import java.awt.Graphics;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
public class Main extends JFrame {
private BufferedImage bi;
private int zoom = 0;
private static final double ZOOM_AMOUNT = 1.1;
public static void main(String[] args) {
new Main("your.jpg").setVisible(true);
}
private void sizeToZoom() {
double factor = Math.pow(ZOOM_AMOUNT, zoom);
setSize((int) (bi.getWidth() * factor), (int) (bi.getHeight() * factor));
}
public Main(String filename) {
setDefaultCloseOperation(EXIT_ON_CLOSE);
try {
bi = ImageIO.read(new File(filename));
} catch (Exception e) {
e.printStackTrace();
}
sizeToZoom();
addMouseWheelListener(new MouseWheelListener() {
public void mouseWheelMoved(MouseWheelEvent e) {
int steps = e.getWheelRotation();
zoom += steps;
sizeToZoom();
}
});
}
public void paint(Graphics g) {
g.drawImage(bi, 0, 0, getWidth(), getHeight(), this);
}
}