tempodial.java

java程序中关于多媒体编程 既有文件说明 更有例子 希望大家可以一起学习交流

package javasound;

import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Vector;
import javax.sound.midi.Sequencer;

public class TempoDial extends JPanel {

    private int dotSize = 6;
    private Ellipse2D ellipse;
    private Vector data;
    private Data currentData;
    private Sequencer sequencer;


    public TempoDial() {
        setBackground(new Color(20, 20, 20));

        ellipse = new Ellipse2D.Float(2,20,92,120);
        Vector dots = new Vector();
        PathIterator pi = ellipse.getPathIterator(null, 0.9);
        while ( !pi.isDone() ) {
            float[] pt = new float[6];
            switch ( pi.currentSegment(pt) ) {
                case FlatteningPathIterator.SEG_MOVETO:
                case FlatteningPathIterator.SEG_LINETO:
                    dots.add(new Ellipse2D.Float(pt[0],pt[1],dotSize,dotSize));
            }
            pi.next();
        }
        Vector tmp = new Vector();
        for (int i = 0; i < dots.size(); i++) {
            if (((Ellipse2D) dots.get(i)).getY() >= ellipse.getHeight()/2) {
                tmp.add(dots.get(i));
            }
        }
        dots.removeAll(tmp);

        float x = (float) (ellipse.getX() + ellipse.getWidth()/2);
        float y = (float) (ellipse.getY() + (ellipse.getHeight()/2));
        Vector paths = new Vector(dots.size());
        for (int i = 0; i < dots.size(); i++) {
            GeneralPath gp = new GeneralPath(GeneralPath.WIND_NON_ZERO);
            gp.moveTo(x, y);
            Ellipse2D e1 = (Ellipse2D) dots.get(i);
            gp.lineTo((float) e1.getX(), (float) e1.getY());
            if (i+1 < dots.size()) {
                Ellipse2D e2 = (Ellipse2D) dots.get(i+1);
                gp.lineTo((float) e2.getX(), (float) e2.getY());
            }
            gp.closePath();
            paths.add(gp);
        }

        data = new Vector(paths.size());
        for (int i = 0, tempo = 40; i < paths.size(); i++, tempo+=10) {
            data.add(new Data(tempo, dots.get(i), paths.get(i)));
            if (tempo == 120) {
                currentData = (Data) data.lastElement();
            }
        }

        addMouseMotionListener(new MouseMotionAdapter() {
            public void mouseDragged(MouseEvent e) { processMouse(e); }
        });
        addMouseListener(new MouseAdapter() {
            public void mouseClicked(MouseEvent e) { processMouse(e); }
        });
    }


    private void processMouse(MouseEvent e) {
        if (ellipse.contains(e.getPoint())) {
            for (int i = 0; i < data.size(); i++) {
                currentData = (Data) data.get(i);
                if (currentData.path.contains(e.getPoint())) {
                    break;
                }
            }
            repaint();
            if (sequencer != null) {
                sequencer.setTempoInBPM((float) getTempo());
            }
        }
    }


    public void setSequencer(Sequencer sequencer) {
        this.sequencer = sequencer;
    }


    public float getTempo() {
        return ((float) currentData.tempo);
    }


    public void setTempo(float tempo) {
        for (int i = 0; i < data.size(); i++) {
            currentData = (Data) data.get(i);
            if (currentData.tempo == tempo) {
                break;
            }
        }
        repaint();
    }


    public void paint(Graphics g) {
	Dimension d = getSize();
        Graphics2D g2 = (Graphics2D) g;
        g2.setBackground(getBackground());
        g2.clearRect(0, 0, d.width, d.height);
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);

        double x = ellipse.getWidth()/2+ellipse.getX()+dotSize/2;
        double y = ellipse.getHeight()/2;
        double x2 = currentData.dot.getX() + dotSize/2;
        double y2 = currentData.dot.getY() + dotSize/2;
        Ellipse2D e = new Ellipse2D.Double(x-5,y-5,10,10);

        Color jfcBlue = new Color(204, 204, 255);
        g2.setColor(jfcBlue);
        g2.setStroke(new BasicStroke(3));
        g2.draw(new Line2D.Double(e.getX()+5, e.getY()+5, x2, y2));
        g2.fill(e);
        g2.setFont(new Font("serif", Font.BOLD, 12));
        g2.drawString(String.valueOf(currentData.tempo) + " bpm", 2, 12);

        g2.fill(currentData.dot);
        g2.setStroke(new BasicStroke(1.5f));
        g2.setColor(jfcBlue.darker());
        for (int i = 0; i < data.size(); i++) {
            g2.draw(((Data) data.get(i)).dot);
        }
    }


    public Dimension getPreferredSize() {
        return new Dimension(105,70);
    }

    public Dimension getMaximumSize() {
        return getPreferredSize();
    }


    class Data extends Object {
        int tempo; Ellipse2D dot; GeneralPath path;
        public Data(int tempo, Object dot, Object path) {
            this.tempo = tempo;
            this.dot = (Ellipse2D) dot;
            this.path = (GeneralPath) path;
        }
    }


    public static void main(String argv[]) {
        JFrame f = new JFrame("Tempo Dial");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        f.getContentPane().add("Center", new TempoDial());
        f.pack();
        f.setSize(new Dimension(200,140));
        f.setVisible(true);
    }
}