How can I implement Marquee effect in Java Swing
Here's an example using javax.swing.Timer.
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
/** #see http://stackoverflow.com/questions/3617326 */
public class MarqueeTest {
private void display() {
JFrame f = new JFrame("MarqueeTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
String s = "Tomorrow, and tomorrow, and tomorrow, "
+ "creeps in this petty pace from day to day, "
+ "to the last syllable of recorded time; ... "
+ "It is a tale told by an idiot, full of "
+ "sound and fury signifying nothing.";
MarqueePanel mp = new MarqueePanel(s, 32);
f.add(mp);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
mp.start();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new MarqueeTest().display();
}
});
}
}
/** Side-scroll n characters of s. */
class MarqueePanel extends JPanel implements ActionListener {
private static final int RATE = 12;
private final Timer timer = new Timer(1000 / RATE, this);
private final JLabel label = new JLabel();
private final String s;
private final int n;
private int index;
public MarqueePanel(String s, int n) {
if (s == null || n < 1) {
throw new IllegalArgumentException("Null string or n < 1");
}
StringBuilder sb = new StringBuilder(n);
for (int i = 0; i < n; i++) {
sb.append(' ');
}
this.s = sb + s + sb;
this.n = n;
label.setFont(new Font("Serif", Font.ITALIC, 36));
label.setText(sb.toString());
this.add(label);
}
public void start() {
timer.start();
}
public void stop() {
timer.stop();
}
#Override
public void actionPerformed(ActionEvent e) {
index++;
if (index > s.length() - n) {
index = 0;
}
label.setText(s.substring(index, index + n));
}
}
I know this is a late answer, but I just saw another question about a marquee that was closed because it was considered a duplicate of this answer.
So I thought I'd add my suggestion which takes a approach different from the other answers suggested here.
The MarqueePanel scrolls components on a panel not just text. So this allows you to take full advantage of any Swing component. A simple marquee can be used by adding a JLabel with text. A fancier marquee might use a JLabel with HTML so you can use different fonts and color for the text. You can even add a second component with an image.
Basic answer is you draw your text / graphic into a bitmap and then implement a component that paints the bitmap offset by some amount. Usually marquees / tickers scroll left so the offset increases which means the bitmap is painted at -offset. Your component runs a timer that fires periodically, incrementing the offset and invalidating itself so it repaints.
Things like wrapping are a little more complex to deal with but fairly straightforward. If the offset exceeds the bitmap width you reset it back to 0. If the offset + component width > bitmap width you paint the remainder of the component starting from the beginning of the bitmap.
The key to a decent ticker is to make the scrolling as smooth and as flicker free as possible. Therefore it may be necessary to consider double buffering the result, first painting the scrolling bit into a bitmap and then rendering that in one go rather than painting straight into the screen.
Here is some code that I threw together to get you started. I normally would take the ActionListener code and put that in some sort of MarqueeController class to keep this logic separate from the panel, but that's a different question about organizing the MVC architecture, and in a simple enough class like this it may not be so important.
There are also various animation libraries that would help you do this, but I don't normally like to include libraries into projects only to solve one problem like this.
public class MarqueePanel extends JPanel {
private JLabel textLabel;
private int panelLocation;
private ActionListener taskPerformer;
private boolean isRunning = false;
public static final int FRAMES_PER_SECOND = 24;
public static final int MOVEMENT_PER_FRAME = 5;
/**
* Class constructor creates a marquee panel.
*/
public MarqueePanel() {
this.setLayout(null);
this.textLabel = new JLabel("Scrolling Text Here");
this.panelLocation = 0;
this.taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
MarqueePanel.this.tickAnimation();
}
}
}
/**
* Starts the animation.
*/
public void start() {
this.isRunning = true;
this.tickAnimation();
}
/**
* Stops the animation.
*/
public void stop() {
this.isRunning = false;
}
/**
* Moves the label one frame to the left. If it's out of display range, move it back
* to the right, out of display range.
*/
private void tickAnimation() {
this.panelLocation -= MarqueePanel.MOVEMENT_PER_FRAME;
if (this.panelLocation < this.textLabel.getWidth())
this.panelLocaton = this.getWidth();
this.textLabel.setLocation(this.panelLocation, 0);
this.repaint();
if (this.isRunning) {
Timer t = new Timer(1000 / MarqueePanel.FRAMES_PER_SECOND, this.taskPerformer);
t.setRepeats(false);
t.start();
}
}
}
Add a JLabel to your frame or panel.
