//******************************************************************************
// anim4gifs.java:	Applet
//
//******************************************************************************
import java.applet.*;
import java.awt.*;

//==============================================================================
// Main Class for applet anim4gifs
//
//==============================================================================
public class anim4gifs extends Applet implements Runnable
{
	// THREAD SUPPORT:
	//		m_anim4gifs	is the Thread object for the applet
	//--------------------------------------------------------------------------
	Thread	 m_anim4gifs = null;

	// ANIMATION SUPPORT:
	//		m_Graphics		used for storing the applet's Graphics context
	//		m_Images[]		the array of Image objects for the animation
	//		m_nCurrImage	the index of the next image to be displayed
	//		m_ImgWidth		width of each image
	//		m_ImgHeight		height of each image
	//		m_fAllLoaded	indicates whether all images have been loaded
	//--------------------------------------------------------------------------
	private Graphics m_Graphics;
	private Image	 m_Images[];
	private int 	 m_nCurrImage;
	private int 	 m_nImgWidth  = 0;
	private int 	 m_nImgHeight = 0;
	private boolean  m_fAllLoaded = false;

	// PARAMETER SUPPORT:
	//		Parameters allow an HTML author to pass information to the applet;
	// the HTML author specifies them using the <PARAM> tag within the <APPLET>
	// tag.  The following variables are used to store the values of the
	// parameters.
    //--------------------------------------------------------------------------

    // Members for applet parameters
    // <type>       <MemberVar>    = <Default Value>
    //--------------------------------------------------------------------------
	private int m_fps = 15;
	private String m_imageFile = "anim";
	private int m_numImages = 15;

	private int m_nSleepTime;	 // based on m_fps
    // Parameter names.  To change a name of a parameter, you need only make
	// a single change.  Simply modify the value of the parameter string below.
    //--------------------------------------------------------------------------
	private final String PARAM_fps = "fps";
	private final String PARAM_imageFile = "imageFile";
	private final String PARAM_numImages = "numImages";

	// anim4gifs Class Constructor
	//--------------------------------------------------------------------------
	public anim4gifs()
	{
		// TODO: Add constructor code here
	}

	// APPLET INFO SUPPORT:
	//		The getAppletInfo() method returns a string describing the applet's
	// author, copyright date, or miscellaneous information.
    //--------------------------------------------------------------------------
	public String getAppletInfo()
	{
		return "Name: anim4gifs\r\n" +
		       "Author: Zoran Lazarevic\r\n" +
		       "Example from \"Learn Java Now\"";
	}

	// PARAMETER SUPPORT
	//		The getParameterInfo() method returns an array of strings describing
	// the parameters understood by this applet.
	//
    // anim4gifs Parameter Information:
    //  { "Name", "Type", "Description" },
    //--------------------------------------------------------------------------
	public String[][] getParameterInfo()
	{
		String[][] info =
		{
			{ PARAM_fps, "int", "Frames per second" },
			{ PARAM_imageFile, "String", "Filename of the mage" },
			{ PARAM_numImages, "int", "Number of images" },
		};
		return info;		
	}

	// The init() method is called by the AWT when an applet is first loaded or
	// reloaded.  Override this method to perform whatever initialization your
	// applet needs, such as initializing data structures, loading images or
	// fonts, creating frame windows, setting the layout manager, or adding UI
	// components.
    //--------------------------------------------------------------------------
	public void init()
	{
		// PARAMETER SUPPORT
		//		The following code retrieves the value of each parameter
		// specified with the <PARAM> tag and stores it in a member
		// variable.
		//----------------------------------------------------------------------
		String param;

		// PARAM_fps: Frames per second
		//----------------------------------------------------------------------
		param = getParameter(PARAM_fps);
		if (param != null)
			m_fps = Integer.parseInt(param);

		// PARAM_imageFile: Filename of the mage
		//----------------------------------------------------------------------
		param = getParameter(PARAM_imageFile);
		if (param != null)
			m_imageFile = param;

		param = getParameter(PARAM_numImages);
		if (param != null)
			m_numImages = Integer.parseInt(param);

        // If you use a ResourceWizard-generated "control creator" class to
        // arrange controls in your applet, you may want to call its
        // CreateControls() method from within this method. Remove the following
        // call to resize() before adding the call to CreateControls();
        // CreateControls() does its own resizing.
        //----------------------------------------------------------------------
		resize(size().width, size().height);

		// TODO: Place additional initialization code here
		// Calculate sleep time
		if (m_fps != 0) {
			m_nSleepTime = 1000/m_fps;
		}
	}

	// Place additional applet clean up code here.  destroy() is called when
	// when you applet is terminating and being unloaded.
	//-------------------------------------------------------------------------
	public void destroy()
	{
		// TODO: Place applet cleanup code here
	}

    // ANIMATION SUPPORT:
    //		Draws the next image, if all images are currently loaded
    //--------------------------------------------------------------------------
	private void displayImage(Graphics g)
	{
		if (!m_fAllLoaded)
			return;

