Java transparent panels & custom effect on panels

Question

I want to have transparent panels in my GUI (if like Windows 7 window headers, it is better).

Before I have used com.sun.awt.AWTUtilities as

AWTUtilities.setWindowOpacity(frame, (float)0.90);

but its parameter is a window like JFrame and couldn't be used for JPanel.

Also I want to have effects on JPanel or JLabel for example luminescence, as is on Windows 7 header buttons. Any other interesting effect is also helpful for me.

Answer 1

Please see the tutorials How to Create Translucent and Shaped Windows and* How to Create Translucent and Shaped Windows*. Follow the links to excellent example depots by @camickr.

For example,

import java.awt.event.*;
import java.awt.Color;
import java.awt.AlphaComposite;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;

public class ButtonTest {

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

            @Override
            public void run() {
                new ButtonTest().createAndShowGUI();
            }
        });
    }

    private JFrame frame;
    private JButton opaqueButton1;
    private JButton opaqueButton2;
    private SoftJButton softButton1;
    private SoftJButton softButton2;

    public void createAndShowGUI() {
        opaqueButton1 = new JButton("Opaque Button");
        opaqueButton2 = new JButton("Opaque Button");
        softButton1 = new SoftJButton("Transparent Button");
        softButton2 = new SoftJButton("Transparent Button");
        opaqueButton1.setBackground(Color.GREEN);
        softButton1.setBackground(Color.GREEN);
        frame = new JFrame();
        frame.getContentPane().setLayout(new java.awt.GridLayout(2, 2, 10, 10));
        frame.add(opaqueButton1);
        frame.add(softButton1);
        frame.add(opaqueButton2);
        frame.add(softButton2);
        frame.setSize(567, 350);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        Timer alphaChanger = new Timer(30, new ActionListener() {

            private float incrementer = -.03f;

            @Override
            public void actionPerformed(ActionEvent e) {
                float newAlpha = softButton1.getAlpha() + incrementer;
                if (newAlpha < 0) {
                    newAlpha = 0;
                    incrementer = -incrementer;
                } else if (newAlpha > 1f) {
                    newAlpha = 1f;
                    incrementer = -incrementer;
                }
                softButton1.setAlpha(newAlpha);
                softButton2.setAlpha(newAlpha);
            }
        });
        alphaChanger.start();
        Timer uiChanger = new Timer(3500, new ActionListener() {

            private LookAndFeelInfo[] laf = UIManager.getInstalledLookAndFeels();
            private int index = 1;

            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    UIManager.setLookAndFeel(laf[index].getClassName());
                    SwingUtilities.updateComponentTreeUI(frame);
                } catch (Exception exc) {
                    exc.printStackTrace();
                }
                index = (index + 1) % laf.length;
            }
        });
        uiChanger.start();
    }

    public static class SoftJButton extends JButton {
        private static final JButton lafDeterminer = new JButton();
        private static final long serialVersionUID = 1L;
        private boolean rectangularLAF;
        private float alpha = 1f;

        public SoftJButton() {
            this(null, null);
        }

        public SoftJButton(String text) {
            this(text, null);
        }

        public SoftJButton(String text, Icon icon) {
            super(text, icon);

            setOpaque(false);
            setFocusPainted(false);
        }

        public float getAlpha() {
            return alpha;
        }

        public void setAlpha(float alpha) {
            this.alpha = alpha;
            repaint();
        }

        @Override
        public void paintComponent(java.awt.Graphics g) {
            java.awt.Graphics2D g2 = (java.awt.Graphics2D) g;
            g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha));
            if (rectangularLAF && isBackgroundSet()) {
                Color c = getBackground();
                g2.setColor(c);
                g.fillRect(0, 0, getWidth(), getHeight());
            }
            super.paintComponent(g2);
        }

        @Override
        public void updateUI() {
            super.updateUI();
            lafDeterminer.updateUI();
            rectangularLAF = lafDeterminer.isOpaque();
        }
    }
}

Answer 2

If you have time I recommend you go through this Filty Rich Clients. By using this book you can learn to create stunning visual and animated effects with Swing and Java 2D. Learn graphics and animation fundamentals as well as advanced rendering techniques.

EDIT: To creat transparent panels call

setOpaque(false)

It'll pass off painting the background to its parent, which may draw its own background.

You can do a screen capture and then use that to paint the background of the panel.