Java雷达扫描图

上图，上代码

package demo;import java.awt.AlphaComposite;import java.awt.Color;import java.awt.Composite;import java.awt.Dimension;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.geom.Arc2D;import java.awt.geom.Ellipse2D;import javax.swing.JComponent;import javax.swing.JFrame;import blade.paint.FanShapedGradientPaint;/** *  * @author Administrator *  */public class RadarDemo extends JComponent {public static void main(String argv[]) {JFrame frame = new JFrame();frame.setContentPane(new RadarDemo());frame.setSize(800, 600);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setVisible(true);}@Overridepublic void paintComponent(Graphics g) {Graphics2D g2d = (Graphics2D) g;g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);paintBackground(g);paintRadarRing(g);paintFanShapedGradient(g);}protected void paintBackground(Graphics g) {g.setColor(Color.black);g.fillRect(0, 0, this.getWidth(), this.getHeight());}protected void paintRadarRing(Graphics g) {Graphics2D g2d = (Graphics2D) g;g.setColor(Color.green);Dimension d = this.getSize();double radius = Math.min(d.width, d.height) / 2;for (int r = 1; r <= 5; r++) {double R = r * radius / 5;double x = d.width / 2 - R;double y = d.height / 2 - R;Ellipse2D ellipse = new Ellipse2D.Double(x, y, R * 2, R * 2);g2d.draw(ellipse);}}protected void paintFanShapedGradient(Graphics g) {Graphics2D g2d = (Graphics2D) g;Composite oldComp = g2d.getComposite();AlphaComposite comp = AlphaComposite.getInstance(3, 0.5f);g2d.setComposite(comp);Dimension d = this.getSize();double radius = Math.min(d.width, d.height) / 2;double x = (d.width - radius * 2) / 2;double y = (d.height - radius * 2) / 2;FanShapedGradientPaint paint = new FanShapedGradientPaint(x, y, Math.PI / 2, Math.PI / 2, radius, Color.green,Color.black);g2d.setPaint(paint);Arc2D arc = new Arc2D.Double(x, y, radius * 2, radius * 2, 90, 90, Arc2D.PIE);g2d.fill(arc);g2d.setComposite(oldComp);}}