import java.awt.*; import java.awt.event.*; import javax.swing.*; import java.net.URL; import java.util.ArrayList; /** * An SillyStamper panel contains a JList of icons, a drawing area where * the user can "stamp" images of the icons, and a few control buttons. * The user clicks an icon in the list to select it, then clicks on the drawing * area to place copies of the selected image. This class can be run as a * main program. * * This program requires the icon image files from the stamper_icons directory. * (The images were taken from a KDE desktop icon collection.) */ public class SillyStamper extends JPanel { /** * The main routine simply opens a window that shows a SillyStamper panel. */ public static void main(String[] args) { JFrame window = new JFrame("Silly Stamper"); SillyStamper content = new SillyStamper(); window.setContentPane(content); window.pack(); window.setResizable(false); Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); window.setLocation( (screenSize.width - window.getWidth())/2, (screenSize.height - window.getHeight())/2 ); window.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE ); window.setVisible(true); } /** * An object of type IconInfo stores the information needed to draw * one icon image on the display area. */ private static class IconInfo { int iconNumber; // an index into the iconImages array. int x, y; // coords of the upper left corner of the image } /** * Contains info for all the icons that have been placed on the * display area. Might contain more than have actually been shown, * because of the Undo command. An icon that is removed from the * display area by an undo is not removed from this list. */ private ArrayList icons = new ArrayList(); private int iconsShown; // Number of icons shown in the display area. private int iconsPlaced; // Number of icons that have been placed. Can be // greater than iconsShown, because of undo/redo. private JList iconList; // The JList from which the user selects the icon for stamping. private JButton undoButton; // A button for removing the most recently added image. private JButton redoButton; // A button for restoring the most recently removed image. private IconDisplayPanel displayPanel; // The display panel. The IconDisplayPanel class is // a nested class, and is defined below. private Image[] iconImages; // The little images that can be "stamped". /** * This class represents the drawing area where the user can stamp images. */ private class IconDisplayPanel extends JPanel implements MouseListener { /** * Draws the display panel, based on the data about what icons are * to be displayed there and what their coordinates are. */ public void paintComponent(Graphics g) { super.paintComponent(g); if (iconImages == null) { g.drawString("Can't load icons.", 10, 30); return; } for (int i = 0; i < iconsShown; i++) { IconInfo info = icons.get(i); g.drawImage(iconImages[info.iconNumber], info.x, info.y, this); } } /** * When the user clicks the display panel, place a copy of the currently selected * icon image at the point where the user clicked. */ public void mousePressed(MouseEvent e) { IconInfo info = new IconInfo(); info.iconNumber = iconList.getSelectedIndex(); info.x = e.getX() - 16; // Offset x-coord, so center of icon is at the point that was clicked. info.y = e.getY() - 16; // Offset y-coord too. if (iconsShown == icons.size()) icons.add(info); else icons.set(iconsShown, info); iconsShown++; iconsPlaced = iconsShown; redoButton.setEnabled(false); undoButton.setEnabled(true); repaint(); // Tell system to redraw the image, with the new data } public void mouseClicked(MouseEvent e) { } // Not used, but required by MouseListener interface. public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent e) { } public void mouseReleased(MouseEvent e) { } } // end nested class IconDisplayPanel /** * The constructor sets up a BorderLayout on the panel with a display panel * in the CENTER position, a list of icon images in the EAST position, and * a JPanel in the SOUTH position that contains two control buttons. */ public SillyStamper() { setLayout(new BorderLayout(2,2)); // Set basic properties of this panel. setBackground(Color.GRAY); setBorder(BorderFactory.createLineBorder(Color.GRAY,2)); displayPanel = new IconDisplayPanel(); // Create and configure the display panel displayPanel.setPreferredSize(new Dimension(400,300)); displayPanel.setBackground( new Color(220,220,255) ); // Very light blue. displayPanel.addMouseListener(displayPanel); add(displayPanel,BorderLayout.CENTER); iconList = createIconList(); // Create the scrolling list of icons. if (iconList == null) return; add( new JScrollPane(iconList), BorderLayout.EAST ); Action undoAction = new AbstractAction("Undo") { public void actionPerformed(ActionEvent evt) { if (iconsShown > 0) { iconsShown--; redoButton.setEnabled(true); displayPanel.repaint(); } } }; Action redoAction = new AbstractAction("Redo") { public void actionPerformed(ActionEvent evt) { if (iconsShown < iconsPlaced) { iconsShown++; if (iconsShown == iconsPlaced) redoButton.setEnabled(false); undoButton.setEnabled(true); displayPanel.repaint(); } } }; undoButton = new JButton(undoAction); redoButton = new JButton(redoAction); undoButton.setEnabled(false); redoButton.setEnabled(false); JPanel buttonPanel = new JPanel(); buttonPanel.add(undoButton); buttonPanel.add(redoButton); add(buttonPanel, BorderLayout.SOUTH); } /** * Create a JList that contains all of the available icon images. */ private JList createIconList() { String[] iconNames = new String[] { "icon5.png", "icon7.png", "icon8.png", "icon9.png", "icon10.png", "icon11.png", "icon24.png", "icon25.png", "icon26.png", "icon31.png", "icon33.png", "icon34.png" }; iconImages = new Image[iconNames.length]; ClassLoader classLoader = getClass().getClassLoader(); Toolkit toolkit = Toolkit.getDefaultToolkit(); try { for (int i = 0; i < iconNames.length; i++) { URL imageURL = classLoader.getResource("stamper_icons/" + iconNames[i]); if (imageURL == null) throw new Exception(); iconImages[i] = toolkit.createImage(imageURL); } } catch (Exception e) { iconImages = null; return null; } // Create an array of objects of type ImageIcon. This is required for // creating the JList. It is easy to create a JList from an array // of ImageIcons -- just pass the array as a parameter to the constructor. // (You could do the same thing with an array of Strings, to get a list // of strings. But JLists can't use other types so easily.) ImageIcon[] icons = new ImageIcon[iconImages.length]; for (int i = 0; i < iconImages.length; i++) icons[i] = new ImageIcon(iconImages[i]); JList list = new JList(icons); // Makes a list containing the image icons from the array. list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); // (Note: With the default selection mode, it would be possible for the user // to select several list items at the same time or to select no item at all.) list.setSelectedIndex(0); // The first item in the list is currently selected. return list; } } // end class SillyStamper