Develop Reference

Brightness implementation for JPanel in Swing

I want to create brightness functionality in Swing. JPanel and its component's brightness level will be adjust in this functionality.
To achieve this I used JLayeredPane and added JPanel as BrightNessPanel on the top of my JPanel called MainPanel. I am giving brightness effect by changing the opacity of BrightNessPanel. This will simulate Brightness effect for my MainPanel.
Now problem is that, I am not able to click the buttons present on MainPanel because of layer of BrightNessPanel.
How do I pass through clicks from BrightNessPanel to the buttons present on MainPanel??

You might be able to make use the JLayer API which allows you to perform painting operations ontop of other components.
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLayer;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.plaf.LayerUI;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
TestPane testPane = new TestPane();
BrightnessLayerUI layerUI = new BrightnessLayerUI();
JLayer<JComponent> layer = new JLayer<>(testPane, layerUI);
JSlider slider = new JSlider(0, 100);
slider.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
int value = slider.getValue();
float brightness = (100 - value) / 100f;
layerUI.setBrightness(brightness);
testPane.repaint();
}
});
slider.setValue(100);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(layer);
frame.add(slider, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
add(new JTextField(10), gbc);
add(new JButton("Hello"), gbc);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.dispose();
}
}
public class BrightnessLayerUI extends LayerUI<JComponent> {
private float brightness = 0f;
public void setBrightness(float brightness) {
this.brightness = brightness;
}
public float getBrightness() {
return brightness;
}
#Override
public void paint(Graphics g, JComponent c) {
super.paint(g, c);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(c.getBackground());
g2d.setComposite(AlphaComposite.SrcOver.derive(getBrightness()));
g2d.fillRect(0, 0, c.getWidth(), c.getHeight());
g2d.dispose();
}
}
}
One of the advantages of this is you could actually introduce a "brightness" algorithm, rather than faking it, by using a backing buffer, which is demonstrated the link above (this use to to blur the UI)

Is it possible to set a background image inside JTextArea (including JScrollPane) not all the frame window? [duplicate]

This question already has answers here:
Inserting an image under a JTextArea
(2 answers)
Closed 8 years ago.
I want to set background in JTextArea (having transparency), but I don't have any idea. Maybe it's not very important, but I just want have characteristically program. Please help.
This part of code, I create JTextArea.
notatnik_k = new JTextArea();
JScrollPane scrollPane2 = new JScrollPane(notatnik_k);
scrollPane2.setBounds(20,30, 263,200);
notatnik_k.setEditable(false);
add(scrollPane2);
This photo showing my problem:
Is there a simply way, to do it?

You will need to extend your JTextArea class and create a setBackground(Image image) method. This method would set a field to the image you want to use and then invoke the the repaint method (this.repaint()).
You should then override the paintComponent(Graphics) method to paint the component with the image you set using setBackground(Image image).

I found here on the site this sample of code, and I did a little change but I have one error and don't know why it's incorrect? It's shows error: "The method setBackgroundImage(Image) is undefined for the type JTextArea"
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class BackgroundDemo {
public JTextArea notatnik;
private static void createAndShowUI() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
final JFrame frame = new JFrame("BackgroundDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel buttonsPanel = new JPanel();
final JTextArea notatnik = new JTextArea();
JScrollPane scrollPane1 = new JScrollPane(notatnik);
scrollPane1.setBounds(20,270, 380,110);
JButton loadButton = new JButton("Set background");
buttonsPanel.add(loadButton);
loadButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JFileChooser fc = new JFileChooser(System.getProperty("user.home"));
int returnVal = fc.showOpenDialog(frame);
if (returnVal == JFileChooser.APPROVE_OPTION) {
try {
Image image = ImageIO.read(fc.getSelectedFile());
if (image != null)
notatnik.setBackgroundImage(image);
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
});
JPanel content = new JPanel(new BorderLayout());
content.add(buttonsPanel, BorderLayout.SOUTH);
frame.add(scrollPane1);
frame.add(content);
frame.setSize(new Dimension(800, 500));
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
static class MyTextArea extends JTextArea {
private Image backgroundImage;
public MyTextArea() {
super();
setOpaque(false);
}
public void setBackgroundImage(Image image) {
this.backgroundImage = image;
this.repaint();
}
#Override
protected void paintComponent(Graphics g) {
g.setColor(getBackground());
g.fillRect(0, 0, getWidth(), getHeight());
if (backgroundImage != null) {
g.drawImage(backgroundImage, 0, 0, this);
}
super.paintComponent(g);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}

