
 */
package com.pdflib.cookbook.pdflib.general;

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

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

        pdflib p = null;
        int font;
        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");
            
            if (p.begin_document(outfile, "") == -1)
                throw new Exception("Error: " + p.get_errmsg());

            p.set_info("Creator", "PDFlib Cookbook");
            p.set_info("Title", title);
            
            font = p.load_font("Helvetica", "unicode", "");
            if (font == -1)
                throw new Exception("Error: " + p.get_errmsg());
            
            /* Use topdown coordinates */
            p.set_option("topdown=true");
            
            /* Start an A4 page */
            p.begin_page_ext(0, 0, "width=a4.width height=a4.height");
            
            /* Scale the coordinate system to use metric coordinates.
             * By default, PDFlib will expect incoming coordinates in DTP points 
             * which are defined as: 1 pt = 1/72 inch = 25.4/72 mm = 0.3528 mm.
             * In order to supply the coordinates in centimeters instead of points
             * we have to calculate the scaling factor as follows:
             * (72 points/inch) / (2.54 cm/inch) = 28.3465 points/cm.
             */
            p.scale(28.3465, 28.3465);
            
            /* Now, PDFlib will interpret all coordinates (except for interactive
             * features, see below) in centimeters. The scaling is only in effect
             * for the current page, and must be repeated on each page (if so
             * desired).
             */
            
            /* Interpret all coordinates for hypertext elements in the coordinates
             * defined above as well
             */
            p.set_option("usercoordinates=true");
            
            /* Place some horizontal lines 1 cm from each other. 
             * With the third line, draw a rectangle.
             */
            p.setlinewidth(0.01);
         
            for (int i = 1; i < 29; i++) {
                p.moveto(0, i);
                p.lineto(1, i);
                if (i == 3) {
                    p.rect(0, i, 1, 1);
                }
                    p.fill_stroke();
            }
            
            /* Set the font size in cm */
            p.setfont(font, 0.5);
            
            p.fit_textline("Centimeters from the top left instead of points from " +
                "the bottom left:", 2, 5, "");
            p.fit_textline("The small lines on the left are placed 1 cm from " +
                "each other.", 2, 6, "");
            p.fit_textline("This text line is displayed at 7 cm from top and 2 " +
                "cm from the left.", 2, 7, "");
            
            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);
            exitcode = 1;
        } finally {
            if (p != null) {
                p.delete();
            }
            System.exit(exitcode);
        }
    }
}