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.JFrame;
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));
        
        ChangeColourTest cct = new ChangeColourTest( new Color(0xFFFF0000) );
        jf.getContentPane().add(cct, "Center");
        
        jf.pack();
        jf.setVisible(true);
    }
    
    // Holders
    private BufferedImage image;
    private Color color;
    
    // Constructor
    public ChangeColourTest( Color c )
    {
        // 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");
        }       
    }    
    
    // Override paint compoenent
    @Override
    public void paintComponent(Graphics g)
    {
        Graphics2D g2D = (Graphics2D)g;
        
        // Paint the test image to the component and change it's colour
        
        // Fill red
        g2D.setColor(color);
        g2D.fillRect(0, 0, getSize().width, getSize().height);
        
        // Paint with composite
        g2D.setComposite(AlphaComposite.DstIn);
        g2D.drawImage( image, 0, 0, image.getWidth(), image.getHeight(), 0, 0, image.getWidth(), image.getHeight(), null);
        
    }
}