Develop Reference

Why does this program only display the last graphic?

Im using JPanel and JFrame to create a program that can draw lines and circles. The problem is that my program only redraws the last object added.
I have tried moving around the repaint. For some reason, when I directly draw shapes onto the graphic in paintComponent(), they show up and refresh each frame. However, I have methods inside of paintComponent that pass the graphic variable to elsewhere methods that draw to the graphic object, these are the shapes that do not show up.
Painter Class
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Painter implements ActionListener, MouseListener, MouseMotionListener {
/**
*
*/
Color temp = Color.RED;
// 0 = line, 1 = circle
int object = 0;
PaintingPanel canvas;
Point startPoint = new Point();
Point endPoint = new Point();
Painter() {
//buttons
JButton circleBut = new JButton();
JButton lineBut = new JButton();
//frame
//close operation
//resizes
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
//holder holds the information
JPanel holder = new JPanel();
JPanel leftPanel = new JPanel();
holder.setLayout(new BorderLayout());
leftPanel.setLayout(new GridLayout(3, 1)); // 3 by 1 grid
JPanel northPanel = new JPanel();
northPanel.setLayout(new GridLayout(1, 2)); // 3 by 1 grid
frame.add(holder);
// circle and line buttons
circleBut.setText("Circle");
lineBut.setText("Line");
northPanel.add(circleBut);
northPanel.add(lineBut);
circleBut.setActionCommand("1");
lineBut.setActionCommand("0");
//
holder.add(northPanel, BorderLayout.NORTH);
// red
JButton redPaint = new JButton();
redPaint.setBackground(Color.RED);
redPaint.setOpaque(true);
redPaint.setBorderPainted(false);
leftPanel.add(redPaint);
redPaint.setActionCommand("red");
// green
JButton greenPaint = new JButton();
greenPaint.setBackground(Color.GREEN);
greenPaint.setOpaque(true);
greenPaint.setBorderPainted(false);
leftPanel.add(greenPaint);
greenPaint.setActionCommand("green");
// blue
JButton bluePaint = new JButton();
bluePaint.setBackground(Color.BLUE);
bluePaint.setOpaque(true);
bluePaint.setBorderPainted(false);
leftPanel.add(bluePaint);
bluePaint.setActionCommand("blue");
holder.add(leftPanel, BorderLayout.WEST);
// still need to add painting panel to the CENTER panel
canvas = new PaintingPanel();
holder.add(canvas, BorderLayout.CENTER);
circleBut.addActionListener(this);
lineBut.addActionListener(this);
redPaint.addActionListener(this);
greenPaint.addActionListener(this);
bluePaint.addActionListener(this);
canvas.addMouseListener(this);
//holder.addMouseMotionListener(this);
// still need to add chat panel to the SOUTH panel
frame.setContentPane(holder);
frame.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("red")) {
temp = Color.RED;
System.out.println("received r");
} else if (e.getActionCommand().equals("green")) {
temp = Color.GREEN;
System.out.println("received g");
} else if (e.getActionCommand().equals("blue")) {
temp = Color.BLUE;
System.out.println("received b");
} else if (e.getActionCommand().equals("0")) {
object = 0;
System.out.println("received 0");
} else if (e.getActionCommand().equals("1")) {
object = 1;
System.out.println("received 1");
}
}
#Override
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseClicked(MouseEvent e) {
}
#Override
public void mousePressed(MouseEvent e) {
startPoint.setLocation(e.getPoint());
}
#Override
public void mouseReleased(MouseEvent e) {
// and this one
endPoint.setLocation(e.getPoint());
if (object == 0) {
canvas.addPrimitive(new Line(startPoint, endPoint, temp));
}
if (object == 1){
canvas.addPrimitive(new Circle(startPoint, endPoint, temp));
}
canvas.repaint();
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
public static void main(String[] args) {
Painter game1 = new Painter();
}
}
PaintingPrimitives:
`
import java.awt.Graphics;
import java.awt.Color;
public abstract class PaintingPrimitive{
Color color;
PaintingPrimitive(Color color) {
this.color = color;
}
// This is an example of the Template Design Pattern
// this is all invariant code
public final void draw(Graphics g) {
g.setColor(color);
drawGeometry(g);
}
public void setColor(Color color) {
this.color = color;
}
protected abstract void drawGeometry(Graphics g);
}
Line Class:
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Color;
public class Line extends PaintingPrimitive{
Point startPoint = new Point();
Point endPoint = new Point();
public Line(Point start, Point end, Color c) {
super(c);
this.startPoint = start;
this.endPoint = end;
}
public void drawGeometry(Graphics g) {
System.out.println("graw geo called");
g.drawLine(startPoint.x, startPoint.y, endPoint.x, endPoint.y);
}
#Override
public String toString() {
return "Line";
}
}
Painting Panel:
import java.util.ArrayList;
import javax.swing.JPanel;
import java.awt.Graphics;
import java.awt.Color;
public class PaintingPanel extends JPanel {
ArrayList<PaintingPrimitive> primitives = new ArrayList<PaintingPrimitive>();
PaintingPanel() {
setBackground(Color.WHITE);
}
public void addPrimitive(PaintingPrimitive obj) {
primitives.add(obj);
this.repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// i'm confident that this is not painting to the right graphics
for (PaintingPrimitive shape : primitives) {
//g.dispose();
//this line works. this line is drawn each time its updated.
g.drawLine(0,0,100,100);
shape.draw(g);
}
}
}
`

