WalkingText.java Source code

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Here is the source code for WalkingText.java

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/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */

//applet.html

/*
    
<TITLE>Walking Text Demo</TITLE>
<BODY BGCOLOR=White>
<P>Here is a walking text applet.
<APPLET CODE="WalkingText" WIDTH=500 HEIGHT=70>
   <PARAM NAME=Text Value="Learning Tree International">
   <PARAM NAME=FontName Value="Helvetica">
   <PARAM NAME=FontSize Value="24">
</APPLET>
<HR>
<A HREF="WalkingText.java">Use The Source, Luke.</A>
    
*/

import java.applet.Applet;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;

public class WalkingText extends Applet implements Runnable {
    protected String mesg = null;

    protected int xloc, yloc, width, height, textWidth, textHeight;

    protected Thread t;

    protected boolean done = false;

    /** How long to nap for each move */
    protected int napTime = 150;

    /** Applet Initializer */
    public void init() {
        xloc = 0;
        width = getSize().width;
        height = getSize().height;

        if ((mesg = getParameter("text")) == null)
            mesg = "Hello World of Java";

        String pSize = getParameter("fontsize");
        if (pSize == null)
            pSize = "12";

        String fontName = getParameter("fontName");
        if (fontName == null)
            fontName = "Helvetica";

        // System.out.println("Font is " + pSize + " point " + fontName);
        Font f = new Font(fontName, Font.PLAIN, Integer.parseInt(pSize));
        setFont(f);

        FontMetrics fm = getToolkit().getFontMetrics(f);
        textWidth = fm.stringWidth(mesg);
        textHeight = fm.getHeight();
        // System.out.println("TextWidth " + textWidth + ", ht " + textHeight);

        // use textHeight in y coordinate calculation
        yloc = height - ((height - textHeight) / 2);
    }

    /** This is important: we create a thread, so we must kill it */
    public void stop() {
        done = true;
        t = null;
    }

    /** create the thread and start it. */
    public void start() {
        if (t == null)
            t = new Thread(this);
        done = false;
        t.start();
    }

    // Usage:
    public String[][] getParameterInfo() {
        String[][] params = { { "text", "text", "Text to walk across the screen" },
                { "fontName", "text", "Name of font to display in" },
                { "fontsize", "int", "How big to make the text" }, };

        return params;
    }

    /** Run is called by the Thread class when there is work to do */
    public void run() {
        while (!done) {
            if ((xloc += 5) > getSize().width)
                xloc = 0;
            repaint();
            try {
                Thread.sleep(napTime);
            } catch (Exception e) {
                System.out.println("Who dares to interrupt my Sleep()? " + e);
            }
            ;
        }
    }

    /** Paint is called by Applet to redraw the screen */
    public void paint(Graphics g) {
        g.drawString(mesg, xloc, yloc);
        // if ((xloc + textWidth) > getSize().width) {
        //    int negLoc = textWidth-(width-xloc);
        //    System.out.println("xloc, textWidth, negLoc: " + xloc + "," +
        //          textWidth + ", " + negLoc);
        //    g.drawString(mesg, negLoc, yloc);
        // }
    }
}