import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class ChangeColourTest extends JPanel {

    // Main
    public static void main(String[] args) {
        JFrame jf = new JFrame("Test");
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jf.setPreferredSize(new Dimension(150, 150));

        JPanel under = new JPanel();
        under.setBackground(Color.green);
        under.setPreferredSize(new Dimension(150, 150));
//        jf.getLayeredPane().add(under, -1);

        ChangeColourTest cct = new ChangeColourTest( new Color(0xFFFF0000) );
        cct.setOpaque(false);
        jf.add(cct);

        jf.pack();
        jf.setVisible(true);
    }

    // Holders
    private BufferedImage image;
    private Color color;

    // Constructor
    public ChangeColourTest( Color c )
    {
        setBackground(Color.pink);
        // Args
        color = c;

        setPreferredSize(new Dimension(150,150));

        // Load the image
        try {
            image = ImageIO.read(new URL("http://i.imgur.com/Pu6iq.png")); /* A black 'S' on a transparent background. */
        } catch (IOException ex) {
            System.err.println("IOException");
        }

        // create red image
        BufferedImage redVersion = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_ARGB);
        Graphics2D g = (Graphics2D) redVersion.getGraphics();
        g.setColor(Color.red);
        g.fillRect(0, 0, image.getWidth(), image.getHeight());

        // paint original with composite
        g.setComposite(AlphaComposite.DstIn);
        g.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), 0, 0, image.getWidth(), image.getHeight(), null);

        JLabel label = new JLabel();
        label.setPreferredSize(new Dimension(150, 150));
        label.setIcon(new ImageIcon(redVersion));
        add(label);
    }

}