Okay, that was weird, until it wasn't. Your problem basic centers around...
public void mousePressed(MouseEvent e) {
startPoint.setLocation(e.getPoint());
}
#Override
public void mouseReleased(MouseEvent e) {
// and this one
endPoint.setLocation(e.getPoint());
if (object == 0) {
canvas.addPrimitive(new Line(startPoint, endPoint, temp));
}
You create a single instance of startPoint and endPoint and simply update the location of each Point. You then pass these to each primitive you create. This means that each primitive is using the SAME instance of startPoint and endPoint. So, each time you call setLocation ALL the primitives are been updated.
Instead, do something more like...
#Override
public void mousePressed(MouseEvent e) {
startPoint = new Point(e.getPoint());
}
#Override
public void mouseReleased(MouseEvent e) {
// and this one
endPoint = new Point(e.getPoint());
And because I'm paranoid and don't trust any one, I'd probably also do...
public class Line extends PaintingPrimitive {
Point startPoint = new Point();
Point endPoint = new Point();
public Line(Point start, Point end, Color c) {
super(c);
this.startPoint = new Point(start);
this.endPoint = new Point(end);
}
Just to be sure

How do I clear my Jpanel but keep the grid lines?

I'm drawing lines on a JPanel using a paint component and graphics 2D, but the background of the JPanel is set to a grid which is drawn when the user enters some dimensions. How do I clear the lines drawn on the JPanel when a button is clicked but regenerate a fresh panel again with the grid lines drawn? With the action event method for the clear button, I've tried using repaint(), removeAll() and creating a new instance of the JPanel but none of that seems to work.
Here is the code for the class with the main Panel and button functions:
package floorplan;
/**
*
* #author xodkx
*/
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.SwingUtilities;
public class FloorPlan extends JFrame
{
private JPanel backPanel = new JPanel();
private JPanel toolsPanel = new JPanel();
private JFrame chooseFurniture;
private JFrame chooseFixture;
private JFrame chooseFramework;
private JButton furnitureButton = new JButton();
private JButton fixturesButton = new JButton();
private JButton frameworkButton = new JButton();
private JButton deleteButton = new JButton();
private JButton saveButton = new JButton();
private JButton clearButton = new JButton();
private JButton closeButton = new JButton();
private JRadioButton wall = new JRadioButton("Wall");
private JRadioButton door = new JRadioButton("Door");
private JRadioButton window = new JRadioButton("Window");
Floor floor = new Floor();
public FloorPlan()
{
super("Floor Plan Generator");
createWindow();
buttonFunctions();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
private void createWindow()
{
backPanel.setLayout(new BorderLayout());
backPanel.setBorder(BorderFactory.createEmptyBorder(200, 200, 200, 200));
GridLayout panelLayout = new GridLayout();
frameworkButton.setText("Framework");
fixturesButton.setText("Fixtures");
furnitureButton.setText("Furniture");
deleteButton.setText("Delete");
saveButton.setText("Save");
clearButton.setText("Clear");
add(backPanel, BorderLayout.CENTER);
backPanel.add(toolsPanel, BorderLayout.NORTH);
backPanel.add(floor, BorderLayout.CENTER);
backPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
toolsPanel.add(frameworkButton);
toolsPanel.add(fixturesButton);
toolsPanel.add(furnitureButton);
toolsPanel.add(deleteButton);
toolsPanel.add(saveButton);
toolsPanel.add(clearButton);
add(backPanel);
}
private void buttonFunctions()
{
frameworkButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(final ActionEvent e)
{
chooseFramework = new JFrame("Pick A Framework");
chooseFramework.setSize(250,250);
chooseFramework.setLayout(new GridLayout(4,1));
chooseFramework.add(wall);
chooseFramework.add(door);
chooseFramework.add(window);
chooseFramework.add(closeButton);
closeButton.setText("Close");
wall.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
floor.setFramework(Framework.WALL);
}});
door.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
floor.setColor(Color.RED);
floor.setFramework(Framework.DOOR);
}});
window.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
floor.setColor(Color.BLUE);
floor.setFramework(Framework.WALL);
}});
closeButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
chooseFramework.setVisible(false);
