package cn.ksource.test;
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import java.awt.Color;
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import java.awt.GradientPaint;
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import java.awt.Graphics;
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import java.awt.Graphics2D;
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import java.awt.Paint;
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import java.awt.Point;
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import java.awt.RadialGradientPaint;
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import java.awt.RenderingHints;
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import java.awt.Shape;
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import java.awt.event.KeyAdapter;
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import java.awt.event.KeyEvent;
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import java.awt.event.MouseAdapter;
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import java.awt.event.MouseEvent;
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import java.awt.geom.GeneralPath;
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import java.awt.geom.Point2D;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.Random;
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import java.util.Set;
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import javax.swing.JFrame;
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import javax.swing.JPanel;
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import javax.swing.SwingUtilities;
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@SuppressWarnings("serial")
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public class Star extends JPanel {
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private Map<Shape, Point> stars = new HashMap<Shape, Point>();
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private Random rand = new Random(System.currentTimeMillis());
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public Star() {
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this.stars.put(createStar(5, 10, 15), new Point(40, 40));
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this.setFocusable(true);
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this.addMouseListener(new MouseAdapter() {
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@Override
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public void mousePressed(MouseEvent e) {
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int count = 2 + rand.nextInt(15);
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double innerRadius = 5 + rand.nextInt(20);
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double outerRadius = innerRadius + 10 + rand.nextInt(30);
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GeneralPath s = createStar(count, innerRadius, outerRadius);
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stars.put(s, new Point(e.getX(), e.getY()));
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repaint();
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}
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});
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this.addKeyListener(new KeyAdapter() {
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@Override
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public void keyReleased(KeyEvent e) {
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if (e.getKeyCode() == KeyEvent.VK_R) {
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stars.clear();
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repaint();
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}
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}
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});
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}
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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Graphics2D g2d = (Graphics2D) g;
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g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
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// Paint a gradient for the sky
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GradientPaint background = new GradientPaint(0f, 0f, Color.GRAY.darker(), 0f, getHeight(),
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Color.GRAY.brighter());
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g2d.setPaint(background);
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g2d.fillRect(0, 0, getWidth(), 4 * getHeight() / 5);
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// Paint a gradient for the ground
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background = new GradientPaint(0f, 4 * getHeight() / 5, Color.BLACK, 0f, getHeight(),
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Color.GRAY.darker());
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g2d.setPaint(background);
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g2d.fillRect(0, 4 * getHeight() / 5, getWidth(), getHeight() / 5 + 4);
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// Using a radial gradient paint
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float[] fractions = new float[] { 0.0f, 0.40f };
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Color[] colors = new Color[] { Color.WHITE, new Color(0.0f, 0.0f, 0.0f, 0.5f) };
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Paint p = new RadialGradientPaint(0, 0, 100, fractions, colors);
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g2d.setPaint(p);
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// Show the stars
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Set<Map.Entry<Shape, Point>> items = stars.entrySet();
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for (Map.Entry<Shape, Point> s : items) {
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g2d.translate(s.getValue().getX(), s.getValue().getY());
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g2d.fill(s.getKey());
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g2d.translate(-s.getValue().getX(), -s.getValue().getY());
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}
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}
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// 创建一个星形路径
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public static GeneralPath createStar(int count, double innerRadius, double outerRadius) {
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// 因为swing中缀坐标向下，所以正上方的中点坐标是负值
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GeneralPath star = new GeneralPath();
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double extentAngle = 360.0 / count;
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Point2D op = new Point2D.Double(0, -outerRadius);
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Point2D ip = GeometryUtil.rotate(0, -innerRadius, extentAngle / 2);
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star.moveTo(op.getX(), op.getY());
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star.lineTo(ip.getX(), ip.getY());
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for (int i = 0; i < count - 1; ++i) {
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op = GeometryUtil.rotate(op.getX(), op.getY(), extentAngle);
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star.lineTo(op.getX(), op.getY());
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ip = GeometryUtil.rotate(ip.getX(), ip.getY(), extentAngle);
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star.lineTo(ip.getX(), ip.getY());
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}
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star.closePath();
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return star;
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}
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private static void createGuiAndShow() {
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JFrame frame = new JFrame("Star");
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frame.getContentPane().add(new Star());
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frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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frame.setSize(550, 400);
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frame.setAlwaysOnTop(true);
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frame.setLocationRelativeTo(null);
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frame.setVisible(true);
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}
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public static void main(String[] args) {
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SwingUtilities.invokeLater(new Runnable() {
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@Override
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public void run() {
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createGuiAndShow();
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}
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});
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}
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}
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