ScrollText s= new ScrollText("ello Everyone.");
jLabel3.add(s);
public class ScrollText extends JComponent {
private BufferedImage image;
private Dimension imageSize;
private volatile int currOffset;
private Thread internalThread;
private volatile boolean noStopRequested;
public ScrollText(String text) {
currOffset = 0;
buildImage(text);
setMinimumSize(imageSize);
setPreferredSize(imageSize);
setMaximumSize(imageSize);
setSize(imageSize);
noStopRequested = true;
Runnable r = new Runnable() {
public void run() {
try {
runWork();
} catch (Exception x) {
x.printStackTrace();
}
}
};
internalThread = new Thread(r, "ScrollText");
internalThread.start();
}
private void buildImage(String text) {
RenderingHints renderHints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
renderHints.put(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
BufferedImage scratchImage = new BufferedImage(1, 1,
BufferedImage.TYPE_INT_RGB);
Graphics2D scratchG2 = scratchImage.createGraphics();
scratchG2.setRenderingHints(renderHints);
Font font = new Font("Serif", Font.BOLD | Font.ITALIC, 24);
FontRenderContext frc = scratchG2.getFontRenderContext();
TextLayout tl = new TextLayout(text, font, frc);
Rectangle2D textBounds = tl.getBounds();
int textWidth = (int) Math.ceil(textBounds.getWidth());
int textHeight = (int) Math.ceil(textBounds.getHeight());
int horizontalPad = 600;
int verticalPad = 10;
imageSize = new Dimension(textWidth + horizontalPad, textHeight
+ verticalPad);
image = new BufferedImage(imageSize.width, imageSize.height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = image.createGraphics();
g2.setRenderingHints(renderHints);
int baselineOffset = (verticalPad / 2) - ((int) textBounds.getY());
g2.setColor(Color.BLACK);
g2.fillRect(0, 0, imageSize.width, imageSize.height);
g2.setColor(Color.GREEN);
tl.draw(g2, 0, baselineOffset);
// Free-up resources right away, but keep "image" for
// animation.
scratchG2.dispose();
scratchImage.flush();
g2.dispose();
}
public void paint(Graphics g) {
// Make sure to clip the edges, regardless of curr size
g.setClip(0, 0, imageSize.width, imageSize.height);
int localOffset = currOffset; // in case it changes
g.drawImage(image, -localOffset, 0, this);
g.drawImage(image, imageSize.width - localOffset, 0, this);
// draw outline
g.setColor(Color.black);
g.drawRect(0, 0, imageSize.width - 1, imageSize.height - 1);
}
private void runWork() {
while (noStopRequested) {
try {
Thread.sleep(10); // 10 frames per second
// adjust the scroll position
currOffset = (currOffset + 1) % imageSize.width;
// signal the event thread to call paint()
repaint();
} catch (InterruptedException x) {
Thread.currentThread().interrupt();
}
}
}
public void stopRequest() {
noStopRequested = false;
internalThread.interrupt();
}
public boolean isAlive() {
return internalThread.isAlive();
}
}
This is supposed to be an improvement of #camickr MarqueePanel. Please see above.
To map mouse events to the specific components added to MarqueePanel
Override add(Component comp) of MarqueePanel in order to direct all mouse events of the components
An issue here is what do do with the MouseEvents fired from the individual components.
My approach is to remove the mouse listeners form the components added and let the MarqueePanel redirect the event to the correct component.
In my case these components are supposed to be links.
#Override
public Component add(Component comp) {
comp = super.add(comp);
if(comp instanceof MouseListener)
comp.removeMouseListener((MouseListener)comp);
comp.addMouseListener(this);
return comp;
}
Then map the component x to a MarqueePanel x and finally the correct component
#Override
public void mouseClicked(MouseEvent e)
{
Component source = (Component)e.getSource();
int x = source.getX() + e.getX();
int y = source.getY();
MarqueePanel2 marqueePanel = (MarqueePanel2) ((JComponent)e.getSource()).getParent();
double x2 = marqueePanel.getWidth();
double x1 = Math.abs(marqueePanel.scrollOffset);
if(x >= x1 && x <= x2)
{
System.out.println("Bang " + x1);
Component componentAt = getComponentAt(x+marqueePanel.scrollOffset, y);
if(comp instanceof MouseListener)
((MouseListener) componentAt).mouseClicked(e);
System.out.println(componentAt.getName());
}
else
{
return;
}
//System.out.println(x);
}
Related
I'm new to Java, and I was assigned in my class to develop a code for the following question, I was only able to do the design, after that I didn't know how to continue adding the actions to every button.