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
chooseFramework.setVisible(true);
}
});
furnitureButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(final ActionEvent e)
{
chooseFurniture = new JFrame("Pick Furniture to add");
chooseFurniture.setSize(250,250);
chooseFurniture.setLayout(new GridLayout(4,1));
chooseFurniture.add(closeButton);
closeButton.setText("Close");
closeButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
chooseFurniture.setVisible(false);
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
chooseFurniture.setVisible(true);
}
});
fixturesButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(final ActionEvent e)
{
chooseFixture = new JFrame("Pick Furniture to add");
chooseFixture.setSize(250,250);
chooseFixture.setLayout(new GridLayout(4,1));
chooseFixture.add(closeButton);
closeButton.setText("Close");
closeButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
chooseFixture.setVisible(false);
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
chooseFixture.setVisible(true);
}
});
**clearButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(final ActionEvent e)
{
**//THIS IS WHERE I WANT TO CLEAR THE JPANEL WHEN THIS BUTTON IS CLICKED**
}
});**
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
FloorPlan floorPlan = new FloorPlan();
}
});
}
}
Here is the class that does all the graphics stuff and draws onto the JPanel
package floorplan;
/**
*
* #author xodkx
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.BufferedImage;
import java.awt.event.MouseListener;
public class Floor extends JPanel implements MouseListener, MouseMotionListener
{
private static final int WIDTH = Integer.parseInt(JOptionPane.showInputDialog("Please
enter the width of your room"));
private static final int LENGTH = Integer.parseInt(JOptionPane.showInputDialog("Please
enter the width of your room"));
private static final Color BACKGROUND = Color.WHITE;
private static final Color INITIAL_COLOUR = Color.BLACK;
private static final Framework INITIAL_FRAMEWORK = Framework.WALL;
private MouseState state = MouseState.IDLE;
private Framework frameworkType = INITIAL_FRAMEWORK;
private Color colour = INITIAL_COLOUR;
private Point start = null;
private Point end = null;
private Point startpt = null;
private Point endpt = null;
private BufferedImage bufImage = null;
public Floor()
{
setPreferredSize(new Dimension(LENGTH,WIDTH));
setBackground(Color.white);
setBorder(BorderFactory.createLineBorder (Color.black, 5));
this.addMouseListener(this);
this.addMouseMotionListener(this);
}
public void setColor(Color color)
{
colour = color;
}
public void setFramework(Framework framework)
{
frameworkType = framework;
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
if(bufImage == null)
{
int h = this.getHeight();
int w = this.getWidth();
bufImage = (BufferedImage)this.createImage(h,w);
Graphics2D gc = bufImage.createGraphics();
gc.setColor(BACKGROUND);
gc.fillRect(0, 0, w, h);
}
g2.drawImage(bufImage,null,0,0);
drawGrid(g2);
if(state == MouseState.DRAGGING)
{
createComponent(g2);
}
}
public void drawGrid(Graphics g2)
{
int gridDivisions = 20;
int divisionSize = WIDTH/gridDivisions;
int grid = WIDTH*LENGTH;
g2.setColor(Color.lightGray);
for(int i=1; i<grid; i++)
{
int x = i * divisionSize;
g2.drawLine(x,0,x,getSize().height);
}
for(int i=1; i<grid; i++)
{
int y = i*divisionSize;
g2.drawLine(0,y,getSize().width,y);
}
}
public void createComponent(Graphics2D g2)
{
g2.setColor(colour);
switch (frameworkType)
{
case WALL:
g2.setStroke(new BasicStroke(5));
g2.drawLine(start.x, start.y, end.x,end.y);
break;
case DOOR:
g2.setStroke(new BasicStroke(5));
g2.drawLine(start.x, start.y, end.x,end.y);
break;
case WINDOW:
g2.setStroke(new BasicStroke(5));
g2.drawLine(start.x, start.y, end.x,end.y);
break;
default:
g2.drawString("test", 10, 20);
break;
}
}
#Override
public void mousePressed(MouseEvent e)
{
state = MouseState.DRAGGING;
start = e.getPoint();
end = start;
}
#Override
public void mouseDragged(MouseEvent e)
{
state = MouseState.DRAGGING;
end = e.getPoint();
this.repaint();
}
#Override
public void mouseReleased(MouseEvent e)
{
end = e.getPoint();
if(state == MouseState.DRAGGING)
{
state = MouseState.IDLE;
createComponent(bufImage.createGraphics());
this.repaint();
}
}
#Override
public void mouseClicked(MouseEvent e)
{
}
#Override
public void mouseEntered(MouseEvent e)
{
}
#Override
public void mouseExited(MouseEvent e)
{
}
#Override
public void mouseMoved(MouseEvent e)
{
}
}

