Java tutorial
/* This program is a part of the companion code for Core Java 8th ed. (http://horstmann.com/corejava) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.awt.EventQueue; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.geom.Ellipse2D; import java.awt.geom.Line2D; import java.awt.geom.Rectangle2D; import javax.swing.JComponent; import javax.swing.JFrame; /** * @version 1.32 2007-04-14 * @author Cay Horstmann */ public class DrawTest { public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { DrawFrame frame = new DrawFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } }); } } /** * A frame that contains a panel with drawings */ class DrawFrame extends JFrame { public DrawFrame() { setTitle("DrawTest"); setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); // add panel to frame DrawComponent component = new DrawComponent(); add(component); } public static final int DEFAULT_WIDTH = 400; public static final int DEFAULT_HEIGHT = 400; } /** * A component that displays rectangles and ellipses. */ class DrawComponent extends JComponent { public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g; // draw a rectangle double leftX = 100; double topY = 100; double width = 200; double height = 150; Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height); g2.draw(rect); // draw the enclosed ellipse Ellipse2D ellipse = new Ellipse2D.Double(); ellipse.setFrame(rect); g2.draw(ellipse); // draw a diagonal line g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height)); // draw a circle with the same center double centerX = rect.getCenterX(); double centerY = rect.getCenterY(); double radius = 150; Ellipse2D circle = new Ellipse2D.Double(); circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius); g2.draw(circle); } }