JAVA Applet钢琴模拟程序java源码

// Keyboard.java //Download:http://www.codefans.net /* * Portions of Keyboard's source code were excerpted from Sun's MidiSynth.java * source file. I've included Sun's original copyright and license, to be fair * to Sun. * * Copyright (c) 1999 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.*; import java.awt.event.*; import java.util.Vector; import javax.sound.midi.*; import javax.swing.*; /* This class creates a keyboard component that knows how to play a specific instrument. */ public class Keyboard extends JPanel { public final static Color KEY_BLUE = new Color (204, 204, 255); public final static int KEY_HEIGHT = 80, KEY_WIDTH = 16; private Key theKey; private MidiChannel channel; private Synthesizer synthesizer; private Vector blackKeys = new Vector (); private Vector keys = new Vector (); private Vector whiteKeys = new Vector (); public Keyboard () { setLayout (new BorderLayout ()); setPreferredSize (new Dimension (42*KEY_WIDTH+1, KEY_HEIGHT+1)); int transpose = 24; int [] whiteIDs = { 0, 2, 4, 5, 7, 9, 11 }; for (int i = 0, x = 0; i < 6; i++) { for (int j = 0; j < 7; j++, x += KEY_WIDTH) { int keyNum = i * 12 + whiteIDs [j] + transpose; whiteKeys.add (new Key (x, 0, KEY_WIDTH, KEY_HEIGHT, keyNum)); } } for (int i = 0, x = 0; i < 6; i++, x += KEY_WIDTH) { int keyNum = i * 12 + transpose; blackKeys.add (new Key ((x += KEY_WIDTH)-4, 0, KEY_WIDTH/2, KEY_HEIGHT/2, keyNum+1)); blackKeys.add (new Key ((x += KEY_WIDTH)-4, 0, KEY_WIDTH/2, KEY_HEIGHT/2, keyNum+3)); x += KEY_WIDTH; blackKeys.add (new Key ((x += KEY_WIDTH)-4, 0, KEY_WIDTH/2, KEY_HEIGHT/2, keyNum+6)); blackKeys.add (new Key ((x += KEY_WIDTH)-4, 0, KEY_WIDTH/2, KEY_HEIGHT/2, keyNum+8)); blackKeys.add (new Key ((x += KEY_WIDTH)-4, 0, KEY_WIDTH/2, KEY_HEIGHT/2, keyNum+10)); } keys.addAll (blackKeys); keys.addAll (whiteKeys); addMouseListener (new MouseAdapter () { public void mousePressed (MouseEvent e) { // Identify the key that was pressed. A null // value indicates something other than a key // was pressed. theKey = getKey (e.getPoint ()); // If a key was pressed ... if (theKey != null) { // Tell key to start playing note. theKey.on (); // Update key's visual appearance. repaint (); } } public void mouseReleased (MouseEvent e) { if (theKey != null) { // Tell key to stop playing note. theKey.off (); // Update key's visual appearance. repaint (); } } public void mouseExited (MouseEvent e) { // This method is called if the mouse is moved // off the keyboard component. If a key was // pressed, we release that key. if (theKey != null) { // Tell key to stop playing note. theKey.off (); // Update key's visual appearance. repaint (); // The following assignment is needed so // that we don't execute the code within // mouseReleased()'s if statement should we // release a key after exiting the keyboard // component. There is no need to tell the // key to stop playing a note after we have // already told it to do so. Furthermore, // we prevent an unnecessary repaint. theKey = null; } } public Key getKey (Point point) { // Identify the key that was clicked. for (int i = 0; i < keys.size (); i++) { if (((Key) keys.get (i)).contains (point)) return (Key) keys.get (i); } return null; } }); } public boolean chooseInstrument (int instrumentID) { if (channel == null) return false; // Select new instrument based on ID. channel.programChange (instrumentID); return true; } public String [] getInstruments () { if (synthesizer == null) return null; Instrument [] instruments = synthesizer.getLoadedInstruments (); String [] ins = new String [instruments.length]; for (int i = 0; i < instruments.length; i++) ins [i] = instruments [i].toString (); return ins; } public void paint (Graphics g) { Graphics2D g2 = (Graphics2D) g; Dimension d = getSize (); g2.setBackground (getBackground ()); g2.clearRe