It is not clear exactly how do you want to incorporate the logic of displaying the grid. Here is an example how to toggle it just to give you the idea. In Floor class add boolean flag that controls whether the grid is displayed or not. Then in Floor.paintComponent() draw grid based on the value of this boolean flag. Changing the flag's value should trigger a repaint. Then, change the value of this flag from FloorPlan class, in response to an action or some other program logic. Here is a simple implementation that toggles grid when clear button is clicked :
Floor class:
private boolean displayGrid = true;
public boolean isDisplayGrid() {
return displayGrid;
}
public void setDisplayGrid(boolean displayGrid) {
this.displayGrid = displayGrid;
repaint();
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
...
if (displayGrid)
drawGrid(g2);
}
FloorPlan class:
clearButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
floor.setDisplayGrid(!floor.isDisplayGrid());
}
});
EDIT:
Seems that I totally misinterpreted your question. If I understand correctly you want to clear the drawings upon a button click. Looks like all the drawings are done on the bufImage in the Floor class. Simply reset this image, ie:
Floor class:
public void clear() {
bufImage.flush();
bufImage = null;
repaint();
}
FloorPlan class:
clearButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(final ActionEvent e) {
floor.clear();
}
});

You could use a for loop with panel.remove the buttons (instead of panel.add)

Changing Swing GUI Default Look and Feel in real time

Before showing the GUI, if i have a code block like this:
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("GTK+".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception ex) {}
Here for example, i am using theme GTK+ in ubunut. Other options like Nimbus etc can be used. Now once i launch the app, it loads and show this theme. But is there anyway i can change the theme in real time. Because if i change it i have to close the GUI and load it again with new theme?

Is possible change Look and Feel on Runtime by invoke SwingUtilities#updateComponentTreeUI, 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 {
private JFrame frame;
private JButton opaqueButton1;
private JButton opaqueButton2;
private SoftJButton softButton1;
private SoftJButton softButton2;
private Timer alphaChanger;
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(700, 300);
frame.setLocation(150, 100);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
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 final LookAndFeelInfo[] laf = UIManager.getInstalledLookAndFeels();
private int index = 1;
#Override
public void actionPerformed(ActionEvent e) {
try {
UIManager.setLookAndFeel(laf[index].getClassName());
SwingUtilities.updateComponentTreeUI(frame);
opaqueButton1.setText(laf[index].getClassName());
softButton1.setText(laf[index].getClassName());
} catch (Exception exc) {
exc.printStackTrace();
}
index = (index + 1) % laf.length;
}
});
uiChanger.start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ButtonTest().createAndShowGUI();
}
});
}
private 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;
SoftJButton() {
this(null, null);
}
SoftJButton(String text) {
this(text, null);
}
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();
}
}
}

Java transparent panels & custom effect on panels

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.

