PDFlib Cookbook

cookbook

graphics/arrows

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/* $Id: arrows.java,v 1.9 2013/01/15 10:11:59 stm Exp $
 * Arrows:
 * Create an arrow using different methods
 *
 * Method I: Draw a simple horizontal arrow.
 * Method II: Draw an arrow with the aid of its unit vector respresentation.
 * Method III: Draw an arrow using coordinate system translation and rotation.
 *
 * Required software: PDFlib/PDFlib+PDI/PPS 9
 * Required data: none
 */
package com.pdflib.cookbook.pdflib.graphics;

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

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

    int startx, starty, stopx, stopy, ahl, ahw, sw;
    double l, angle;
    double x, y, dx, dy;
    double ux, uy, pux, puy;    /* unit vector and its perpendicular */

    pdflib p = null;

    int font;

    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 + " $Revision: 1.9 $");
        
        /* Load the font. */
        font = p.load_font("Helvetica", "unicode", "");
        if (font == -1)
            throw new Exception("Error: " + p.get_errmsg());

        p.begin_page_ext(0, 0, "width=500 height=500");

        /* Method I:
         * Draw a horizontal green arrow from left to right. Start at the given
         * start point located in the middle of the arrow shaft.
         * The following values are given:
         */
        startx = 100;       /* x coordinate of the starting point */
        starty = 100;       /* y coordinate of the starting point */
        stopx = 400;        /* x coordinate of the end point */
        stopy = 100;        /* y coordinate of the end point */
        ahl = 40;           /* arrow head length */
        ahw = 10;           /* arrow head width */
        sw = 20;            /* shaft width */
        l = stopx - startx; /* length of the arrow */

        /* Set the drawing properties */
        p.setlinewidth(5.0);
        p.setcolor("stroke", "rgb", 0.0, 0.5, 0.5, 0.0);
        p.setcolor("fill", "rgb", 1, 1, 1, 0.0);
        p.set_graphics_option("linejoin=1 linecap=1");

        /* Start drawing the arrow */
        p.moveto(startx, starty);

        x = startx;
        y = starty + sw/2;
        p.lineto(x, y);

        x = x + (l - ahl);
        p.lineto(x, y);

        y = y + ahw;
        p.lineto(x, y);

        p.lineto(stopx, stopy);

        y = y - (2*ahw + sw);
        p.lineto(x, y);

        y = y + ahw;
        p.lineto(x, y);

        x = x - (l - ahl);
        p.lineto(x, y);

        y = starty + sw/2;
        p.lineto(x, y);
        p.fill_stroke();

        /* Method II:
         * Draw a non-horizontal pink arrow from left to right. Start at the
         * given start point located in the middle of the arrow shaft.
         * The following values are given:
         */
        startx = 100;       /* x coordinate of the starting point */
        starty = 200;       /* y coordinate of the starting point */
        stopx = 400;        /* x coodingate of the end point */
        stopy = 300;        /* y coordinate of the end point */
        ahl = 40;           /* arrow head length */
        ahw = 20;           /* arrow head width */
        sw = 20;            /* shaft width */

        /* Calculate the unit vector (ux, uy) and its perpendicular
         * (pux, puy)
         */
        dx = stopx - startx;
        dy = stopy - starty;
        l = Math.sqrt(dx*dx + dy*dy);
        ux = dx/l;
        uy = dy/l;
        pux = uy;
        puy = -ux;

        /* Set the drawing properties */
        p.setlinewidth(5.0);
        p.setcolor("stroke", "rgb", 1.0, 0.5, 1.0, 0.0);
        p.setcolor("fill", "rgb", 0.9, 0.8, 0.8, 0.0);
        p.set_graphics_option("linejoin=1 linecap=1");

        /* Start at the given start point located in the middle of the arrow
         * shaft
         */
        p.moveto(startx, starty);

        x = startx + sw/2 * pux;
        y = starty + sw/2 * puy;
        p.lineto(x, y);

        x = x + (l - ahl) * ux;
        y = y + (l - ahl) * uy;
        p.lineto(x, y);

        x = x + ahw * pux;
        y = y + ahw * puy;
        p.lineto(x, y);

        p.lineto(stopx, stopy);

        x = x - (2*ahw + sw) * pux;
        y = y - (2*ahw + sw) * puy;
        p.lineto(x, y);

        x = x + ahw * pux;
        y = y + ahw * puy;
        p.lineto(x, y);

        x = x - (l - ahl) * ux;
        y = y - (l - ahl) * uy;
        p.lineto(x, y);

        x = startx + sw/2 * pux;
        y = starty + sw/2 * puy;
        p.lineto(x, y);

        p.fill_stroke();

        /* Method III:
         * Draw a non-horizontal black arrow from left to right. Start at the
         * given start point located in the middle of the arrow shaft.
         * The following values are given:
         */
        startx = 100;       /* x coordinate of the starting point */
        starty = 300;       /* y coordinate of the starting point */
        angle = 40;         /* Rotation angle in degrees */
        l = 200;            /* length of the arrow */
        ahl = 30;           /* arrow head length */
        ahw = 10;           /* arrow head width */
        sw = 4;             /* shaft width */

        /* Set the drawing properties */
        p.setlinewidth(3.0);
        p.setcolor("stroke", "rgb", 0.0, 0.0, 0.0, 0.0);
        p.setcolor("fill", "rgb", 0.0, 0.0, 0.0, 0.0);
        p.set_graphics_option("linejoin=1 linecap=1");

        /* Rotate and translate the coordinate system */
        p.translate(startx, starty);
        p.rotate(angle);

        /* Start drawing the arrow */
        p.moveto(0, 0);

        x = 0;
        y = sw/2;
        p.lineto(x, y);

        x = x + (l - ahl);
        p.lineto(x, y);

        y = y + ahw;
        p.lineto(x, y);

        x = x + ahl;
        y = y - (ahw + sw/2);
        p.lineto(x, y);

        x = x - ahl;
        y = y - (ahw + sw/2);
        p.lineto(x, y);

        y = y + ahw;
        p.lineto(x, y);

        x = x - (l - ahl);
        p.lineto(x, y);

        y = y + sw/2;
        p.lineto(x, y);
        p.fill_stroke();

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