Java Tutorial/2D Graphics/Area

Area.add

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.GeneralPath;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class AreaAdding extends JPanel {
  DrawingCanvas canvas= new DrawingCanvas();
  public AreaAdding() {
    add(canvas);
    canvas.area1 = new Area(canvas.gp);
    canvas.area1.add(canvas.area2);
    canvas.repaint();
  }
  public static void main(String arg[]) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add("Center", new AreaAdding());
    frame.pack();
    frame.setSize(new Dimension(400, 300));
    frame.setVisible(true);
  }
  class DrawingCanvas extends Canvas {
    GeneralPath gp;
    Ellipse2D ellipse;
    Area area1, area2;
    public DrawingCanvas() {
      setBackground(Color.white);
      setSize(350, 250);
      int w = getWidth();
      int h = getHeight();
      gp = new GeneralPath();
      gp.moveTo(w / 8, h / 2);
      gp.lineTo(w / 2, h / 4);
      gp.lineTo(7 * w / 8, h / 2);
      gp.lineTo(w / 2, 3 * h / 4);
      gp.closePath();
      area1 = new Area(gp); 
      ellipse = new Ellipse2D.Double(w / 4, h / 4, w / 2, h / 2);
      area2 = new Area(ellipse); 
    }
    public void paint(Graphics g) {
      Graphics2D g2D = (Graphics2D) g;
      g2D.setStroke(new BasicStroke(2.0f));
      g2D.draw(area1);
      g2D.draw(area2);
    }
  }
}

Area.exclusiveOr

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.GeneralPath;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class AreaExclusiveOr extends JPanel {
  DrawingCanvas canvas;
  public AreaExclusiveOr() {
    canvas = new DrawingCanvas();
    add(canvas);
    
    canvas.area1 = new Area(canvas.gp);
    canvas.area1.exclusiveOr(canvas.area2);
    canvas.repaint();
  }
  public static void main(String arg[]) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add("Center", new AreaExclusiveOr());
    frame.pack();
    frame.setSize(new Dimension(400, 300));
    frame.setVisible(true);
  }
  class DrawingCanvas extends Canvas {
    GeneralPath gp;
    Ellipse2D ellipse;
    Area area1, area2;
    public DrawingCanvas() {
      setBackground(Color.white);
      setSize(350, 250); // width and height of canvas
      int w = getWidth();
      int h = getHeight();
      gp = new GeneralPath();
      gp.moveTo(w / 8, h / 2);
      gp.lineTo(w / 2, h / 4);
      gp.lineTo(7 * w / 8, h / 2);
      gp.lineTo(w / 2, 3 * h / 4);
      gp.closePath();
      area1 = new Area(gp); // General path area object
      ellipse = new Ellipse2D.Double(w / 4, h / 4, w / 2, h / 2);
      area2 = new Area(ellipse); // Ellipse area object
    }
    public void paint(Graphics g) {
      Graphics2D g2D = (Graphics2D) g;
      g2D.setStroke(new BasicStroke(2.0f));
      g2D.draw(area1);
      g2D.draw(area2);
    }
  }
}

Area.intersect

import java.awt.BasicStroke;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.GeneralPath;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class AreaIntersecting extends JPanel {
  DrawingCanvas canvas;
  public AreaIntersecting() {
    canvas = new DrawingCanvas();
    add(canvas);
    
    canvas.area1 = new Area(canvas.gp);
    canvas.area1.intersect(canvas.area2);
    canvas.repaint();
  }
  public static void main(String arg[]) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add("Center", new AreaIntersecting());
    frame.pack();
    frame.setSize(new Dimension(400, 300));
    frame.setVisible(true);
  }
  class DrawingCanvas extends Canvas {
    GeneralPath gp;
    Ellipse2D ellipse;
    Area area1, area2;
    public DrawingCanvas() {
      setBackground(Color.white);
      setSize(350, 250); // width and height of canvas
      int w = getWidth();
      int h = getHeight();
      gp = new GeneralPath();
      gp.moveTo(w / 8, h / 2);
      gp.lineTo(w / 2, h / 4);
      gp.lineTo(7 * w / 8, h / 2);
      gp.lineTo(w / 2, 3 * h / 4);
      gp.closePath();
      area1 = new Area(gp); // General path area object
      ellipse = new Ellipse2D.Double(w / 4, h / 4, w / 2, h / 2);
      area2 = new Area(ellipse); // Ellipse area object
    }
    public void paint(Graphics g) {
      Graphics2D g2D = (Graphics2D) g;
      g2D.setStroke(new BasicStroke(2.0f));
      g2D.draw(area1);
      g2D.draw(area2);
    }
  }
}

