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);
        }
    }
}