This is the question:
https://www.chegg.com/homework-help/questions-and-answers/write-java-application-creates-frame-similar-one-shown--four-letter-word-shown-four-panels-q52352988
If anyone has ever solved it, please share it.
Thanks for help in advance!
Since this is homework, I'm not providing the entire code. I will provide snippets.
Here's the GUI I created. I wish I could show it as an animated GIF.
I added a stop button to stop the word rotation.
I wrote the code by breaking the problem down into smaller and smaller steps, then coding each of the steps. I ran many tests of the GUI before I finished it. Some of the tests failed, and I had to revise the code.
I wrote 6 classes. The main class created the JFrame, the letter panel group, and the control panel on the bottom. I wrote a LetterPanel class to create one letter panel. I wrote 3 actionListener classes, one for the JComboBox, one for the rotate button, and one for the stop button. I wrote an Animation class that rotates the letters every second.
Here are the colors I used to get the 4 shades of green.
Color[] colors = { new Color(50, 117, 1),
new Color(65, 159, 0), new Color(88, 201, 5),
new Color(107, 242, 2)
};
Setting up the main JPanel to hold the 4 LetterPanel objects was a bit tricky. Here's how I did it.
JPanel panel = new JPanel();
panel.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));
The LetterPanel class extended a JPanel and overrode the paintComponent method. First, I called the super.paintComponent method. Always call the super.paintComponent method first. Then, I painted the background color. Then, I painted the letter.
To paint the letter in each LetterPanel, I used the following code.
/**
* Draw a String centered in the middle of the panel.
*
* #param g2d The Graphics2D instance.
* #param text The String to draw.
* #param font The Font to draw with.
*/
public void drawCenteredString(Graphics2D g2d,
String text, Font font) {
FontMetrics metrics = g2d.getFontMetrics(font);
int x = (getWidth() - metrics.stringWidth(text)) / 2;
int y = ((getHeight() - metrics.getHeight()) / 2) +
metrics.getAscent();
g2d.setFont(font);
g2d.drawString(text, x, y);
}
The JComboBox actionListener gets the selected word from the JComboBox. The Oracle tutorial, How to Use Combo Boxes, tells you exactly how I set up the word JComboBox.
The rotate button actionListener checks if both JCheckBox fields are checked. Then it checks if neither JCheckBox field is checked. Finally, it starts an Animation thread.
The stop button stops the Animation thread.
The Animation thread rotates the word and pauses 1 second to allow you to see the rotation.
Here is the run loop.
#Override
public void run() {
while (running) {
updatePanel();
sleep(1000L);
if (leftSelected) {
word = rotateLeft(word);
} else {
word = rotateRight(word);
}
}
}
Here are my rotation methods.
private String rotateLeft(String word) {
return word.substring(1) + word.substring(0, 1);
}
private String rotateRight(String word) {
return word.substring(word.length() - 1) +
word.substring(0, word.length() - 1);
}
Edited to add;
I'd forgotten I'd answered this question. Enough time has passed so I'll post the entire application. I made the additional classes inner classes so I can post this code as one block.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class RotateWord implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new RotateWord());
}
private Animation animation;
private JCheckBox leftBox;
private JCheckBox rightBox;
private JComboBox<String> wordComboBox;
private JFrame frame;
private LetterPanel[] letterPanel;
private String word;
public RotateWord() {
this.word = "WORD";
}
#Override
public void run() {
frame = new JFrame("Rotate Word");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createWordPanel(word), BorderLayout.CENTER);
frame.add(createControlPanel(word),
BorderLayout.AFTER_LAST_LINE);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createWordPanel(String word) {
JPanel panel = new JPanel();
panel.setLayout(new FlowLayout(FlowLayout.CENTER, 0, 0));
Color[] colors = { new Color(50, 117, 1),
new Color(65, 159, 0), new Color(88, 201, 5),
new Color(107, 242, 2)
};
letterPanel = new LetterPanel[word.length()];
for (int i = 0; i < word.length(); i++) {
letterPanel[i] = new LetterPanel(colors[i],
word.charAt(i));
panel.add(letterPanel[i]);
}
return panel;
}
public void updateWordPanel(String word) {
for (int i = 0; i < word.length(); i++) {
letterPanel[i].setLetter(word.charAt(i));
letterPanel[i].repaint();
}
}
private JPanel createControlPanel(String word) {
JPanel panel = new JPanel();
String[] words = { "ABLE", "BATH", "EXIT", "WORD" };
wordComboBox = new JComboBox<>(words);
wordComboBox.setSelectedItem(word);
wordComboBox.addActionListener(new WordListener());
panel.add(wordComboBox);
leftBox = new JCheckBox("Left");
panel.add(leftBox);
rightBox = new JCheckBox("Right");
panel.add(rightBox);
JButton rotateButton = new JButton("Rotate");
rotateButton.addActionListener(new RotateListener());
panel.add(rotateButton);
JButton stopButton = new JButton("Stop");
stopButton.addActionListener(new StopListener());
panel.add(stopButton);
return panel;
}
public class LetterPanel extends JPanel {
private static final long serialVersionUID = 1L;
private char letter;
private Color backgroundColor;
private Font font;
public LetterPanel(Color backgroundColor, char letter) {
this.backgroundColor = backgroundColor;
this.letter = letter;
this.font = getFont().deriveFont(96f)
.deriveFont(Font.BOLD);
this.setPreferredSize(new Dimension(120, 200));
}
public void setLetter(char letter) {
this.letter = letter;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(backgroundColor);
g2d.fillRect(0, 0, getWidth(), getHeight());
g2d.setColor(Color.BLACK);
drawCenteredString(g2d, Character.toString(letter),
font);
}
/**
* Draw a String centered in the middle of the panel.
