import java.awt.*; import java.awt.event.*; import java.awt.image.BufferedImage; import javax.swing.*; /** * Demonstrates a toolbar and the use of image icons on buttons. The toolbar * contains a radio group with three JRadioButtons and a button, all of which * use custom icons. The actual program just lets the user draw curves * in three different colors. This class can be run as a stand-alone program. */ public class ToolBarDemo extends JPanel { /** * The main routine simply opens a window that shows a ToolBarDemo panel. */ public static void main(String[] args) { JFrame window = new JFrame("ToolBarDemo"); ToolBarDemo content = new ToolBarDemo(); 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); } /** * Defines the display area of the program, where the user can draw curves * in various colors. (This class demonstrates resizing an off-screen canvas * when the size of the display changes. The size can change if the user * drags the toolbar out of the window or to a new position.) */ private class Display extends JPanel implements MouseListener, MouseMotionListener { private BufferedImage OSC; // Off-screen canvas. private Color currentColor = Color.RED; // Current drawing color. private int prevX, prevY; // Previous mouse position, during mouse drags. private BasicStroke stroke; // Stroke used for drawing. Display() { // constructor. addMouseListener(this); addMouseMotionListener(this); setPreferredSize(new Dimension(300,300)); stroke = new BasicStroke(3,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND); } void setCurrentColor(Color c) { // change current drawing color currentColor = c; } void clear() { // clear the drawing area by filling it with white if (OSC != null) { Graphics g = OSC.getGraphics(); g.setColor(Color.WHITE); g.fillRect(0,0,getWidth(),getHeight()); g.dispose(); repaint(); } } public void paintComponent(Graphics g) { // just copies OSC to screen checkImage(); g.drawImage(OSC,0,0,null); } void checkImage() { // create or resize OSC if necessary if (OSC == null) { // Create the OSC, with a size to match the size of the panel. OSC = new BufferedImage(getWidth(),getHeight(),BufferedImage.TYPE_INT_RGB); clear(); } else if (OSC.getWidth() != getWidth() || OSC.getHeight() != getHeight()) { // OSC size does not match the panel's size, so create a new OSC and // copy the picture in the old OSC to the new one. This will scale // the current image to fit the new size. BufferedImage newOSC; newOSC = new BufferedImage(getWidth(),getHeight(),BufferedImage.TYPE_INT_RGB); Graphics g = newOSC.getGraphics(); g.drawImage(OSC,0,0,getWidth(),getHeight(),null); g.dispose(); OSC = newOSC; } } public void mousePressed(MouseEvent e) { prevX = e.getX(); prevY = e.getY(); } public void mouseDragged(MouseEvent e) { Graphics2D g2 = (Graphics2D)OSC.getGraphics(); g2.setColor(currentColor); g2.setStroke(stroke); g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.drawLine(prevX,prevY,e.getX(),e.getY()); g2.dispose(); repaint(); prevX = e.getX(); prevY = e.getY(); } public void mouseReleased(MouseEvent e) { } public void mouseMoved(MouseEvent e) { } public void mouseClicked(MouseEvent e) { } public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent e) { } } private Display display; // The display area of the program. /** * Constructor adds a display and a toolbar to the program. The * advice for using a toolbar is to place the toolbar in one of * the edge positions of a BorderLayout, and to put nothing in any * of the other three edge positions. The user might be able * to drag the toolbar from one edge position to another. */ public ToolBarDemo() { setLayout(new BorderLayout(2,2)); setBackground(Color.GRAY); setBorder(BorderFactory.createLineBorder(Color.GRAY,2)); display = new Display(); add(display, BorderLayout.CENTER); JToolBar toolbar = new JToolBar(); add(toolbar, BorderLayout.NORTH); ButtonGroup group = new ButtonGroup(); toolbar.add( makeColorRadioButton(Color.RED,group,true) ); toolbar.add( makeColorRadioButton(Color.GREEN,group,false) ); toolbar.add( makeColorRadioButton(Color.BLUE,group,false) ); toolbar.addSeparator(new Dimension(20,20)); toolbar.add( makeClearButton() ); } /** * Create a JRadioButton and add it to a specified button group. The button * is meant for selecting a drawing color in the display. The color is used to * create two custom icons, one for the unselected state of the button and one * for the selected state. These icons are used instead of the usual * radio button icons. * @param c the color of the button, and the color to be used for drawing. * (Note that c has to be "final" since it is used in the anonymous inner * class that defines the response to ActionEvents on the button.) * @param grp the ButtonGroup to which the radio button will be added. * @param selected if true, then the state of the button is set to selected. * @return the radio button that was just created. */ private JRadioButton makeColorRadioButton(final Color c, ButtonGroup grp, boolean selected) { /* Create an ImageIcon for the normal, unselected state of the button, using a BufferedImage that is drawn here from scratch. */ BufferedImage image = new BufferedImage(30,30,BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); g.setColor(Color.LIGHT_GRAY); g.fillRect(0,0,30,30); g.setColor(c); g.fill3DRect(1, 1, 24, 24, true); g.dispose(); Icon unselectedIcon = new ImageIcon(image); /* Create an ImageIcon for the selected state of the button. */ image = new BufferedImage(30,30,BufferedImage.TYPE_INT_RGB); g = image.getGraphics(); g.setColor(Color.DARK_GRAY); g.fillRect(0,0,30,30); g.setColor(c); g.fill3DRect(3, 3, 24, 24, false); g.dispose(); Icon selectedIcon = new ImageIcon(image); /* Create and configure the button. */ JRadioButton button = new JRadioButton(unselectedIcon); button.setSelectedIcon(selectedIcon); button.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { // The action for this button sets the current drawing color // in the display to c. display.setCurrentColor(c); } }); grp.add(button); if (selected) button.setSelected(true); return button; } // end makeColorRadioButton /** * Create a JButton that can be used to clear the display. The button has * no text and its icon is a custom icon that shows a big X. The icon is * created by drawing it on a Buffered image and using that image to * create an ImageIcon. The button has tooltip text "Clear the Display". */ private JButton makeClearButton() { BufferedImage image = new BufferedImage(24,24,BufferedImage.TYPE_INT_RGB); Graphics2D g2 = (Graphics2D)image.getGraphics(); g2.setColor(Color.LIGHT_GRAY); g2.fillRect(0,0,24,24); g2.setStroke( new BasicStroke(3)); g2.setColor(Color.BLACK); g2.drawLine(4,4,20,20); g2.drawLine(4,20,20,4); g2.dispose(); Icon clearIcon = new ImageIcon(image); Action clearAction = new AbstractAction(null,clearIcon) { public void actionPerformed(ActionEvent evt) { display.clear(); } }; clearAction.putValue(Action.SHORT_DESCRIPTION, "Clear the Display"); JButton button = new JButton(clearAction); return button; } }