import java.applet.Applet;
import java.applet.*;
import java.awt.*;

public class scroll extends Applet implements Runnable {
	
	private Image image;
	private Graphics offscreen;
	private Thread runner;
	private boolean running;
	private Color background;
    	private Color foreground;
    	private Font f;
    	private FontMetrics fm;
    	private static final int maxLine=100;
    	private int lMargin=5;
    	private String lines[];
    	private String text;
    	private int whichLine=0;
    	private int maxSize;
    	private int maxWidth;
    	private int typeHeight;
    	private int typeLength;
    	private int typePos;
    	private int runningIndex=0;
    	private int arrayCount=0;
    	private int onScreenLines=0;
        private int where=0;
        private int offset=0;
        private int start=0;
        private int pointSize;
        private int speed;
			
        public void init() {
		background=Color.black;
		foreground=Color.gray;
		maxWidth=getSize().width;
        	maxSize=getSize().height;
        	
        	//create offscreen image
        	image=createImage(maxWidth,maxSize);
        	offscreen=image.getGraphics();
        	
        	//get applet parameters for scroll speed, point size & message
        	String s=getParameter("pointSize");
        	if (s==null) {
			pointSize=30;
		}
		else pointSize=Integer.parseInt(s);
		if (pointSize>30 || pointSize<=0) pointSize=30;
		String s2=getParameter("speed");
        	if (s2==null) {
			speed=80;
		}
		else speed=Integer.parseInt(s2);
		text=getParameter("text");
		if (text==null) text="No message.  ";
		
		maxWidth=getSize().width;
        	maxSize=getSize().height;
        	
        	//create offscreen image
        	image=createImage(maxWidth,maxSize);
        	offscreen=image.getGraphics();
        	
        	//create font & type 
        	f=new Font ("Helvetica",Font.BOLD,pointSize);
		fm=getFontMetrics (f);
        	typeHeight=fm.getHeight();
        	typePos=maxSize+typeHeight;
        	lines=new String[maxLine];
        	split();
        }
  
        public void update(Graphics g) {
    		paint(g);
   	}
  
   	public void paint(Graphics g) {
   		offscreen.setColor(background);
     		offscreen.fillRect(0,0,maxWidth,maxSize);
    		scroll();
    		g.drawImage(image,0,0,this);  		
      	}
    
    	public void destroy() {
    		offscreen.dispose();
        }
        
        public void start() {
        	if (runner==null) {
        		runner=new Thread(this);
        		runner.start();
        		running=true;
        	}
        }
        
        public void stop() {
        	running=false;
        }
        
        public void run() {
        	try {
            		while (running) {
            			runner.sleep(20);
            			repaint();
            		}
        	} 
        	catch(InterruptedException e) {
            	running = false;
            	}
        }
        
        public void split() {
        	//parse long text string into scrollable lines
        	int index=0;
        	int nextSpace=0;
        	int prevSpace=0;
        	String runningTotal="";
        	String testLength="";
        	if ((fm.stringWidth(text)+lMargin)>maxWidth) {
        		while (runningIndex<text.length()) {
        			nextSpace=text.indexOf(" ",runningIndex);
        			//MSIE kludge...**warning** poor programming practice ahead 
        			if (nextSpace<0) {
        				lines[arrayCount]=text.substring(index,text.length()).trim();
        				arrayCount++;
        				break;
        			}
        			testLength=text.substring(index,nextSpace);
        			if ((fm.stringWidth(testLength)+lMargin)>maxWidth || (nextSpace==text.length()-1)) {
        				lines[arrayCount]=runningTotal.trim();
        				arrayCount++;
        				runningTotal="";
        				index=prevSpace;        			
        			}
        			runningIndex=nextSpace+1;
        			runningTotal=testLength;
        			prevSpace=nextSpace;
        		}
              		lines[arrayCount]=runningTotal.trim();
              	}
              	else {
              		arrayCount=1;
              		lines[0]=text.trim();
              	}
              	arrayCount--;
        }
        
        public void scroll() {
        	offscreen.setColor(foreground);
   		offscreen.setFont(f);
   		//iteration count for display calc (start=array pointer)
   		int j=0;
   		for (int i=start;i<=onScreenLines;i++) {
   			offscreen.drawString(lines[i],lMargin,typePos+(j*typeHeight));
   			j++;
   		}
   		//position of lead line
   		typePos--;
   		//running total of scroll offset
   		offset++;
   		//offset=typeheight so bump array of text end pointer
   		if (offset==typeHeight) {
   			offset=0;
   			onScreenLines++;
   		}
   		if (onScreenLines>arrayCount) onScreenLines=arrayCount;
   		//message finished scroll so reset
   		if ((start==onScreenLines) && (typePos<(0-typeHeight))) {
   			start=0;
   			onScreenLines=0;
   			typePos=maxSize+typeHeight;
   		}
   		//line scrolled off top, so adjust array pointer
   		if (typePos<(0-typeHeight)) {
   			start++;
   			typePos=0;
   		}
   	}
}