*
* #param g2d The Graphics2D instance.
* #param text The String to draw.
* #param font The Font to draw with.
*/
public void drawCenteredString(Graphics2D g2d,
String text, Font font) {
FontMetrics metrics = g2d.getFontMetrics(font);
int x = (getWidth() - metrics.stringWidth(text)) / 2;
int y = ((getHeight() - metrics.getHeight()) / 2) +
metrics.getAscent();
g2d.setFont(font);
g2d.drawString(text, x, y);
}
}
public class WordListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent event) {
word = (String) wordComboBox.getSelectedItem();
updateWordPanel(word);
}
}
public class RotateListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent event) {
boolean leftSelected = leftBox.isSelected();
boolean rightSelected = rightBox.isSelected();
if (leftSelected && rightSelected) {
word = "OOPS";
updateWordPanel(word);
return;
}
if (!leftSelected && !rightSelected) {
return;
}
word = (String) wordComboBox.getSelectedItem();
updateWordPanel(word);
animation = new Animation(leftSelected);
new Thread(animation).start();
}
}
public class StopListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent event) {
if (animation != null) {
animation.setRunning(false);
animation = null;
}
}
}
public class Animation implements Runnable {
private boolean leftSelected;
private volatile boolean running;
public Animation(boolean leftSelected) {
this.leftSelected = leftSelected;
this.running = true;
}
#Override
public void run() {
while (running) {
updatePanel();
sleep(1000L);
if (leftSelected) {
word = rotateLeft(word);
} else {
word = rotateRight(word);
}
}
}
public synchronized void setRunning(boolean running) {
this.running = running;
}
private String rotateLeft(String word) {
return word.substring(1) + word.substring(0, 1);
}
private String rotateRight(String word) {
return word.substring(word.length() - 1) +
word.substring(0, word.length() - 1);
}
private void updatePanel() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
updateWordPanel(word);
}
});
}
private void sleep(long duration) {
try {
Thread.sleep(duration);
} catch (InterruptedException e) {
// Deliberately left blank
}
}
}
}
in my application I have label which has a font size over 200. This label contains big up and down (irregular)gap. How can I remove it ?
This is my code:
package Core;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
public class LabelDemo extends JPanel {
public LabelDemo() {
super(new GridBagLayout());
JLabel label2;
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.gridy = 0;
// Create the other labels.
label2 = new JLabel("Text-Only Label");
label2.setBorder(BorderFactory.createTitledBorder("aaaaaaaa"));
label2.setFont(new Font("Verdana", Font.PLAIN, (int) 220));
// label2.setBorder(new EmptyBorder(-50, 0, 0, 0));
// Add the labels.
add(label2, c);
}
/**
* Create the GUI and show it. For thread safety, this method should be invoked from the event dispatch thread.
*/
private static void createAndShowGUI() {
// Create and set up the window.
JFrame frame = new JFrame("LabelDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Add content to the window.
frame.add(new LabelDemo());
// Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
// Schedule a job for the event dispatch thread:
// creating and showing this application's GUI.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
// Turn off metal's use of bold fonts
UIManager.put("swing.boldMetal", Boolean.FALSE);
createAndShowGUI();
}
});
}
}
I also try my last post: How to change gap in swing label and experiment with insets but this looks different in linux and windows
Is there some better way how to remove this gap ?
JDigit may give you some ideas:
It override's paintComponent() to down-sample a high-resolution BufferedImage and control the geometry.
