JAVA - Point2D

 

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package testpane;

import java.awt.Dimension;

import java.awt.EventQueue;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.RenderingHints;

import java.awt.geom.Ellipse2D;

import java.awt.geom.GeneralPath;

import java.awt.geom.Point2D;

import javax.swing.JFrame;

import javax.swing.JPanel;

public class Test {

    public static void main(String[] args) {

        new Test();

    }

    public Test() {

        EventQueue.invokeLater(new Runnable() {

            @Override

            public void run() {

                JFrame frame = new JFrame();

                frame.add(new TestPane());

                frame.pack();

                frame.setLocationRelativeTo(null);

                frame.setVisible(true);

            }

        });

    }

    public class TestPane extends JPanel {

        private GeneralPath gp = new GeneralPath();

        public TestPane() {

            //GeneralPath gp = new GeneralPath();

            gp.append(new Ellipse2D.Double(0, 0, 200, 200), true);

            for (double angle = 0; angle < 180; angle += 30) {

                Point2D startPoint = pointOnCircle(angle, 100);

                Point2D endPoint = pointOnCircle(angle + 180, 100);

                gp.moveTo(startPoint.getX(), startPoint.getY());

                gp.lineTo(endPoint.getX(), endPoint.getY());

            }

        }

        protected Point2D pointOnCircle(double degrees, double radius) {

            double origin = radius;

            double rads = Math.toRadians(degrees);

            double x = origin + (Math.cos(rads) * radius);

            double y = origin + (Math.sin(rads) * radius);

            return new Point2D.Double(x, y);

        }

        @Override

        public Dimension getPreferredSize() {

            return new Dimension(300, 300);

        }

        @Override

        protected void paintComponent(Graphics g) {

            super.paintComponent(g);

            Graphics2D g2d = (Graphics2D) g.create();

            RenderingHints hints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

            g2d.setRenderingHints(hints);

            g2d.translate(50, 50);

            g2d.draw(gp);

            g2d.dispose();

        }

    }

}