/*-------------------------------------------------------------------*
 * NTU Student: Java With Engineering Applications, Spring 1999
 * Assignment # 7 - Java How To Program 2nd edition, Deitel & Deitel
 * Problem 14.20 on page 764 - CLASS Sign: applet created to 
 * practice loading and displaying multiple image files using the 
 * Media Tracker.
 *
 * This excercise contains extra work above and beyond
 * the problem statement. It also demonstrates the image going off one 
 * side as it appears at the other.
 *
 * Michael Kusmierz
 * Xerox Corporation
 * Rev 1.0	June 3, 1999 
 *
 * This code represents a students work in progress 
 * and is not to be used beyond that purpose.
 *-------------------------------------------------------------------*/ 

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

/**
 * This type was created in VisualAge.
 */
public class Sign extends Applet implements ActionListener, Runnable {
	private Button ivjBtnStop = null;
	private Label ivjLabel1 = null;
	private Label ivjLabel2 = null;
	private TextField ivjTxtFldSleepTime = null;
	private TextField ivjTxtFldStepSize = null;
	private Button ivjButImages = null;
	
	// Sign is derived from the example Fig. 14.5: DeitelLoop4.java
	// Many changes have been made.
	// Load one or more into the array of images, loop through the array,
	// and display each image. It has been modified to load one image and
	// paint them floating across the screen from right to left.

	private Image myImage[];
	private int totalImages = 2;	// total number of images
	private int currentImage = 0;	// current image subscript
	private int sleepTime = 50;			// milliseconds to sleep
	//--- The next two objects are for double-buffering
	private Graphics gContext; 		// off-screen graphics context 
	private Image buffer; 			// buffer in which to draw image
	private MediaTracker imageTracker; // used to track images
	private Thread animate; 		// animation thread
	private boolean stopSign;
	//--- added these to enable the maquee to be sized and
	//    move across the screen.
	private int intPos; 		// display position changes in paint
	private int intSecPos; 		// display following first for wrap around effect
	private int intWidth = 1050; // sign letter width
	private int intHeight = 120;
	private int intStep;