It uses setBorderPainted(false) to set the borderPainted property.
It uses a FocusHandler for custom highlighting.
Addendum: As noted here, the underlying problem is the font's leading, defined in FontMetrics as being included in the font's height. As suggested in a comment by #Guillaume Polet, you can render the text wherever you want in your own JComponent. TextLayout, discussed here, can be used to calculate the bounds, as shown below.
Pros:
Absolute control over placement.
Geometry of TexteLayout bounds based on FontMetrics.
Cons:
No Icon support.
No HTML support.
Note that the JComponent authors "recommend that you put the component in a JPanel and set the border on the JPanel."
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**
* #see https://stackoverflow.com/a/16014525/230513
*/
public class UnleadedTest {
private static class Unleaded extends JComponent {
private Font font = new Font("Verdana", Font.PLAIN, 144);
private FontRenderContext frc = new FontRenderContext(null, true, true);
private String text;
private TextLayout layout;
private Rectangle r;
public Unleaded(String text) {
this.text = text;
calcBounds();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(r.width, r.height);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
calcBounds();
layout.draw(g2d, -r.x, -r.y);
}
private void calcBounds() {
layout = new TextLayout(text, font, frc);
r = layout.getPixelBounds(null, 0, 0);
}
}
private void display() {
JFrame f = new JFrame("Unleaded");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Unleaded label = new Unleaded("Unleaded");
JPanel panel = new JPanel();
panel.setBorder(BorderFactory.createTitledBorder("Title"));
panel.add(label);
f.add(panel);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new UnleadedTest().display();
}
});
}
}
The "right way" to do this would be to extend "BasicLabelUI" and override the "protected String layoutCL()" method. This is the method that is responsible for laying out everything inside the label and is called when the "getPreferredSize()" of the JLabel is called. So this method determines the height the component is going to be.
If you drill down deep enough you'll see that the height is determined by the following line in the SwingUtilities:1021 class (which is used by layoutCL):
textR.height = fm.getHeight();
So the label is not causing the white space, the font is. The label just conforms to what the FontMetrics object says is the maximum height of the font for that size.
The easiest way would probably be to cheat; Force the size calculation to do something it shouldn't. Below is your example with a custom LabelUI component which you can experiment on. For example if you force the variable to 'dy' to '-40' the text will be at the top. If you want to make something more durable you could check all the leters in the string of the label, measure their maximum height and use that in the layoutCL method. But thats more work obviously.
package Core;
import sun.swing.SwingUtilities2;
import javax.swing.*;
import javax.swing.plaf.LabelUI;
import javax.swing.plaf.basic.BasicLabelUI;
import javax.swing.text.View;
import java.awt.*;
public class LabelDemo extends JPanel {
public LabelDemo() {
super(new GridBagLayout());
JLabel label2;
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.gridy = 0;
// Create the other labels.
label2 = new JLabel("Text-Only Label");
label2.setVerticalAlignment(SwingUtilities.TOP);
label2.setVerticalTextPosition(SwingUtilities.TOP);
label2.setUI(SkinnyLabelUI.createUI(label2));
label2.setBorder(BorderFactory.createTitledBorder("aaaaaaaa"));
label2.setFont(new Font("Verdana", Font.PLAIN, (int) 220));
// label2.setBorder(new EmptyBorder(-50, 0, 0, 0));
// Add the labels.
add(label2, c);
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event dispatch thread.
*/
private static void createAndShowGUI() {
// Create and set up the window.
JFrame frame = new JFrame("LabelDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Add content to the window.
frame.add(new LabelDemo());
// Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
// Schedule a job for the event dispatch thread:
// creating and showing this application's GUI.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
// Turn off metal's use of bold fonts
UIManager.put("swing.boldMetal", Boolean.FALSE);
createAndShowGUI();
}
});
}
private static class SkinnyLabelUI extends BasicLabelUI {
private static final SkinnyLabelUI labelUI = new SkinnyLabelUI();
public static LabelUI createUI(JComponent c) {
return labelUI;
}
protected String layoutCL(
JLabel label,
FontMetrics fm,
String text,
Icon icon,
Rectangle viewR,
Rectangle iconR,
Rectangle textR) {
int verticalAlignment = label.getVerticalAlignment();
int horizontalAlignment = label.getHorizontalAlignment();
int verticalTextPosition = label.getVerticalTextPosition();
int horizontalTextPosition = label.getHorizontalTextPosition();
if (icon != null) {
iconR.width = icon.getIconWidth();
iconR.height = icon.getIconHeight();
} else {
iconR.width = iconR.height = 0;
}
/* Initialize the text bounds rectangle textR. If a null
* or and empty String was specified we substitute "" here
* and use 0,0,0,0 for textR.