Areas support the following boolean operations: Union, Subtraction, Intersection, Exclusive-or (XOR)

/*
 *
 * Copyright (c) 1998 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import javax.swing.JApplet;
import javax.swing.JFrame;
public class Pear extends JApplet {
  Ellipse2D.Double circle, oval, leaf, stem;
  Area circ, ov, leaf1, leaf2, st1, st2;
  public void init() {
    circle = new Ellipse2D.Double();
    oval = new Ellipse2D.Double();
    leaf = new Ellipse2D.Double();
    stem = new Ellipse2D.Double();
    circ = new Area(circle);
    ov = new Area(oval);
    leaf1 = new Area(leaf);
    leaf2 = new Area(leaf);
    st1 = new Area(stem);
    st2 = new Area(stem);
    setBackground(Color.white);
  }
  public void paint(Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    Dimension d = getSize();
    int w = d.width;
    int h = d.height;
    double ew = w / 2;
    double eh = h / 2;
    g2.setColor(Color.green);
    // Creates the first leaf by filling the intersection of two Area objects
    // created from an ellipse.
    leaf.setFrame(ew - 16, eh - 29, 15.0, 15.0);
    leaf1 = new Area(leaf);
    leaf.setFrame(ew - 14, eh - 47, 30.0, 30.0);
    leaf2 = new Area(leaf);
    leaf1.intersect(leaf2);
    g2.fill(leaf1);
    // Creates the second leaf.
    leaf.setFrame(ew + 1, eh - 29, 15.0, 15.0);
    leaf1 = new Area(leaf);
    leaf2.intersect(leaf1);
    g2.fill(leaf2);
    g2.setColor(Color.black);
    // Creates the stem by filling the Area resulting from the subtraction of
    // two Area objects created from an ellipse.
    stem.setFrame(ew, eh - 42, 40.0, 40.0);
    st1 = new Area(stem);
    stem.setFrame(ew + 3, eh - 47, 50.0, 50.0);
    st2 = new Area(stem);
    st1.subtract(st2);
    g2.fill(st1);
    g2.setColor(Color.yellow);
    // Creates the pear itself by filling the Area resulting from the union of
    // two Area objects created by two different ellipses.
    circle.setFrame(ew - 25, eh, 50.0, 50.0);
    oval.setFrame(ew - 19, eh - 20, 40.0, 70.0);
    circ = new Area(circle);
    ov = new Area(oval);
    circ.add(ov);
    g2.fill(circ);
  }
  public static void main(String s[]) {
    JFrame f = new JFrame("Pear");
    f.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
    JApplet applet = new Pear();
    f.getContentPane().add("Center", applet);
    applet.init();
    f.pack();
    f.setSize(new Dimension(150, 200));
    f.show();
  }
}

Area.Subtract

import java.awt.BasicStroke; 
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.geom.GeneralPath;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class AreaSubtracting extends JPanel {
  DrawingCanvas canvas;
  public AreaSubtracting() {
    canvas = new DrawingCanvas();
    add(canvas);
    
    canvas.area1 = new Area(canvas.gp);
    canvas.area1.subtract(canvas.area2);
    canvas.repaint();
  }
  public static void main(String arg[]) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add("Center", new AreaSubtracting());
    frame.pack();
    frame.setSize(new Dimension(400, 300));
    frame.setVisible(true);
  }
  class DrawingCanvas extends Canvas {
    GeneralPath gp;
    Ellipse2D ellipse;
    Area area1, area2;
    public DrawingCanvas() {
      setBackground(Color.white);
      setSize(350, 250); // width and height of canvas
      int w = getWidth();
      int h = getHeight();
      gp = new GeneralPath();
      gp.moveTo(w / 8, h / 2);
      gp.lineTo(w / 2, h / 4);
      gp.lineTo(7 * w / 8, h / 2);
      gp.lineTo(w / 2, 3 * h / 4);
      gp.closePath();
      area1 = new Area(gp); // General path area object
      ellipse = new Ellipse2D.Double(w / 4, h / 4, w / 2, h / 2);
      area2 = new Area(ellipse); // Ellipse area object
    }
    public void paint(Graphics g) {
      Graphics2D g2D = (Graphics2D) g;
      g2D.setStroke(new BasicStroke(2.0f));
      g2D.draw(area1);
      g2D.draw(area2);
    }
  }
}