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Dial.javaAPI DocExample3735Sat Apr 23 22:35:42 BST 2005magicbeans

Dial

public class Dial extends JComponent

Fields Summary
int
minValue
int
nvalue
int
maxValue
int
radius
Constructors Summary
public Dial()

 this(0, 100, 0);
public Dial(int minValue, int maxValue, int value)

    setMinimum( minValue );
    setMaximum( maxValue );
    setValue( value );
    setForeground( Color.lightGray );

    addMouseListener(new MouseAdapter() {
      public void mousePressed(MouseEvent e) { spin(e); }
    });
    addMouseMotionListener(new MouseMotionAdapter() {
      public void mouseDragged(MouseEvent e) { spin(e); }
    });
Methods Summary
public voidaddDialListener(DialListener listener)

    listenerList.add( DialListener.class, listener );
private voiddraw3DCircle(java.awt.Graphics g, int x, int y, int radius, boolean raised)

    Color foreground = getForeground();
    Color light = foreground.brighter();
    Color dark = foreground.darker();
    g.setColor(foreground);
    g.fillOval(x, y, radius * 2, radius * 2);
    g.setColor(raised ? light : dark);
    g.drawArc(x, y, radius * 2, radius * 2, 45, 180);
    g.setColor(raised ? dark : light);
    g.drawArc(x, y, radius * 2, radius * 2, 225, 180);
voidfireEvent()

    for ( DialListener listener : getListeners( DialListener.class) )
        listener.dialAdjusted( new DialEvent(this, getValue()) );
public intgetMaximum()

 return maxValue;
public intgetMinimum()

 return minValue;
public java.awt.DimensiongetPreferredSize()

    return new Dimension(100, 100);
public intgetValue()

 return nvalue+minValue;
public static voidmain(java.lang.String[] args)

    JFrame frame = new JFrame("Dial v1.0");
    final JLabel statusLabel = new JLabel("Welcome to Dial v1.0");
    final Dial dial = new Dial();
    frame.getContentPane().add(dial, BorderLayout.CENTER);
    frame.getContentPane().add(statusLabel, BorderLayout.SOUTH);

    dial.addDialListener(new DialListener() {
      public void dialAdjusted(DialEvent e) {
        statusLabel.setText("Value is " + e.getValue());
      }
    });

    frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    frame.setSize( 150, 150 );
    frame.setVisible( true );
public voidpaintComponent(java.awt.Graphics g)

    Graphics2D g2 = (Graphics2D)g;
    int tick = 10;
    radius = Math.min( getSize().width,getSize().height )/2 - tick;
    g2.setPaint( getForeground().darker() );
    g2.drawLine( radius * 2 + tick / 2, radius, 
       radius * 2 + tick, radius);
    g2.setStroke( new BasicStroke(2) );
    draw3DCircle( g2, 0, 0, radius, true );
    int knobRadius = radius / 7;
    double th = nvalue * (2 * Math.PI) / (maxValue - minValue);
    int x = (int)(Math.cos(th) * (radius - knobRadius * 3)),
    y = (int)(Math.sin(th) * (radius - knobRadius * 3));
    g2.setStroke(new BasicStroke(1));
    draw3DCircle(g2, x + radius - knobRadius, 
       y + radius - knobRadius, knobRadius, false );
public voidremoveDialListener(DialListener listener)

    listenerList.remove( DialListener.class, listener );
public voidsetMaximum(int maxValue)

 this.maxValue = maxValue;
public voidsetMinimum(int minValue)

 this.minValue = minValue;
public voidsetValue(int value)

    this.nvalue = value - minValue;
    repaint();
    fireEvent();
protected voidspin(java.awt.event.MouseEvent e)

    int y = e.getY();
    int x = e.getX();
    double th = Math.atan((1.0 * y - radius) / (x - radius));
    int value=(int)(th / (2 * Math.PI) * (maxValue - minValue));
    if (x < radius)
      setValue( value + (maxValue-minValue) / 2 + minValue);
    else if (y < radius)
      setValue( value + maxValue );
    else
      setValue( value + minValue);