*/
boolean textIsEmpty = (text == null) || text.equals("");
int lsb = 0;
int rsb = 0;
/* Unless both text and icon are non-null, we effectively ignore
* the value of textIconGap.
*/
int gap;
View v;
if (textIsEmpty) {
textR.width = textR.height = 0;
text = "";
gap = 0;
} else {
int availTextWidth;
gap = (icon == null) ? 0 : label.getIconTextGap();
if (horizontalTextPosition == SwingUtilities.CENTER) {
availTextWidth = viewR.width;
} else {
availTextWidth = viewR.width - (iconR.width + gap);
}
v = (label != null) ? (View) label.getClientProperty("html") : null;
if (v != null) {
textR.width = Math.min(availTextWidth,
(int) v.getPreferredSpan(View.X_AXIS));
textR.height = (int) v.getPreferredSpan(View.Y_AXIS);
} else {
textR.width = SwingUtilities2.stringWidth(label, fm, text);
lsb = SwingUtilities2.getLeftSideBearing(label, fm, text);
if (lsb < 0) {
// If lsb is negative, add it to the width and later
// adjust the x location. This gives more space than is
// actually needed.
// This is done like this for two reasons:
// 1. If we set the width to the actual bounds all
// callers would have to account for negative lsb
// (pref size calculations ONLY look at width of
// textR)
// 2. You can do a drawString at the returned location
// and the text won't be clipped.
textR.width -= lsb;
}
if (textR.width > availTextWidth) {
text = SwingUtilities2.clipString(label, fm, text,
availTextWidth);
textR.width = SwingUtilities2.stringWidth(label, fm, text);
}
textR.height = fm.getHeight();
System.out.println("font height: " + textR.height);
}
}
/* Compute textR.x,y given the verticalTextPosition and
* horizontalTextPosition properties
*/
if (verticalTextPosition == SwingUtilities.TOP) {
if (horizontalTextPosition != SwingUtilities.CENTER) {
textR.y = 0;
} else {
textR.y = -(textR.height + gap);
}
} else if (verticalTextPosition == SwingUtilities.CENTER) {
textR.y = (iconR.height / 2) - (textR.height / 2);
} else { // (verticalTextPosition == BOTTOM)
if (horizontalTextPosition != SwingUtilities.CENTER) {
textR.y = iconR.height - textR.height;
} else {
textR.y = (iconR.height + gap);
}
}
if (horizontalTextPosition == SwingUtilities.LEFT) {
textR.x = -(textR.width + gap);
} else if (horizontalTextPosition == SwingUtilities.CENTER) {
textR.x = (iconR.width / 2) - (textR.width / 2);
} else { // (horizontalTextPosition == RIGHT)
textR.x = (iconR.width + gap);
}
// WARNING: DefaultTreeCellEditor uses a shortened version of
// this algorithm to position it's Icon. If you change how this
// is calculated, be sure and update DefaultTreeCellEditor too.
/* labelR is the rectangle that contains iconR and textR.
* Move it to its proper position given the labelAlignment
* properties.
*
* To avoid actually allocating a Rectangle, Rectangle.union
* has been inlined below.
*/
int labelR_x = Math.min(iconR.x, textR.x);
int labelR_width = Math.max(iconR.x + iconR.width,
textR.x + textR.width) - labelR_x;
int labelR_y = Math.min(iconR.y, textR.y);
int labelR_height = Math.max(iconR.y + iconR.height,
textR.y + textR.height) - labelR_y;
int dx, dy;
if (verticalAlignment == SwingUtilities.TOP) {
dy = viewR.y - labelR_y;
} else if (verticalAlignment == SwingUtilities.CENTER) {
dy = (viewR.y + (viewR.height / 2)) - (labelR_y + (labelR_height / 2));
} else { // (verticalAlignment == BOTTOM)
dy = (viewR.y + viewR.height) - (labelR_y + labelR_height);
}
if (horizontalAlignment == SwingUtilities.LEFT) {
dx = viewR.x - labelR_x;
} else if (horizontalAlignment == SwingUtilities.RIGHT) {
dx = (viewR.x + viewR.width) - (labelR_x + labelR_width);
} else { // (horizontalAlignment == CENTER)
dx = (viewR.x + (viewR.width / 2))
- (labelR_x + (labelR_width / 2));
}
/* Translate textR and glypyR by dx,dy.
