import java.awt.*;import javax.swing.*;import java.awt.event.*;import java.applet.Applet;import java.awt.geom.*;import java.awt.image.BufferedImage;public class Cubic extends JApplet{    static protected JLabel label;    CubicPanel cubicPanel;    public void init(){	//Initialize the layout.        getContentPane().setLayout(new BorderLayout());        cubicPanel = new CubicPanel();        cubicPanel.setBackground(Color.white);	getContentPane().add(cubicPanel);	label = new JLabel("Drag the points to adjust the curve.");	getContentPane().add("South", label);    }    public static void main(String s[]) {        JFrame f = new JFrame("Cubic");        CubicPanel cubicPanel = new CubicPanel();        f.addWindowListener(new WindowAdapter() {            public void windowClosing(WindowEvent e) {System.exit(0);}        });        JApplet applet = new Cubic();        f.getContentPane().add(applet, BorderLayout.CENTER);        applet.init();        f.setSize(new Dimension(350,250));        f.setVisible(true);    }}class CubicPanel extends JPanel implements MouseListener, MouseMotionListener{	BufferedImage bi;	Graphics2D big;	int x, y;	Rectangle area, startpt, endpt, ctrl1, ctrl2, rect;		CubicCurve2D.Double cubic = new CubicCurve2D.Double();	Point2D.Double start, end, one, two, point;	boolean firstTime = true;	boolean pressOut = false;	public CubicPanel(){		setBackground(Color.white);                addMouseMotionListener(this);                addMouseListener(this);		start = new Point2D.Double();		one = new Point2D.Double();		two = new Point2D.Double();		end = new Point2D.Double();                cubic.setCurve(start, one, two, end);		startpt = new Rectangle(0, 0, 8, 8);		endpt = new Rectangle(0, 0, 8, 8);		ctrl1 = new Rectangle(0, 0, 8, 8);		ctrl2 = new Rectangle(0, 0, 8, 8);	}	public void mousePressed(MouseEvent e){		x = e.getX();		y = e.getY();		if(startpt.contains(x, y)){			rect = startpt;			point = start;                        x = startpt.x - e.getX();                        y = startpt.y - e.getY();                        updateLocation(e);		} 		else if(endpt.contains(x, y)){			rect = endpt;			point = end;                        x = endpt.x - e.getX();                        y = endpt.y - e.getY();                        updateLocation(e);		}		else if(ctrl1.contains(x, y)){			rect = ctrl1;			point = one;                        x = ctrl1.x - e.getX();                        y = ctrl1.y - e.getY();                        updateLocation(e);		}		else if(ctrl2.contains(x, y)){			rect = ctrl2;			point = two;                        x = ctrl2.x - e.getX();                          y = ctrl2.y - e.getY();                        updateLocation(e);		} else {			pressOut = true;                }	}	public void mouseDragged(MouseEvent e){                if(!pressOut) {                        updateLocation(e);		}	}	public void mouseReleased(MouseEvent e){                if(startpt.contains(e.getX(), e.getY())){                        rect = startpt;                        point = start;                        updateLocation(e);                }                else if(endpt.contains(e.getX(), e.getY())){                        rect = endpt;                        point = end;                        updateLocation(e);                }                else if(ctrl1.contains(e.getX(), e.getY())){                        rect = ctrl1;                          point = one;                          updateLocation(e);                }                else if(ctrl2.contains(e.getX(), e.getY())){                        rect = ctrl2;                        point = two;                        updateLocation(e);                }                else {                        pressOut = false;                }	}	public void mouseMoved(MouseEvent e){}	public void mouseClicked(MouseEvent e){}	public void mouseExited(MouseEvent e){}	public void mouseEntered(MouseEvent e){}	public void updateLocation(MouseEvent e){		rect.setLocation((x + e.getX())-4, (y + e.getY())-4);		point.setLocation(x + e.getX(), y + e.getY());                checkPoint();                		cubic.setCurve(start, one, two, end);		repaint();	}	public void paintComponent(Graphics g){                super.paintComponent(g);		update(g);	}	public void update(Graphics g){		Graphics2D g2 = (Graphics2D)g;		Dimension dim = getSize();		int w = dim.width;                int h = dim.height;                            	if(firstTime){		  bi = (BufferedImage)createImage(w, h);		  big = bi.createGraphics();		  start.setLocation(w/2-50, h/2);		  end.setLocation(w/2+50, h/2);		  one.setLocation((int)(start.x)+25, (int)(start.y)-25);		  two.setLocation((int)(end.x)-25, (int)(end.y)+25);		  startpt.setLocation((int)((start.x)-4), (int)((start.y)-4));                  endpt.setLocation((int)((end.x)-4), (int)((end.y)-4));                  ctrl1.setLocation((int)((one.x)-4), (int)((one.y)-4));                  ctrl2.setLocation((int)((two.x)-4), (int)((two.y)-4));		  cubic.setCurve(start, one, two, end);        	  big.setColor(Color.black);		  big.setStroke(new BasicStroke(5.0f));		  big.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);		  area = new Rectangle(dim);		  firstTime = false;		} 		// Clears the rectangle that was previously drawn.		big.setColor(Color.white);		big.clearRect(0, 0, area.width, area.height);		// Draws and fills the newly positioned rectangle to the buffer.		big.setPaint(Color.black);		big.draw(cubic);		big.setPaint(Color.red);		big.fill(startpt);		big.setPaint(Color.magenta);		big.fill(endpt);		big.setPaint(Color.blue);		big.fill(ctrl1);		big.setPaint(new Color(0, 200, 0));		big.fill(ctrl2);		// Draws the buffered image to the screen.		g2.drawImage(bi, 0, 0, this);	}	/*         * Checks if the rectangle is contained within the applet window.  If the rectangle         * is not contained withing the applet window, it is redrawn so that it is adjacent         * to the edge of the window and just inside the window.	 */	void checkPoint(){				if (area == null) {			return;		}		if((area.contains(rect)) && (area.contains(point))){			return;		}		int new_x = rect.x;		int new_y = rect.y;		double new_px = point.x;		double new_py = point.y;		if((rect.x+rect.width)>area.getWidth()){			new_x = (int)area.getWidth()-(rect.width-1);		}		if(point.x > area.getWidth()){			new_px = (int)area.getWidth()-1;		}		if(rect.x < 0){  			new_x = -1;		}		if(point.x < 0){			new_px = -1;		}		if((rect.y+rect.width)>area.getHeight()){			new_y = (int)area.getHeight()-(rect.height-1);		}		if(point.y > area.getHeight()){			new_py = (int)area.getHeight()-1;		}		if(rect.y < 0){  			new_y = -1;		}		if(point.y < 0){                        new_py = -1;                }		rect.setLocation(new_x, new_y);		point.setLocation(new_px, new_py);	}}