On using Nimbus look and feel, JButton vanishes totally in a JFrame if there is a background image

I have a JFrame. In that i have used:
JTabbed panes.
JButton.
background images in a Jlabel which is added in JPanel.
Nimbus look and feel.
My problem is that whenever i use Nimbus look and feel the JButton vanishes only if there is a background image added. But this doesn't happen with other look and feel. Can anyone help me in getting the button visible?
Here is my code:
import javax.swing.ImageIcon;
import javax.swing.JTabbedPane;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.UIManager.LookAndFeelInfo;
import java.awt.*;
import java.awt.event.*;
class ImageTest
{
JTabbedPane tp;
JLabel lab1;
JPanel welcome;
JFrame frame;
ImageIcon image2;
JButton b1;
public void createUI()
{
frame=new JFrame("JTabbedPane Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b1=new JButton();
welcome= new JPanel(null);
welcome.setPreferredSize(new Dimension(1366,786));
ImageIcon icon = new ImageIcon(ImageTest.class.getResource("icloud.jpg"));
tp=new JTabbedPane();
Container pane = frame.getContentPane();
pane.add(tp);
tp.addTab("Welcome", welcome);
lab1=new JLabel();
lab1.setIcon(icon);
b1.setBounds(100,100,100,100);
lab1.setBounds(0,0,1500,700);
welcome.add(lab1);
welcome.add(b1);
b1.setVisible(true);
frame.setSize(500,500);
frame.setVisible(true);
frame.setTitle("I-Cloud");
}
public static void main(String[] args)
{
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
}
ImageTest w = new ImageTest();
w.createUI();
}
}
EDIT:
import javax.swing.ImageIcon;
import javax.swing.JTabbedPane;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.UIManager.LookAndFeelInfo;
import java.awt.*;
import java.awt.event.*;
class ImageTest
{
JTabbedPane tp;
JLabel lab1;
JPanel welcome,w;
JFrame frame;
ImageIcon image2;
JButton b1;
public void createUI()
{
frame=new JFrame("JTabbedPane Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
b1=new JButton();
welcome= new JPanel(new GridLayout(1,1,15,15));
w=new JPanel (new GridLayout(1, 1, 15, 15));
welcome.setPreferredSize(new Dimension(1366,786));
ImageIcon icon = new ImageIcon(ImageTest.class.getResource("icloud.jpg"));
tp=new JTabbedPane();
Container pane = frame.getContentPane();
pane.add(tp);
lab1=new JLabel();
lab1.setIcon(icon);
w.setOpaque(false);
w.add(b1);
b1.setVisible(true);
welcome.add(lab1);
welcome.add(w);
tp.addTab("Welcome", welcome);
frame.setSize(500,500);
frame.pack();
frame.setVisible(true);
frame.setTitle("I-Cloud");
}
public static void main(String[] args)
{
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
}
ImageTest w = new ImageTest();
w.createUI();
}
}
Thanks.

Your use of Swing GUI is out of kilter by use of null layouts and then adding one component on top of another, essentially covering up one of the components (the JButton) with another (the JLabel with the image).
Don't use null layout like you're doing. While to a newbie using null layout and setBounds seems the best way to create complex GUI's, the more you deal with Swing GUI creation, the more you will find that doing this will put your GUI in a straight-jacket, painting it in a very tight corner and making it very hard to extend or enhance. Just don't do this.
Don't add one component on top of another in the same container.
Instead give your JLabel with the image a layout manager.
Then add the JButton to the JLabel.
Then add the JLabel to the JTabbedPane.
Edit
Your latest edit did not use the JLabel as the container as suggested above. So if you use a separate container, then the button and the label will be shown side by side. To solve this, you either need to give the JLabel a layout manager, and then add the button to it as suggested above, or draw directly in a JPanel's paintComponent(...) method, and add the button to the JPanel.
For an example of the latter:
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
public class MyImageTest extends JPanel {
// public static final String SPEC = "https://duke.kenai.com/SunRIP/.Midsize/SunRIP.jpg.png";
public static final String SPEC = "http://upload.wikimedia.org/wikipedia/commons/3/37/"
+ "Mandel_zoom_14_satellite_julia_island.jpg";
private static final int PREF_H = 786;
private static final int GAP = 100;
private BufferedImage img;
public MyImageTest() {
try {
URL imgUrl = new URL(SPEC);
img = ImageIO.read(imgUrl);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
setLayout(new FlowLayout(FlowLayout.LEADING));
setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
JButton b = new JButton();
b.setPreferredSize(new Dimension(GAP, GAP));
add(b);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, getWidth(), getHeight(), this);
}
}
#Override
public Dimension getPreferredSize() {
if (img == null) {
return super.getPreferredSize();
} else {
int width = (img.getWidth() * PREF_H) / img.getHeight();
return new Dimension(width, PREF_H);
// return new Dimension(img.getWidth(), img.getHeight());
}
}
private static void createAndShowGui() {
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
MyImageTest mainPanel = new MyImageTest();
JFrame frame = new JFrame("MyImageTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