*/
textR.x += dx;
textR.y += dy;
iconR.x += dx;
iconR.y += dy;
if (lsb < 0) {
// lsb is negative. Shift the x location so that the text is
// visually drawn at the right location.
textR.x -= lsb;
textR.width += lsb;
}
if (rsb > 0) {
textR.width -= rsb;
}
return text;
}
}
}
changing the border offset might help:
int OFFSET_TOP=50,OFFSET_BOTTOM=50;
label.setBorder(new TitledBorder(TITLE){
#Override
public Insets getBorderInsets(Component c, Insets insets){
return new Insets(insets.top - OFFSET_TOP, insets.left, insets.bottom - OFFSET_BOTTOM, insets.right);
}
});
Sorry guys, I deleted my APPLES and CATS example :) Here's the updated version of my question!
I'm losing my sanity here. I need someone who can enlighten me. I've tried a couple of times explaining my problem here. Hopefully, this time, my question will be easier to understand.
Basically I have this frame, and there's an image displayed. There is a JList on the right, and there is another panel for JLabels at the bottom. Here's a screencap of my frame.
When I click on the image, a JOptionPane pops out, like so. And I enter my input. My JList is an ArrayList, so everything I input is added to the JList and the JPanel at the bottom.
Now, when I hover on the the part where I clicked, you noticed that the square disappeared). It only appears when I click the image, and when I hover the label at the bottom. My labels, as of now are LOLZ NOSE and INPUT HERE.
What I want to do is when I hover on the label, for example INPUT HERE, it shows the square again, featuring the part where I clicked. My problem now is when I click on NOSE, which is supposed to be showing a square on the nose part and a the name NOSE with black bg, IT IS NOT SHOWING. Also, only the last label's square is shown, disregarding the other labels' position clicked.
How do I get a label to remember the position of the click I make? People said I should use ArrayLists or HashCodes however I have no idea how to implement them. Thank you to anyone who can help.
Edit: I've already done the rectangle, btw. It's showing only for the last label inputted. Here are some of the code snippets requested!
How I'm setting the text on JLabel and updating the JList:
public void updateLabel(){
StringBuilder text = new StringBuilder(); //creates empty builder, capacity 16
for(Object s: tagModel.toArray()) //returns an array containing the elements of the tagModel
text.append(" " + s);
repaint();
hoverLabel.setText(text.toString()); //returns a String
hoverLabel.addMouseMotionListener(this);
hoverPanel.add(hoverLabel);
}
My mouseListener upon click:
#Override
public void mouseClicked(MouseEvent event) {
// TODO Auto-generated method stub
x = event.getX();
y = event.getY();
isRectPresent = true;
repaint();
input = JOptionPane.showInputDialog("Enter tag name:");
if((input != null) && !input.isEmpty()){
tagModel.addElement(input);
}
}
My mouseMotionListener upon hovering:
#Override
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
xpos = e.getX(); //gets where the mouse moved
ypos = e.getY();
//checks if the mouse is inside the bounds of the rectangle
if (xpos > x && xpos < x + 100 && ypos > y && ypos < y + 100)
isRectPresent = false;
if(e.getSource() == hoverLabel){
isRectPresent = true;
repaint();
}
repaint();
}
How I'm painting:
public void paintComponent(Graphics g){
Graphics2D g2 = (Graphics2D) g;
g2.drawImage(image, 0, 0, null);
if(image != null && isRectPresent){
Stroke stroke = g2.getStroke();
g2.setStroke(new BasicStroke(4));
g2.setColor(Color.WHITE);
g2.drawRect(x-50, y-50, 100, 100);
g2.setStroke(stroke);
}else{
if(xpos > x && xpos < x + 100 && ypos > y && ypos < y + 100){
g.setColor(Color.BLACK);
g.fillRect(x-50, y-50, 100, 25);
g.setColor(Color.WHITE);
g.setFont(new Font("Tahoma", Font.BOLD, 12));
g.drawString(input, x-30, y-30);
}
}
}
If you want me to add some more snippets, just tell me! :)
You should create a HashMap, say something like:
Map linkSet = new HashMap();
And whenever you click on the drawing and create a label, add the JLabel and the point on the image to the set using the put method with the JLabel as the key and the Point as the value. Then in the JLabel's MouseMotionListener, use your label as a key and obtain the corresponding point from the set using the map's get(...) method.
edit:
Corrected as per alicedimarco's comment. Again, thanks!
