j_flower.java

一个十分好的java基础学习的课件

// ////////////////////////////////////////////////////////
// 
// J_Flower.java
// 

// ////////////////////////////////////////////////////////

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
import javax.swing.*;


public class J_Flower extends JApplet implements ActionListener
{

    int     m_frame = -1;     // The number of the current frame in the animation.
    Timer   m_timer;          // The timer controlling the animation.
    boolean m_frozen = false; // Status of stopping animation.
    boolean m_ready = true;  // Status of the next frame is ready.
    BufferedImage m_image= new BufferedImage(320, 320, BufferedImage.TYPE_INT_RGB );

    public void init( )
    {
        int delay = 25;
        mb_draw( );
        m_timer = new Timer(delay, this);
        m_timer.setInitialDelay(0);
        m_timer.setCoalesce(true);

        getContentPane( ).addMouseListener(new MouseAdapter( )
        {
            public void mousePressed(MouseEvent e)
            {
                m_frozen = !m_frozen;
                if (m_frozen)
                     mb_stopAnimation( );
                else mb_startAnimation( );
            }
        });
    } // End of method: init

    public void start( )
    { 
        mb_startAnimation( );
    } // End of method: start

    public void stop( )
    { 
        mb_stopAnimation( );
    } // End of method: stop

    public void actionPerformed(ActionEvent e)
    {
        m_frame++; //Advance the animation frame.
        //Request that the frame be painted.
        repaint( );
    } // End of method: actionPerformed

    public synchronized void mb_startAnimation( )
    {
        if (!m_frozen && !m_timer.isRunning( ))
            m_timer.start( );
    } // End of method: mb_startAnimation

    public synchronized void mb_stopAnimation( )
    {
        if (m_timer.isRunning( ))
            m_timer.stop( );
    } // End of method: mb_stopAnimation

    public void mb_draw( )
    {
        if (!m_ready)
            return;
        m_ready=false;
        Graphics2D g2d = m_image.createGraphics( );
        int i= (m_frame>0 ? m_frame%600 : (-m_frame)%600);
        double a= (i>300 ? 600-i : i);
        double b= a*6/16;
        double a_2= a/2;
        double b_2= b/2;
        
        // Draw grass
        g2d.setPaint(new GradientPaint(0, 0, new Color(187,255,204), 0,300, Color.green, true));
        g2d.fill( new Rectangle2D.Double( 0, 0, 320,  300));

        // Draw flower
        g2d.setColor( Color.magenta );
        g2d.fill( new Ellipse2D.Double( 160-b_2, 150-a_2, b, a));
        g2d.fill( new Ellipse2D.Double( 160-a_2, 150-b_2, a, b ));		
        g2d.setColor( Color.orange );
        g2d.fill( new Ellipse2D.Double( 160-b_2, 150-b_2, b, b ));

        // Draw Frame number
        g2d.setPaint(Color.white);
        g2d.fill( new Rectangle2D.Double( 0, 300, 320, 20 ) );
        g2d.setColor(Color.black);
        g2d.drawString(""+m_frame, 150, 315);
        m_ready=true;
    } // End of method: mb_draw 

    public void paint(Graphics g)
    {
        if (m_ready)
            g.drawImage(m_image, 0, 0, 320, 320, this);
        mb_draw( );
    } // End of method: paint

} // End of class: J_Flower