Plotting a Sine Wave

import javax.swing.*;

import java.awt.*;

public class SineWavePlot extends JPanel {

    @Override

    protected void paintComponent(Graphics g) {

        super.paintComponent(g);

        drawSineWave(g);

    }

    private void drawSineWave(Graphics g) {

        Graphics2D g2d = (Graphics2D) g;

        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        g2d.setColor(Color.BLUE);

        int width = getWidth();

        int height = getHeight();

        int midY = height / 2;

        double frequency = 16 * Math.PI / width;

        int amplitude = height / 4;

        int prevX = 0;

        int prevY = midY;

        for (int x = 1; x < width; x++) {

            int y = (int) (midY + amplitude * Math.sin(frequency * x));

            g2d.drawLine(prevX, prevY, x, y);

            prevX = x;

            prevY = y;

        }

    }

    private static void createAndShowGUI() {

        JFrame frame = new JFrame("Sine Wave Plot");

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setSize(800, 600);

        frame.add(new SineWavePlot());

        frame.setVisible(true);

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(SineWavePlot::createAndShowGUI);

    }

}

Explanation

1. Creating the Custom JPanel (SineWavePlot):

   • The SineWavePlot class extends JPanel and overrides the paintComponent method to perform custom drawing.
   • super.paintComponent(g) ensures that the panel is properly rendered before adding custom drawings.

2. Drawing the Sine Wave:

   • Graphics2D is used for better control and rendering quality.
   • Anti-aliasing is enabled for smoother graphics.
   • The sine wave is drawn by calculating the y-coordinate for each x-coordinate based on the sine function.
   • A loop iterates through the x-coordinates and uses g2d.drawLine to connect consecutive points on the sine wave.

3. Creating and Showing the GUI:

   • The createAndShowGUI method sets up the JFrame, adds the custom JPanel, and makes the frame visible.
   • The main method uses SwingUtilities.invokeLater to ensure the GUI creation and updates are handled on the Event Dispatch Thread.

This program creates a window displaying a sine wave. You can run this code to see the sine wave plotted using Java Swing.