		// Draw Image in center of applet
		//----------------------------------------------------------------------
		g.drawImage(m_Images[m_nCurrImage],
				   (size().width - m_nImgWidth)   / 2,
				   (size().height - m_nImgHeight) / 2, null);
	}

	// anim4gifs Paint Handler
	//--------------------------------------------------------------------------
	public void paint(Graphics g)
	{
		// ANIMATION SUPPORT:
		//		The following code displays a status message until all the
		// images are loaded. Then it calls displayImage to display the current
		// image.
		//----------------------------------------------------------------------
		if (m_fAllLoaded)
		{
			Rectangle r = g.getClipRect();
			
			g.clearRect(r.x, r.y, r.width, r.height);
			displayImage(g);
		}
		else
			g.drawString("Loading Images..."+m_imageFile, 10, 20);

		// TODO: Place additional applet Paint code here
	}

	//		The start() method is called when the page containing the applet
	// first appears on the screen. The AppletWizard's initial implementation
	// of this method starts execution of the applet's thread.
	//--------------------------------------------------------------------------
	public void start()
	{
		if (m_anim4gifs == null)
		{
			m_anim4gifs = new Thread(this);
			m_anim4gifs.start();
		}
		// TODO: Place additional applet start code here
	}
	
	//		The stop() method is called when the page containing the applet is
	// no longer on the screen. The AppletWizard's initial implementation of
	// this method stops execution of the applet's thread.
	//--------------------------------------------------------------------------
	public void stop()
	{
		if (m_anim4gifs != null)
		{
			m_anim4gifs.stop();
			m_anim4gifs = null;
		}

		// TODO: Place additional applet stop code here
	}

	// THREAD SUPPORT
	//		The run() method is called when the applet's thread is started. If
	// your applet performs any ongoing activities without waiting for user
	// input, the code for implementing that behavior typically goes here. For
	// example, for an applet that performs animation, the run() method controls
	// the display of images.
	//--------------------------------------------------------------------------
	public void run()
	{
		m_nCurrImage = 0;
		
		// If re-entering the page, then the images have already been loaded.
		// m_fAllLoaded == TRUE.
		//----------------------------------------------------------------------
        if (!m_fAllLoaded)
		{
    		repaint();
    		m_Graphics = getGraphics();
    		m_Images   = new Image[m_numImages];

    		// Load in all the images
    		//------------------------------------------------------------------
    		MediaTracker tracker = new MediaTracker(this);
    		String strImage;

    		// For each image in the animation, this method first constructs a
    		// string containing the path to the image file; then it begins
    		// loading the image into the m_Images array.  Note that the call to
    		// getImage will return before the image is completely loaded.
    		//------------------------------------------------------------------
			strImage = m_imageFile + "01" + ".gif";
			m_Images[0] = getImage(getDocumentBase(), strImage);

			Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
			tracker.addImage(m_Images[0], 1);
			try {	tracker.waitForAll(); } catch(InterruptedException e){}
			m_nCurrImage = 0;
			displayImage(m_Graphics);
			Thread.currentThread().setPriority(Thread.MIN_PRIORITY);

			for (int i = 1; i < m_numImages; i++)
    		{
    			// Build path to next image
    			//--------------------------------------------------------------
    			strImage = m_imageFile + ((i < 10) ? "0" : "") + i + ".gif";
			    m_Images[i] = getImage(getDocumentBase(), strImage);

                tracker.addImage(m_Images[i], 1);
    		}

    		// Wait until all images are fully loaded
    		//------------------------------------------------------------------
			try
			{
				tracker.waitForAll();
				m_fAllLoaded = !tracker.isErrorAny();
			}
			catch (InterruptedException e)
			{
				// TODO: Place exception-handling code here in case an
				//       InterruptedException is thrown by Thread.sleep(),
				//		 meaning that another thread has interrupted this one
			}
			
			if (!m_fAllLoaded)
			{
			    stop();
			    m_Graphics.drawString("Error loading images!", 10, 40);
			    return;
			}
			

			// Assuming all images are same width and height.
			//--------------------------------------------------------------
		    m_nImgWidth  = m_Images[0].getWidth(this);
		    m_nImgHeight = m_Images[0].getHeight(this);
        }		
		repaint();

		while (true)
		{
			try
			{
				// Draw next image in animation
				//--------------------------------------------------------------
				displayImage(m_Graphics);
				m_nCurrImage++;
				if (m_nCurrImage == m_numImages)
					m_nCurrImage = 0;

				// TODO:  Add additional thread-specific code here
				Thread.sleep(m_nSleepTime);
			}
			catch (InterruptedException e)
			{
				// TODO: Place exception-handling code here in case an
				//       InterruptedException is thrown by Thread.sleep(),
				//		 meaning that another thread has interrupted this one
				stop();
			}
		}
	}



	// TODO: Place additional applet code here

}