an ammeter ( round gauge ) sortof widget built using Swing

Here's another widget I built using Swing. This one is a round gauge like an ammeter. I've set it up to function as a sort of progress meter but you can modify it to do whatever you want. There's two files to this eclipse project.



This is the first file:

java code

package lgfRoundGauge;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.*;

public class RoundGaugePanel extends JPanel implements Runnable {
	
	int targetValue = 0;
	int MAX_VALUE 	= 100; // default to 100 for now
	int value 		= 0;
	Thread repaintThread;
	int degreesPerSecond = 1;
	Dimension Size;
	double gaugeWidth;
	double gaugeHeight;
	int    centerX = (int)(gaugeWidth/2.0);
	int    centerY = (int)(gaugeHeight/2.0);
	double zeroAngle = 225.0;
	double maxAngle  = -45; 
	double range = zeroAngle - maxAngle;
	
	RoundGaugePanel(Dimension size) {
		Size = size;
		gaugeWidth 	= Size.width  * 0.75;
		gaugeHeight = Size.height * 0.75;
		centerX = (int)(gaugeWidth/2.0);
		centerY = (int)(gaugeHeight/2.0);
		setSize(Size);
		setMaximumSize(Size);
		setPreferredSize(Size);
		repaintThread = new Thread( this );
		repaintThread.setDaemon(true);
		repaintThread.start();
	}
	
	public void updateValue( int i ){ targetValue = i; }
	public void setMaxValue( int i) { MAX_VALUE = i; }
	
	private void paintTheBackground( Graphics g) {
		g.setColor(Color.black);
		g.fillRect(0, 0, Size.width, Size.height);
		g.setColor(Color.white);
		g.fillOval(0, 0, (int)gaugeWidth, (int)gaugeHeight);
		// now the lines and the arcs on the gauge
		g.setColor( Color.lightGray);
		g.drawLine(centerX, centerY, (int) gaugeWidth -25, (int)gaugeHeight-25);
		g.drawLine(centerX, centerY, 23, (int)gaugeHeight-25);
		g.setColor( Color.blue);
		g.drawArc( 10, 10, (int)gaugeWidth-20, (int)gaugeHeight-20, -45, 270);
		// yellow doesn't show up really well on a white background
		//g.setColor( Color.yellow);
		//g.drawArc( 10, 10, (int)gaugeWidth-20, (int)gaugeHeight-20, 0, 45);
		// this red line doesn't add much to the gauge so....
		//g.setColor( Color.red);
		//g.drawArc( 10, 10, (int)gaugeWidth-20, (int)gaugeHeight-20, -45, 45 );
		g.setColor( Color.black);
		g.drawString("0%", centerX - 45, centerY + 55);
		g.drawString("50%", centerX - 5, centerY - 50);
		g.drawString("100%", centerX + 15, centerY + 55);
		
	}	
	
	public void paintComponent(Graphics g){
		Color oldColor;
		oldColor = g.getColor();
		paintTheBackground( g);

		g.setColor(Color.red);
		int x1 = centerX, 	
		    x2 = x1, 
		    y1 = centerY, 	
		    y2 = y1;
		double angleToUse = zeroAngle - 1.0 * range *( value * 1.0 / MAX_VALUE * 1.0);
	    x2 += (int)( Math.cos(Math.toRadians(angleToUse))*centerX);
	    y2 -= (int)( Math.sin(Math.toRadians(angleToUse))*centerY);
		g.drawLine(x1, y1, x2, y2 );
		g.setColor(Color.black);
		g.drawString(""+ value, centerX - 10, centerY + 30);
		g.setColor(oldColor);
	}
	public void run() {
		int oldValue = 32768;
		while ( true ) {
			try {
				Thread.sleep(100);
			} catch( InterruptedException ie) { /**/ }
			
			if ( targetValue != value ) {
				if ( degreesPerSecond  value ) value += degreesPerSecond;
			}
			
			if( oldValue != value) {
				repaint();
				oldValue = value;
			}
		} // close while()
	} // close run()
} // close class RoundGaugePanel

Here's the second of two files:

java code

package lgfRoundGauge;

import java.awt.Dimension;
import javax.swing.JFrame;
/*
 *  this code started 15JUN2007 17:10 pm
 *  finished          15JUN2007 23:07 pm
 */
public class RoundGauge {

	RoundGaugePanel rp;
	Dimension size = new Dimension( 200, 200);
	
	public RoundGauge(){
		
		rp = new RoundGaugePanel( size );
		JFrame frame = new JFrame("RoundGaugePanel Test" );
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(size);
		frame.setMaximumSize(size);
		frame.setPreferredSize(size);
		frame.add(rp);
		frame.pack();
		frame.setVisible(true);
	}
	public void updateValue( int i) { rp.updateValue( i ); }
	public void setMaxValue( int i) { rp.setMaxValue(i); }
	public static void main(String[] args) {
		RoundGauge r = new RoundGauge();
		r.setMaxValue(10000);
		// I'm not messing with the event dispatch thread here 'cause
		// nothing touches the swing components at all....one of them
		// reads an interger variable I'm modifying but that's okay
		for( int i = 0; i < 99; i++) {
			try {
				r.updateValue(i * 100 );
				Thread.sleep(100);
			} catch(InterruptedException ie) {/**/}	
		}
	} // close main
} // close class RoundGauge

All this code is in the public domain so you can do with it whatever you'd like

Thanks , Very Cool one ,

Thanks for this good topic.

Thx!!!! Cool