/**
 * This method performs actions based on the button clicked.
 * @param e java.awt.event.ActionEvent
 */
public void actionPerformed(ActionEvent e) {
	if (e.getSource() == ivjBtnStop) {
		stop();
	} else
		if (e.getSource() == ivjButImages) {
			if (totalImages == 2) {
				totalImages = 1;
				showStatus("One image file selected: Oops.jpg");
			} else {
				totalImages = 2;
				showStatus("Two images files selected gives the effect of blinking lights: Oops1.jpg, Oops2.jpg");
			}
		} else {
			try {
				if (e.getSource() == ivjTxtFldSleepTime) {
					sleepTime = Integer.parseInt(ivjTxtFldSleepTime.getText());
				} else
					if (e.getSource() == ivjTxtFldStepSize) {
						intStep = Integer.parseInt(ivjTxtFldStepSize.getText());
					}
			} catch (Throwable exception) {
				showStatus("INVALID ENTRY NUMBER!!! ");
			}
		}
}
/**
 * Gets the applet information.
 * @return java.lang.String
 */
public String getAppletInfo() {
	return "Sign created using VisualAge for Java.";
}
/**
 * Return the BtnStop property value.
 * @return java.awt.Button
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private Button getBtnStop() {
	if (ivjBtnStop == null) {
		try {
			ivjBtnStop = new java.awt.Button();
			ivjBtnStop.setName("BtnStop");
			ivjBtnStop.setBounds(14, 122, 288, 23);
			ivjBtnStop.setLabel("Test of stop( ) to simulate viewer leaving the page.");
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjBtnStop;
}
/**
 * Return the ButImages property value.
 * @return java.awt.Button
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private Button getButImages() {
	if (ivjButImages == null) {
		try {
			ivjButImages = new java.awt.Button();
			ivjButImages.setName("ButImages");
			ivjButImages.setBounds(540, 122, 216, 23);
			ivjButImages.setLabel("Two Image files (default) or One");
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjButImages;
}
/**
 * Return the Label1 property value.
 * @return java.awt.Label
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private Label getLabel1() {
	if (ivjLabel1 == null) {
		try {
			ivjLabel1 = new java.awt.Label();
			ivjLabel1.setName("Label1");
			ivjLabel1.setText("Sleep Adjustment (ms)");
			ivjLabel1.setBounds(313, 122, 125, 23);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjLabel1;
}
/**
 * Return the Label2 property value.
 * @return java.awt.Label
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private Label getLabel2() {
	if (ivjLabel2 == null) {
		try {
			ivjLabel2 = new java.awt.Label();
			ivjLabel2.setName("Label2");
			ivjLabel2.setText("Step Size");
			ivjLabel2.setBounds(488, 122, 52, 23);
			ivjLabel2.setVisible(false);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjLabel2;
}
/**
 * Return the TextField1 property value.
 * @return java.awt.TextField
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private TextField getTxtFldSleepTime() {
	if (ivjTxtFldSleepTime == null) {
		try {
			ivjTxtFldSleepTime = new java.awt.TextField();
			ivjTxtFldSleepTime.setName("TxtFldSleepTime");
			ivjTxtFldSleepTime.setText("50");
			ivjTxtFldSleepTime.setBounds(441, 122, 39, 23);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjTxtFldSleepTime;
}
/**
 * Return the TextField2 property value.
 * @return java.awt.TextField
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private TextField getTxtFldStepSize() {
	if (ivjTxtFldStepSize == null) {
		try {
			ivjTxtFldStepSize = new java.awt.TextField();
			ivjTxtFldStepSize.setName("TxtFldStepSize");
			ivjTxtFldStepSize.setText("10");
			ivjTxtFldStepSize.setBounds(541, 122, 43, 23);
			ivjTxtFldStepSize.setEditable(false);
			ivjTxtFldStepSize.setVisible(false);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjTxtFldStepSize;
}
/**
 * Called whenever the part throws an exception.
 * @param exception java.lang.Throwable
 */
private void handleException(Throwable exception) {

	/* Uncomment the following lines to print uncaught exceptions to stdout */
	// System.out.println("--------- UNCAUGHT EXCEPTION ---------");
	// exception.printStackTrace(System.out);
}
/**
 * Handle the Applet init method.
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
public void init() {
	super.init();
	try {
		setName("BtnStart");
		setLayout(null);
		setSize(928, 156);
		add(getBtnStop(), getBtnStop().getName());
		add(getTxtFldSleepTime(), getTxtFldSleepTime().getName());
		add(getTxtFldStepSize(), getTxtFldStepSize().getName());
		add(getLabel1(), getLabel1().getName());
		add(getLabel2(), getLabel2().getName());
		add(getButImages(), getButImages().getName());
		// user code begin {1}
		
		ivjBtnStop.addActionListener(this);		//stop button
		stopSign = false;
		ivjTxtFldSleepTime.addActionListener(this);
		ivjButImages.addActionListener(this);	//single image option button
		
		//--- viewable but not available to the user at this release
		ivjTxtFldStepSize.addActionListener(this);

		//--- load the image ((s) if there are more then one) 
		//--  when the applet begins executing.
		
		totalImages = 2;
		
		intPos = intWidth;
		intSecPos = intPos + intWidth;
		myImage = new Image[totalImages];
		buffer = createImage(intWidth, intHeight);	// create image buffer
		gContext = buffer.getGraphics(); 			// get graphics context
		sleepTime = 50;								// sleep time in the run loop
		intStep = 10;								// increment buffer display
		