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();
}
}
}

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.

Drawing transculent rectangle

I was a problem with drawing rectangle using mouse. I have solve my problem and I get results what I want. But I have a small problem. If I want to start draw rectangle when I click mouse button, text in my button change. This is small difference but I don't want see this. Here is code:
package draw;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import javax.swing.event.*;
public class Selection extends JPanel
implements ChangeListener {
/**
*
*/
private static final long serialVersionUID = 1L;
private static final int WIDE = 640;
private static final int HIGH = 640;
private List<Node> nodes = new ArrayList<Node>();
private Point mousePt = new Point(WIDE / 2, HIGH / 2);
private Rectangle mouseRect = new Rectangle();
private boolean selecting = false;
public static void main(String[] args) throws Exception {
EventQueue.invokeLater(new Runnable() {
public void run() {
JFrame f = new JFrame("GraphPanel");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Selection gp = new Selection();
gp.add(new JButton("Button"));
f.add(new JScrollPane(gp), BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}
});
}
Selection() {
this.setPreferredSize(new Dimension(WIDE, HIGH));
this.addMouseListener(new MouseHandler());
this.addMouseMotionListener(new MouseMotionHandler());
}
#Override
public void paintComponent(Graphics g) {
g.setColor(new Color(0x00f0f0f0));
g.fillRect(0, 0, getWidth(), getHeight());
for (Node n : nodes) {
n.draw(g);
}
if (selecting) {
g.setColor(Color.BLACK
);
((Graphics2D) g).setComposite(AlphaComposite.getInstance(rule, alpha));
g.fillRect(mouseRect.x, mouseRect.y,
mouseRect.width, mouseRect.height);
g.drawRect(mouseRect.x, mouseRect.y,
mouseRect.width, mouseRect.height);
}
}
int rule = AlphaComposite.SRC_OVER;
float alpha = 0.9F;
private class MouseHandler extends MouseAdapter {
#Override
public void mouseReleased(MouseEvent e) {
selecting = false;
mouseRect.setBounds(0, 0, 0, 0);
if (e.isPopupTrigger()) {
}
e.getComponent().repaint();
}
#Override
public void mousePressed(MouseEvent e) {
mousePt = e.getPoint();
Node.selectNone(nodes);
selecting = true;
e.getComponent().repaint();
}
}
private class MouseMotionHandler extends MouseMotionAdapter {
Point delta = new Point();
#Override
public void mouseDragged(MouseEvent e) {
if (selecting) {
mouseRect.setBounds(
Math.min(mousePt.x, e.getX()),
Math.min(mousePt.y, e.getY()),
Math.abs(mousePt.x - e.getX()),
Math.abs(mousePt.y - e.getY()));
} else {
delta.setLocation(
e.getX() - mousePt.x,
e.getY() - mousePt.y);
mousePt = e.getPoint();
}
e.getComponent().repaint();
}
}
/** A Node represents a node in a graph. */
private static class Node {
private Color color;
private boolean selected = false;
private Rectangle b = new Rectangle();
/** Draw this node. */
public void draw(Graphics g) {
g.setColor(this.color);
if (selected) {
g.setColor(Color.darkGray);
g.drawRect(b.x, b.y, b.width, b.height);
}
}
/** Mark this node as slected. */
public void setSelected(boolean selected) {
this.selected = selected;
}
/** Select no nodes. */
public static void selectNone(List<Node> list) {
for (Node n : list) {
n.setSelected(false);
}
}
}
#Override
public void stateChanged(ChangeEvent arg0) {
// TODO Auto-generated method stub
}
}
I think that can be a problem with place where I implement my button. I use eclipse SDK.
Can you help me?

Change your main to this. The reason is that you are setting alpha to < 1 for the entire panel and so the button is getting lighter shade. Simply move the button out of the panel and you are set.
public static void main(String[] args) throws Exception {
EventQueue.invokeLater(new Runnable() {
public void run() {
JFrame f = new JFrame("GraphPanel");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new BorderLayout());
JButton button = new JButton("Button");
panel.add(button, BorderLayout.PAGE_START);
Selection gp = new Selection();
panel.add(gp, BorderLayout.CENTER);
f.add(new JScrollPane(panel), BorderLayout.CENTER);
f.pack();
f.setVisible(true);
}
});
}