Create Sine Wave
In this section, you will learn how to create a Sine Wave using Java Swing.
We have used Graphics class to draw the Sine Wave. To set the number of cycles,
we have created the following method:
public void setCycles(int newCycles) {
cycles = newCycles;
points = SCALEFACTOR * cycles * 2;
sines = new double[points];
for (int i = 0; i < points; i++) {
double radians = (Math.PI / SCALEFACTOR) * i;
sines[i] = Math.sin(radians);
}
repaint();
} |
Here is the code of SineWave.java:
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
class Diagram extends JPanel {
static final int SCALEFACTOR = 200;
int cycles;
int points;
double[] sines;
int[] pts;
Diagram() {
}
public void setCycles(int newCycles) {
cycles = newCycles;
points = SCALEFACTOR * cycles * 2;
sines = new double[points];
for (int i = 0; i < points; i++) {
double radians = (Math.PI / SCALEFACTOR) * i;
sines[i] = Math.sin(radians);
}
repaint();
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
int maxWidth = getWidth();
double hstep = (double) maxWidth / (double) points;
int maxHeight = getHeight();
pts = new int[points];
for (int i = 0; i < points; i++)
pts[i] = (int) (sines[i] * maxHeight / 2 * .95 + maxHeight / 2);
g.setColor(Color.BLUE);
for (int i = 1; i < points; i++) {
int x1 = (int) ((i - 1) * hstep);
int x2 = (int) (i * hstep);
int y1 = pts[i - 1];
int y2 = pts[i];
g.drawLine(x1, y1, x2, y2);
}
}
}
public class SineWave {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 200);
Diagram sines = new Diagram();
sines.setCycles(5);
frame.getContentPane().add(sines);
frame.setVisible(true);
}
} |
Output will be displayed as:
Download Source Code:
|
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