/*
** TextBurst sample applet
**
** by (c) Copyright 2001 Simon Huggins
** 
** For demonstration purposes only.
**
** You may use this applet on your web site, but it cannot be
** sold in either its original or altered state.
** This original notice must be included in all versions of
** the applet distributed, even if altered.
**
** The author accepts no liability for any difficulties or loss
** arising from use of this applet. It is primarily intended for
** demonstration purposes.
**
** Change History
** ~~~~~~~~~~~~~~
** 17-Sep-2001  v1.0  Release version
** 24-Sep-2001  v1.1  Alter speed
*/


/*
** Import section - tells the compiler where to look for different classes
** used within this file
*/
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;


/*
** Defines a class called TextBurst which takes the basic JApplet
** class as a template, and adds to it to create our Applet.
** It also implements something called ActionListener which is an
** Interface for the purposes of checking when an event has occurred.
*/
public class TextBurst extends JApplet implements ActionListener {

  static int maxChangeAmount = 20; // Constant value to define the
                                   // max. speed of colour change

  Timer timer;  // Used to update the display ever 50ms
  JLabel theLabel; // The label that shows the text
  int fontSize = 2; // Initial font size (in points)
  int fontDirection = -1; //How much the font size will shrink (minus) or grow by
  int maxFontSize; // Maximum font size
  int redAmount = maxChangeAmount;
  int redDirection = - Math.round((float)(Math.random() * maxChangeAmount + 1));
  int greenAmount = maxChangeAmount;
  int greenDirection = - Math.round((float)(Math.random() * maxChangeAmount + 1));
  int blueAmount = maxChangeAmount;
  int blueDirection = - Math.round((float)(Math.random() * maxChangeAmount + 1));
  Color appletBgColor;  //background color for the applet
  int timerSpeed = 80;  // Timer will start at 80ms

  /*
  ** Initialize the applet - i.e. set up any values before processing begins
  */
  public void init() {
    String burstText = getParameter("burstText"); // get the text parameter from the HTML page

    String timerSpeedString = getParameter("timerSpeed");
    if (timerSpeedString != null)  // check if the parameter was used
      timerSpeed = Integer.parseInt(timerSpeedString);  // if so, convert it to an integer
    else timerSpeed = 80;  // if not, use 80 as a default.
    timer = new Timer(timerSpeed, this); // Define a timer so actionPerformed gets called

    String fontSizeString = getParameter("maxfont"); // get font size as a string from HTML
    if (fontSizeString != null)  // check if the parameter was used
      maxFontSize = Integer.parseInt(fontSizeString);  // if so, convert it to an integer
    else maxFontSize = 20;  // if not, use 20 as a default.

    String appletColorStr = getParameter("bgcolor"); // get color as a string from HTML
    if (appletColorStr != null) { // check if parameter used
      appletBgColor = new Color(Integer.decode(appletColorStr).intValue()); //decode hex
    }
    else appletBgColor = Color.lightGray;  // if not, use light grey.

    theLabel = new JLabel(burstText,SwingConstants.CENTER); // Define a centred label
    theLabel.setForeground(new Color(redAmount,greenAmount,blueAmount)); // Set its colour
    theLabel.setFont(new Font("Helvetica",Font.BOLD,fontSize)); // and its font type
    getContentPane().setBackground(appletBgColor); // Set the Applet's background color
    getContentPane().add(theLabel,BorderLayout.CENTER); // and add it to the applet
  }

  /*
  ** Defines what should happen when the applet starts - e.g. after return to page
  */
  public void start() {
    if (!timer.isRunning()) timer.start(); // start the timer running
  }

  /*
  **Defines what should happen when the applet stops - e.g. when leave the page
  */
  public void stop() {
    if (timer.isRunning()) timer.stop(); // and stop it again
  }

  /*
  ** ActionListener Interface method called by the Timer every 50ms
  */
  public void actionPerformed(ActionEvent e) {
    /* If the font size reaches 20 or 2, reverse the direction of shrinking / growing */
    if ((fontSize==maxFontSize) || (fontSize==2)) fontDirection = -fontDirection;
    fontSize += fontDirection; // shrink or grow the fontSize by this amount
    theLabel.setFont(new Font("Helvetica",Font.BOLD,fontSize)); // change the font size

    /* These sections change the three colours in a similar way to the font size */
    redAmount += redDirection;
    if ((redAmount<=10) || (redAmount>=250)) {
      redDirection = -redDirection; redAmount += redDirection;
    }
    greenAmount += greenDirection;
    if ((greenAmount<=10) || (greenAmount>=250)) {
      greenDirection = -greenDirection; greenAmount += greenDirection;
    }
    blueAmount += blueDirection;
    if ((blueAmount<=10) || (blueAmount>=250)) {
      blueDirection = -blueDirection; blueAmount += blueDirection;
    }
    theLabel.setForeground(new Color(redAmount,greenAmount,blueAmount)); // set the colour
  }

  /*
  ** Define information about the applet - in Appletviewer, see Applet | Info menu
  */
  public String getAppletInfo() {
    return "Title: TextBurst\nAuthor: Simon Huggins\nDisplays a text burst effect"; }

}