I think setting a background image in JLabel and then adding buttons even after adding containers is a very complex issue. Believe me tried it and it was a very complex task. you can do it by directly drawing as Hovercraft suggested, but remember you would get not so much good image quality with that method. :-|

JLabel unusable from other class

I got a problem with two problematics classes. One for drawing things, and other for implementing pan and zoom onto the previously drawn objects.
Imagine my interface as only two spitted panels, one empty(top) and one with a slider(bot):
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import java.awt.BorderLayout;
import javax.swing.JSplitPane;
import javax.swing.JPanel;
import javax.swing.BoxLayout;
import javax.swing.JLabel;
import javax.swing.JSlider;
import java.awt.FlowLayout;
public class Interface {
private JFrame mainFrame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {Interface window = new Interface();window.mainFrame.setVisible(true);
} catch (Exception e) { e.printStackTrace();}
}
});
}
public Interface() {initialize();}
private void initialize() {
mainFrame = new JFrame();
mainFrame.setTitle("LXView");
mainFrame.setMinimumSize(new Dimension(800, 600));
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainFrame.setExtendedState(mainFrame.getExtendedState()| JFrame.MAXIMIZED_BOTH);
mainFrame.getContentPane().setBackground(Color.WHITE);
mainFrame.getContentPane().setLayout(new BorderLayout(0, 0));
JSplitPane splitPane = new JSplitPane();
splitPane.setOrientation(JSplitPane.VERTICAL_SPLIT);
splitPane.setOneTouchExpandable(true);
splitPane.setBackground(Color.WHITE);
mainFrame.getContentPane().add(splitPane, BorderLayout.CENTER);
splitPane.setResizeWeight(0.99);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setEnabled(false);
splitPane.setLeftComponent(scrollPane);
Render topPane = new Render();
scrollPane.setViewportView(topPane);
topPane.setLayout(new BoxLayout(topPane, BoxLayout.X_AXIS));
JPanel botPane = new JPanel();
splitPane.setRightComponent(botPane);
botPane.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
JLabel zoomLevel = new JLabel("Zoom level:");
botPane.add(zoomLevel);
JSlider slider = new JSlider(JSlider.HORIZONTAL, 25, 100, 100);
slider.setMajorTickSpacing(15);
slider.setMinorTickSpacing(5);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.setPreferredSize(new Dimension(600,40));
botPane.add(slider);
PanAndZoom zoomer=new PanAndZoom(topPane.getLabel());
slider.addChangeListener(zoomer);
}
The top panel uses the render class which was made to draw graphics. Simplifying:
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Render extends JPanel {
JLabel envContainer;
Render() {
super();
ImageIcon imageIcon = new ImageIcon("/path/to/img1");
JLabel envContainer = new JLabel(imageIcon);
super.add(envContainer);
}
#Override
public void paint(Graphics g) {
super.paint(g);
/*Render stuff*/
}
public JLabel getLabel() {
return envContainer;
}
}
And the third class which is giving me the trouble, listens on the slider and sets the JLabel icon according to it:
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class PanAndZoom implements ChangeListener {
private JLabel label;
private BufferedImage image;
public PanAndZoom(JLabel lab){
this.label=lab;
try {
image = ImageIO.read(new File("/path/to/img1"));
} catch (IOException e) {
e.printStackTrace();
}
label.setIcon(new ImageIcon("/path/to/img2"));//To test another img. It gives runtime errors.
}
public void stateChanged(ChangeEvent e) {
int value = ((JSlider) e.getSource()).getValue();
double scale = value / 100.0;
BufferedImage scaled = getScaledImage(scale); // It also gives runtime errors.
System.out.println("Scale:"+scale+" Value:"+value);
label.setIcon(new ImageIcon(scaled));
label.revalidate();
}
private BufferedImage getScaledImage(double scale) {
int w = (int) (scale * image.getWidth());
int h = (int) (scale * image.getHeight());
BufferedImage bi = new BufferedImage(w, h, image.getType());
Graphics2D g2 = bi.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BICUBIC);
AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
g2.drawRenderedImage(image, at);
g2.dispose();
return bi;
}
}
Why cant i use the JLabel if it was successfully returned by the getLabel method?

