import java.awt.*;

import java.awt.image.BufferedImage;

import javax.swing.Icon;

import javax.swing.ImageIcon;

import javax.swing.JFrame;

import javax.swing.JLabel;

public class ScaleIcon implements Icon {

    private BufferedImage i = null;

    private Icon icon = null;

    public ScaleIcon(Icon icon) {

        this.icon = icon;

    }

    @Override

    public int getIconHeight() {

        return icon.getIconHeight();

    }

    @Override

    public int getIconWidth() {

        return icon.getIconWidth();

    }

    public void paintIcon(Component c, Graphics g, int x, int y) {

        float wid = c.getWidth();

        float hei = c.getHeight();

        int iconWid = icon.getIconWidth();

        int iconHei = icon.getIconHeight();

        Graphics2D g2d = (Graphics2D) g;

        g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);

        g2d.scale(wid / iconWid, hei / iconHei);

        icon.paintIcon(c, g2d, 0, 0);

    }

    public static void main(String[] args) {

        ScaleIcon icon = new ScaleIcon(new ImageIcon(ClassLoader.getSystemResource("img/main.jpg")));

        JLabel label = new JLabel(icon);

        JFrame frame = new JFrame();

        frame.getContentPane().add(label, BorderLayout.CENTER);

//                frame.getContentPane().add(new JButton("click"),BorderLayout.NORTH);

        frame.setSize(800, 600);

        frame.setLocationRelativeTo(null);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setVisible(true);

    }

}