Java tutorial
/* * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * -Redistribution of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of Sun Microsystems, Inc. or the names of contributors may * be used to endorse or promote products derived from this software without * specific prior written permission. * * 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 MIDROSYSTEMS, INC. ("SUN") * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS 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 THIS SOFTWARE, * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that this software is not designed, licensed or intended * for use in the design, construction, operation or maintenance of any * nuclear facility. */ /* * IconDisplayer.java is a 1.4 application that requires the following files: * images/rocketship.gif */ import java.awt.AlphaComposite; import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Insets; import java.awt.Rectangle; import javax.swing.BorderFactory; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JComponent; import javax.swing.JFrame; /* * This component displays a single icon one or more times in a row. The images * are right-aligned, with 5 pixels padding in between. All but the rightmost * image are mostly transparent. */ public class IconDisplayer extends JComponent { private Icon icon; private int preferredNumImages = 2; private int pad = 5; //space between images private Rectangle iconRect = new Rectangle(); private Rectangle clipRect = new Rectangle(); public IconDisplayer(Icon icon, int preferredNumImages, int pad) { this.icon = icon; if (preferredNumImages > 0) { this.preferredNumImages = preferredNumImages; } if (pad >= 0) { this.pad = pad; } //Set a reasonable default border. if (this.pad > 0) { setBorder(BorderFactory.createEmptyBorder(this.pad, this.pad, this.pad, this.pad)); } } public Dimension getPreferredSize() { if (icon != null) { Insets insets = getInsets(); return new Dimension(icon.getIconWidth() * preferredNumImages + pad * (preferredNumImages - 1) + insets.left + insets.right, icon.getIconHeight() + insets.top + insets.bottom); } else { return new Dimension(100, 100); } } public Dimension getMinimumSize() { if (icon != null) { Insets insets = getInsets(); //Return enough space for one icon. return new Dimension(icon.getIconWidth() + insets.left + insets.right, icon.getIconHeight() + insets.top + insets.bottom); } else { return new Dimension(0, 0); } } protected void paintComponent(Graphics g) { if (isOpaque()) { //paint background g.setColor(getBackground()); g.fillRect(0, 0, getWidth(), getHeight()); } if (icon != null) { //Draw the icon over and over, right aligned. Insets insets = getInsets(); int iconWidth = icon.getIconWidth(); int iconX = getWidth() - insets.right - iconWidth; int iconY = insets.top; boolean faded = false; //Copy the Graphics object, which is actually //a Graphics2D object. Cast it so we can //set alpha composite. Graphics2D g2d = (Graphics2D) g.create(); //Draw the icons, starting from the right. //After the first one, the rest are faded. //We won't bother painting icons that are clipped. g.getClipBounds(clipRect); while (iconX >= insets.left) { iconRect.setBounds(iconX, iconY, iconWidth, icon.getIconHeight()); if (iconRect.intersects(clipRect)) { icon.paintIcon(this, g2d, iconX, iconY); } iconX -= (iconWidth + pad); if (!faded) { g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.1f)); faded = true; } } g2d.dispose(); //clean up } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = IconDisplayer.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } /** * Create the GUI and show it. For thread safety, this method should be * invoked from the event-dispatching thread. */ private static void createAndShowGUI() { //Make sure we have nice window decorations. JFrame.setDefaultLookAndFeelDecorated(true); //Create and set up the window. JFrame frame = new JFrame("IconDisplayer"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. ImageIcon ship = createImageIcon("rocketship.gif"); IconDisplayer id = new IconDisplayer(ship, 5, -1); frame.getContentPane().add(id, BorderLayout.CENTER); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } }