Java Tutorial/2D Graphics/Graphic Path

Bezier Lab

import java.awt.Color;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.GeneralPath;
public class BezLab extends Frame implements MouseListener, MouseMotionListener {
  private int[] xs = { 75, 150, 300, 375 };
  private int[] ys = { 250, 100, 350, 250 };
  private int dragIndex = NOT_DRAGGING;
  private final static int NEIGHBORHOOD = 15;
  private final static int NOT_DRAGGING = -1;
  public static void main(String[] args) {
    (new BezLab()).setVisible(true);
  }
  BezLab() {
    setSize(500, 450);
    addMouseListener(this);
    addMouseMotionListener(this);
    addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
  }
  public void paint(Graphics g) {
    for (int i = 0; i < 4; i++) {
      if (i == 0 || i == 3)
        g.setColor(Color.blue);
      else
        g.setColor(Color.cyan);
      g.fillOval(xs[i] - 6, ys[i] - 6, 12, 12);
    }
    Graphics2D g2d = (Graphics2D) g;
    g2d.setColor(Color.black);
    GeneralPath path = new GeneralPath();
    path.moveTo(xs[0], ys[0]);
    path.curveTo(xs[1], ys[1], xs[2], ys[2], xs[3], ys[3]);
    g2d.draw(path);
  }
  public void mousePressed(MouseEvent e) {
    dragIndex = NOT_DRAGGING;
    int minDistance = Integer.MAX_VALUE;
    int indexOfClosestPoint = -1;
    for (int i = 0; i < 4; i++) {
      int deltaX = xs[i] - e.getX();
      int deltaY = ys[i] - e.getY();
      int distance = (int) (Math.sqrt(deltaX * deltaX + deltaY * deltaY));
      if (distance < minDistance) {
        minDistance = distance;
        indexOfClosestPoint = i;
      }
    }
    if (minDistance > NEIGHBORHOOD)
      return;
    dragIndex = indexOfClosestPoint;
  }
  public void mouseReleased(MouseEvent e) {
    if (dragIndex == NOT_DRAGGING)
      return;
    xs[dragIndex] = e.getX();
    ys[dragIndex] = e.getY();
    dragIndex = NOT_DRAGGING;
    repaint();
  }
  public void mouseDragged(MouseEvent e) {
    if (dragIndex == NOT_DRAGGING)
      return;
    xs[dragIndex] = e.getX();
    ys[dragIndex] = e.getY();
    repaint();
  }
  public void mouseClicked(MouseEvent e) {
  }
  public void mouseEntered(MouseEvent e) {
  }
  public void mouseExited(MouseEvent e) {
  }
  public void mouseMoved(MouseEvent e) {
  }
}

Complex Paths: Star

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;
import javax.swing.JComponent;
import javax.swing.JFrame;
class MyCanvas extends JComponent {
  public void paint(Graphics g) {
    Graphics2D g2D = (Graphics2D) g;
    Point2D.Float point = new Point2D.Float(100, 100);                     // store start point
    GeneralPath p = new GeneralPath(GeneralPath.WIND_NON_ZERO);
    p.moveTo(point.x, point.y);
    p.lineTo(point.x + 20.0f, point.y - 5.0f);           // Line from start to A
    point = (Point2D.Float)p.getCurrentPoint();
    p.lineTo(point.x + 5.0f, point.y - 20.0f);           // Line from A to B
    point = (Point2D.Float)p.getCurrentPoint();
    p.lineTo(point.x + 5.0f, point.y + 20.0f);           // Line from B to C
    point = (Point2D.Float)p.getCurrentPoint();
    p.lineTo(point.x + 20.0f, point.y + 5.0f);           // Line from C to D
    point = (Point2D.Float)p.getCurrentPoint();
    p.lineTo(point.x - 20.0f, point.y + 5.0f);           // Line from D to E
    point = (Point2D.Float)p.getCurrentPoint();
    p.lineTo(point.x - 5.0f, point.y + 20.0f);           // Line from E to F
    point = (Point2D.Float)p.getCurrentPoint();
    p.lineTo(point.x - 5.0f, point.y - 20.0f);           // Line from F to g
    p.closePath();                                       // Line from G to start
    g2D.draw(p);
  }
}
public class PaintStar {
  public static void main(String[] a) {
    JFrame window = new JFrame();
    window.setBounds(30, 30, 300, 300);
    window.getContentPane().add(new MyCanvas());
    window.setVisible(true);
  }
}