You're local version of envContainer in class Render's constructor is overriding the class instance envContainer.
public class Render extends JPanel {
JLabel envContainer; //<---- class instance
Render() {
super();
ImageIcon imageIcon = new ImageIcon("/path/to/img1");
JLabel envContainer = new JLabel(imageIcon); //<---- overriden by local instance, hence class instance remains null
super.add(envContainer);
}
My guess is that you didn't mean to make it a local version since you're not using it within the constructor for anything. Make the following change to your Render constructor.
Render() {
..
this.envContainer = new JLabel(imageIcon);
...
}

JLabel text position

I´m new with JLabel, i wonder if it's possible to set the text in a coordenate specific (x,y) over an image.
Like this:
So the text is "HI"
label.setText("HI");
label.setIcon(icon);
I'm trying to say that label contains an image and a text but i want to locate it in a specific position like the image above.
I don't want to use label.setHorizontalTextPosition(i);
or setVerticalTextPosition(i);
Sorry for my bad english
Thanks in advance ^ ^

By overriding the paintComponent method, text can be drawn in any position.
JLabel label = new JLabel(icon) {
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawString("Hi", 10, 10); //these are x and y positions
}
};

There are any number of, reasonable, ways to do it.
However, you should avoid using null layouts, pixel perfect layouts are an illusion within modern ui design. There are too many factors which affect the individual size of components, none of which you can control. Swing was designed to work with layout managers at the core, discarding these will lead to no end of issues and problems that you will spend more and more time trying to rectify
GridBagLayout and GridBagConstraints#insets
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
}
public class TestPane extends JPanel {
public TestPane() throws IOException {
setLayout(new GridBagLayout());
BufferedImage img = ImageIO.read(...);
JLabel background = new JLabel(new ImageIcon(img));
background.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.insets = new Insets(1, 46, 9, 0);
gbc.anchor = GridBagConstraints.SOUTH;
gbc.weighty = 1;
JLabel message = new JLabel("Go that way!");
message.setVerticalAlignment(JLabel.BOTTOM);
background.add(message, gbc);
add(background);
}
}
}
Graphics2D
You could paint the text directly onto the image, but as you can see, it becomes considerably more complex
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
}
public class TestPane extends JPanel {
public TestPane() throws IOException {
JLabel background = new JLabel();
BufferedImage img = ImageIO.read(...);
Graphics2D g2d = img.createGraphics();
g2d.setFont(background.getFont());
String text = "Go that way!";
FontMetrics fm = g2d.getFontMetrics();
int x = 46 + (((img.getWidth() - 46) - fm.stringWidth(text)) / 2);
int y = (((img.getHeight() - fm.getHeight())) + fm.getAscent()) - 9;
g2d.setColor(Color.BLACK);
g2d.drawString(text, x, y);
g2d.dispose();
background.setIcon(new ImageIcon(img));
add(background);
}
}
}

You can follow this Example, also take a look on setLocation() method for Components like JLabel, also try to use Layouts to manage better the position for each Component.
This guy also work with location with JLabel, you can see how he does the work and apply it in your project.
Example
JLabel label = new JLabel("Hi");
panel.add(label);
//This is to get the width and height
Dimension size = label.getPreferredSize();
//You can change 100(x) and 100(y) for your likes, so you can put that JLabel wherever you want
label.setBounds(100, 100, size.width, size.height);
You'll have to know what x and what y you want to put the JLabel right there.
If you want to do that, just do what tong1 did, but showing the x and y to know where exactly you want it.
Create a Container
Container container= getContentPane();
Add the JLabel on it
container.add(label);
Add an MouseListener() to get the x and y
container.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e){
//x and y are ints.
x = e.getX();
y = e.getY();
label.setBounds(x,y,150,50);
}
});