		//--- set background of buffer to white
		gContext.setColor(Color.white);
		gContext.fillRect(0, 0, intWidth, intHeight);
		imageTracker = new MediaTracker(this);
		for (int i = 0; i < myImage.length; i++) {

			myImage[i] = getImage(getDocumentBase(), "images/OOPS" + i + ".JPG");
			showStatus (" File Load: " +getDocumentBase()+ "images/OOPS" + i + ".JPG"); 
			//--- track loading image
			imageTracker.addImage(myImage[i], i);
		}
		try {
			imageTracker.waitForID(0);
		} catch (InterruptedException e) {
			showStatus (" InterruptedException Getting File: " +getDocumentBase()+ "images/OOPS x " +  ".JPG");
		}

		// user code end
	} catch (java.lang.Throwable ivjExc) {
		// user code begin {2}
		// user code end
		handleException(ivjExc);
	}
}
/**
 * main entrypoint - starts the part when it is run as an application
 * @param args java.lang.String[]
 */
public static void main(java.lang.String[] args) {
	try {
		Frame frame;
		try {
			Class aFrameClass = Class.forName("com.ibm.uvm.abt.edit.TestFrame");
			frame = (Frame)aFrameClass.newInstance();
		} catch (java.lang.Throwable ivjExc) {
			frame = new Frame();
		}
		Sign aSign;
		Class iiCls = Class.forName("Sign1");
		ClassLoader iiClsLoader = iiCls.getClassLoader();
		aSign = (Sign)java.beans.Beans.instantiate(iiClsLoader,"Sign");
		frame.add("Center", aSign);
		frame.setSize(aSign.getSize());
		frame.setVisible(true);
	} catch (Throwable exception) {
		System.err.println("Exception occurred in main() of java.applet.Applet");
		exception.printStackTrace(System.out);
	}
}
   // display the image in the Applet's Graphics context
   public void paint( Graphics g )
   {
		  
	  g.drawImage( buffer, intPos, 0, this );
	  	  	  
	  intPos = intPos - intStep;
	  intSecPos = intSecPos - intStep;
	  
	  if (intPos == 0 ) {
	  		intSecPos = intWidth;
	  }
	  else if (intSecPos == 0 ) {
			intPos = intWidth;
	  }
	  g.drawImage( buffer, intSecPos , 0, this );
	  
	  if (intPos < 0 - intWidth ) 
	  		intPos = intWidth;
	  else if (intSecPos < 0 - intWidth)
	  		intSecPos = intWidth;
	
   }                                                                                                                     
   public void run()
   {
	  
	  while (! stopSign ) {
		//--- mjk For the special case of only one image to display
		//    prevent array out of bounds
		 if ( currentImage >= myImage.length )
				currentImage = 0;
				
			
		 if ( imageTracker.checkID( currentImage, true ) ) {
			//--- clear previous image from buffer
			gContext.fillRect( 0, 0, intWidth, intHeight );
		  
			//--- draw new image in buffer
			gContext.drawImage(
			   myImage[ currentImage ], 0, 0, this );
   
			currentImage = ( currentImage + 1 ) % totalImages;
			
		 }

		 try {
			Thread.sleep( sleepTime );
		 }
		 catch ( InterruptedException e ) {
			showStatus( e.toString() );
		 }

		 repaint();  // display buffered image
	  }
   }                                             
   // start the applet
   public void start()
   {
	  //--- always start with 1st image
	  gContext.drawImage( myImage[ 0 ], 0, 0, this );
	  currentImage = 1;

	  //--- create a new animation thread when user visits page
	  if ( animate == null ) {
		 animate = new Thread( this );
		 animate.start();
	  }
   }                  
   // terminate animation thread when user leaves page
   public void stop()
   {
	  if ( animate != null ) {
		 //animate.stop();  IBM Visual age uses JDK1.1.7, JDK 1.2 deprecates
		 //animate = null;
		 stopSign = true;
	  }
   }               
   // override update to eliminate flicker
   public void update( Graphics g ) { paint( g ); }            
}