Programming Languages Suite/ProgLangD.iso/Java++/VJ/SAMPLES/JAVANOW/CHAP16/ANIMATIONMT/ANIMATIONMT.JAVA

Java Source | 1996-07-02 | 4.7 KB | 184 lines

// AnimationMT - this version of Animation uses the MediaTracker
//               to monitor the progress of loading the images
import java.applet.*;
import java.awt.*;

public class AnimationMT extends Applet implements Runnable
{
    Thread     m_AnimationMT = null;

    private int m_fps = 10;
    private String m_imageFile = "LJN";
    private int m_numImages = 22;

    // 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";

        // use a media tracker to monitor progress
    MediaTracker m_mediaTracker = new MediaTracker(this);

    // store frame information here
    int   m_nFrameNumber = 0;
    Image m_frame[];

    public AnimationMT()
    {
        // TODO: Add constructor code here
    }

    public String getAppletInfo()
    {
        return "Name: AnimationMT\r\n" +
               "Author: Stephen R. Davis\r\n" +
               "Created for Learn Java Now (c)";
    }

    public String[][] getParameterInfo()
    {
        String[][] info =
        {
            { PARAM_fps, "int", "Frame rate" },
            { PARAM_imageFile, "String", "Name of file seq" },
            { PARAM_numImages, "int", "Number of images" },
        };
        return info;
    }

    public void init()
    {
        String param;

        param = getParameter(PARAM_fps);
        if (param != null)
            m_fps = Integer.parseInt(param);

        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(320, 240);

        // TODO: Place additional initialization code here
        // Load images
        m_frame = new Image[m_numImages];
        String sImageFile;
        int nImageNum;
        for (int i = 0; i < m_numImages; i++)
        {
            nImageNum = i + 1;
            sImageFile = m_imageFile +
                         ((nImageNum < 10)?"0":"") +
                         nImageNum +
                         ".gif";
            m_frame[i] = getImage(getDocumentBase(), sImageFile);

            // add this frame to the media tracker
            m_mediaTracker.addImage(m_frame[i], 0);
        }
    }

    public void destroy()
    {
        // TODO: Place applet cleanup code here
    }

    public void paint(Graphics g)
    {
        if (m_mediaTracker.checkAll())
        {
           // if there was an error...
           if (m_mediaTracker.isErrorAny())
           {
               // ...signal the error
               g.drawString("Error loading an image", 10, 20);
               return;
           }

           // draw the current frame
           g.drawImage(m_frame[m_nFrameNumber], 0, 0, null);

           // update the frame number
           m_nFrameNumber++;
           if (m_nFrameNumber >= m_numImages)
           {
               m_nFrameNumber = 0;
           }
        }
        else
        {
            g.drawString("Loading images...", 10, 20);
        }
    }

    public void update(Graphics g)
    {
        paint(g);
    }

    public void start()
    {
        if (m_AnimationMT == null)
        {
            m_AnimationMT = new Thread(this);
            m_AnimationMT.start();
        }
        // TODO: Place additional applet start code here
    }

    public void stop()
    {
        if (m_AnimationMT != null)
        {
            m_AnimationMT.stop();
            m_AnimationMT = null;
        }

        // TODO: Place additional applet stop code here
    }

    public void run()
    {
        try
        {
            // set the frame number to zero
            m_nFrameNumber = 0;

            // force a repaint
            repaint();

            // now force the images to be loaded
            m_mediaTracker.waitForAll();

            // resize the screen to match the images
            resize(m_frame[0].getWidth(null),
                   m_frame[0].getHeight(null));

            // calculate delay time based on frame rate
            int nDelay = 1000 / m_fps;
            while (true)
            {
                repaint();
                Thread.sleep(nDelay);
            }
        }
        catch (InterruptedException e)
        {
            stop();
        }
    }
}