PDFlib Cookbook

cookbook

graphics/arrows

Create an arrow using different methods.

Download Java Code  Switch to PHP Code  Show Output 

/*
 * 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 */
        int exitcode = 0;

        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);
            
            /* 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.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);
        }
    }
}