Opaque components on transparent Java windows

Question

I\'ve been successful in making java windows transparent, but I\'m having trouble superimposing opaque components on top of those windows. JFrame.setOpacity(0) and AWTUtilities

Answer 1

Using AWTUtilties.setOpaque(Window, boolean), you can get what you want. Here is an example of a half-transparent label (with a red background):

import java.awt.Color;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;

import com.sun.awt.AWTUtilities;

public class Test3 {

    protected static void initUI() {
        JFrame frame = new JFrame("test");
        JLabel label = new JLabel("Label text");
        label.setOpaque(true);
        label.setBackground(new Color(255, 0, 0, 128));
        frame.setUndecorated(true);

        AWTUtilities.setWindowOpaque(frame, false);
        frame.add(label);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                initUI();
            }
        });
    }
}

Here are some screenshots with different values for the alpha chanel (made on a white background):

Alpha set to 128 (half-transparent):

Alpha set to 0 (completely transparent):

Alpha set to 255 (completely opaque):