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package test;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
/** Displays a radar.
*/
public class RadarComponent extends JComponent {
/** Default width.
*/
public static int DEFAULT_WIDTH = 800;
/** Default height.
*/
public static int DEFAULT_HEIGHT = 800;
/** Back base paint.
* @todo Make this a configurable property.
*/
private static final Color BACK_RADAR_PAINT = Color.BLACK;
/** Front base paint.
* @todo Make this a configurable property.
*/
private static final Color FRONT_RADAR_PAINT = Color.GREEN;
/** Paint of the passive area.
* @todo Make this a configurable property.
*/
private static final Color FRONT_PASSIVE_RADAR_PAINT = FRONT_RADAR_PAINT.darker().darker();
/** Paint of the active line.
* @todo Make this a configurable property.
*/
private static final Color FRONT_ACTIVE_RADAR_PAINT = FRONT_RADAR_PAINT;
/** Paint of the echo area.
* @todo Make this a configurable property.
*/
private static final Color FRONT_ACTIVE_RADAR_TRANSPARENT_PAINT = new Color(FRONT_RADAR_PAINT.getRed(), FRONT_RADAR_PAINT.getGreen(), FRONT_RADAR_PAINT.getBlue(), 0);
/** Stroke of the passive line.
* @todo Make this a configurable property.
*/
private static final Stroke PASSIVE_STROKE = new BasicStroke(0.8f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL);
/** Stroke of the active line.
* @todo Make this a configurable property.
*/
private static final Stroke ACTIVE_STROKE = new BasicStroke(3f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL);
/** Default sleep time.
* @todo Make this a configurable property.
*/
private int SLEEP_TIME = 16;
/** Listener for timer events and component resizing events.
*/
private InnerListener innerListener = new InnerListener();
/** Timer for display refresh.
*/
private Timer timer = new Timer(SLEEP_TIME, innerListener);
/** Re-usable line.
*/
private Line2D.Float line = new Line2D.Float();
/** Re-usable pie slice shape.
*/
private Arc2D.Float arc = new Arc2D.Float();
private Rectangle2D arcRect = new Rectangle2D.Float();
/** Re-usable circular frame.
*/
private Ellipse2D.Float ellipse = new Ellipse2D.Float();
/** Current paint for the echo area.
*/
private GradientPaint gradient;
/** Current radius in pixels.
*/
private float radius;
/** Current diameter in pixels.
*/
private float diameter;
/** Current X coordinate of the center in pixels.
*/
private float centerX;
/** Current Y coordinate of the center in pixels.
*/
private float centerY;
/** Current X coordinate of the top left corner of the radar area in pixels.
*/
private float radarX;
/** Current Y coordinate of the top left corner of the radar area in pixels.
*/
private float radarY;
/** Current angle in radians.
*/
double angle = 0;
/** Angle offset in radians.
* @todo Make this a configurable property.
*/
double da = 2 * Math.PI / 1000;
/** Creates a new instance.
*/
public RadarComponent() {
super();
setPreferredSize(new Dimension(DEFAULT_WIDTH, DEFAULT_WIDTH));
precalculate();
addComponentListener(innerListener);
timer.start();
}
/** Precalculates and sets all necessary measures and objects.
*/
private void precalculate() {
int width = getWidth();
int height = getHeight();
radius = Math.min(width, height) / 2f;
if (radius != 0) {
diameter = 2 * radius;
centerX = width / 2f;
centerY = height / 2f;
radarX = centerX - radius;
radarY = centerY - radius;
// Note arc intialization angles are in degrees.
arc.setArc(new Rectangle2D.Double(radarX, radarY, diameter, diameter), 0f, 20f, Arc2D.PIE);
arcRect.setRect(centerX, centerY - radius / 8f, radius, radius / 8f);
// Rescale gradient accordingly.
// Note : this is a "should look OK" approximation. Could be better.
gradient = new GradientPaint(centerX, centerY - radius / 8f, FRONT_ACTIVE_RADAR_TRANSPARENT_PAINT, centerX, centerY, FRONT_RADAR_PAINT, false);
}
}
/** {@inheritDoc}
*/
@Override protected void paintComponent(Graphics g) {
super.paintComponent(g);
if ((radius > 0) && isVisible() && isShowing()) {
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
// Paint back circle.
g2d.setPaint(BACK_RADAR_PAINT);
ellipse.setFrame(radarX, radarY, diameter, diameter);
g2d.fill(ellipse);
// Paint axes.
g2d.setStroke(PASSIVE_STROKE);
g2d.setPaint(FRONT_PASSIVE_RADAR_PAINT);
float dx = radius / 4f;
for (int i = 0; i < 5; i++) {
ellipse.setFrame(radarX + i * dx, radarY + i * dx, diameter - 2 * i * dx, diameter - 2 * i * dx);
g2d.draw(ellipse);
}
line.setLine(radarX, centerY, radarX + diameter, centerY);
g2d.draw(line);
line.setLine(centerX, radarY, centerX, radarY + diameter);
g2d.draw(line);
// Backup current transformation.
AffineTransform backTransform = g2d.getTransform();
// Rotate to proper angle.
g2d.rotate(angle, centerX, centerY);
//Paint echo zone.
g2d.setPaint(gradient);
g2d.fill(arc);
//g2d.fill(arcRect);
// Paint active line.
g2d.setStroke(ACTIVE_STROKE);
g2d.setPaint(FRONT_ACTIVE_RADAR_PAINT);
line.setLine(centerX, centerY, centerX + radius, centerY);
g2d.draw(line);
//g2d.rotate(-angle, centerX, centerY);
// Restore transformation, avoid possible rounding error.
g2d.setTransform(backTransform);
}
}
/** Program entry point.
* @param args Arguments from the command line.
*/
public static void main(String ...args) {
Runnable runnable = new Runnable() {
/** {@inheritDoc}
*/
public void run() {
JFrame myFrame = new JFrame("A radar");
myFrame.add(new RadarComponent());
myFrame.pack();
//myFrame.setResizable(false);
myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
myFrame.setVisible(true);
}
};
SwingUtilities.invokeLater(runnable);
}
/** Inner listener for this component
*/
private class InnerListener implements ActionListener, ComponentListener {
/** Creates a new instanc.
*/
public InnerListener() {
}
/** {@inheritDoc}
* <br>Reacts to timer events.
*/
public void actionPerformed(ActionEvent event) {
angle += da;
if (isVisible() && (isShowing())) {
repaint();
}
}
/** {@inheritDoc}
* <br>Rescale graphical objects according to new size.
*/
public void componentResized(ComponentEvent event) {
precalculate();
if (isVisible() && (isShowing())) {
repaint();
}
}
/** {@inheritDoc}
*/
public void componentMoved(ComponentEvent event) {
}
/** {@inheritDoc}
*/
public void componentShown(ComponentEvent event) {
}
/** {@inheritDoc}
*/
public void componentHidden(ComponentEvent e) {
}
}
} |