edit 2
I think you want again to use a Map. If you have a Map, you can have it retrieve the Point of interest from the JLabel's or the JList's String, and then pass this Point to the class that's drawing the image and let it use the Point to draw a rectangle. For instance you could give the image drawing class a Point field called displayPoint, and a method called setDisplayPoint(Point p). It can be as simple as this:
public void setDisplayPoint(Point p) {
this.displayPoint = p;
repaint();
}
and assuming that the object of interest is centered at that point, use the displayPoint in the paintComponent method:
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// draw image
if (img != null) {
g.drawImage(img, X_SHIFT, Y_SHIFT, null);
}
// if displayPoint not null, draw the surrounding rectangle
if (displayPoint != null) {
g.setColor(RECT_COLOR);
int x = displayPoint.x - RECT_WIDTH / 2;
int y = displayPoint.y - RECT_WIDTH / 2;
int width = RECT_WIDTH;
int height = RECT_WIDTH;
g.drawRect(x, y, width, height);
}
}
edit 3:
To get mouse clicks, it's quite easy, simply add a MouseListener to the component that holds the image:
// !! added
imgRect.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
imgMousePressed(e);
}
});
And in your code that is called from this mouse listener, use a JOptionPane to get the user's choice of tag name, and add the resulting String to both the listDataModel so that it is seen in the JList and also in the stringPointMap together with the Point obtained from the MouseEvent so that you can map the String to the Point and be able to retrieve it:
// !! added
private void imgMousePressed(MouseEvent e) {
String result = JOptionPane.showInputDialog(this,
"Please enter name for this point on image:");
if (result != null) {
stringPointMap.put(result, e.getPoint());
listDataModel.addElement(result);
}
}
That's it.
Then putting it all together:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class ImageRectMain extends JPanel {
private ImageRect imgRect;
private DefaultListModel listDataModel = new DefaultListModel();
private JList list = new JList(listDataModel);
private Map<String, Point> stringPointMap = new HashMap<String, Point>();
public ImageRectMain() {
String nose = "Nose";
String ear = "Ear";
String rightEye = "Right Eye";
String leftEye = "Left Eye";
listDataModel.addElement(ear);
listDataModel.addElement(nose);
listDataModel.addElement(rightEye);
listDataModel.addElement(leftEye);
stringPointMap.put(nose, new Point(480, 500));
stringPointMap.put(ear, new Point(270, 230));
stringPointMap.put(rightEye, new Point(380, 390));
stringPointMap.put(leftEye, new Point(662, 440));
MouseAdapter listMouseAdapter = new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent e) {
listMouseMoved(e);
}
#Override
public void mouseExited(MouseEvent e) {
listMouseExited(e);
}
};
list.addMouseMotionListener(listMouseAdapter);
list.addMouseListener(listMouseAdapter);
try {
imgRect = new ImageRect();
// !! added
imgRect.addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
imgMousePressed(e);
}
});
JPanel eastPanel = new JPanel();
eastPanel.setLayout(new BoxLayout(eastPanel, BoxLayout.PAGE_AXIS));
eastPanel.add(new JLabel("You have tagged the following:"));
eastPanel.add(new JScrollPane(list));
eastPanel.add(Box.createVerticalGlue());
eastPanel.add(Box.createVerticalGlue());
eastPanel.add(Box.createVerticalGlue());
eastPanel.add(Box.createVerticalGlue());
setLayout(new BorderLayout());
add(imgRect, BorderLayout.CENTER);
add(eastPanel, BorderLayout.EAST);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// !! added
private void imgMousePressed(MouseEvent e) {
String result = JOptionPane.showInputDialog(this,
"Please enter name for this point on image:");
if (result != null) {
stringPointMap.put(result, e.getPoint());
listDataModel.addElement(result);
}
}
private void listMouseExited(MouseEvent e) {
imgRect.setDisplayPoint(null);
}
private void listMouseMoved(MouseEvent e) {
int index = list.locationToIndex(e.getPoint());
Object value = listDataModel.get(index);
if (value != null) {
Point point = stringPointMap.get(value.toString());
if (point != null) {
imgRect.setDisplayPoint(point);
}
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("ImageRectMain");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ImageRectMain());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class ImageRect extends JPanel {
public static final String IMAGE_PATH = "http://i.stack.imgur.com/7oNzg.jpg";
private static final int DEFAULT_W = 687;
private static final int DEFAULT_H = 636;
private static final int X_SHIFT = -6;
private static final int Y_SHIFT = -26;
private static final Color RECT_COLOR = Color.pink;
private static final int RECT_WIDTH = 40;
private BufferedImage img;
private Point displayPoint = null;
public ImageRect() throws MalformedURLException, IOException {
img = ImageIO.read(new URL(IMAGE_PATH));
}
public void setDisplayPoint(Point p) {
this.displayPoint = p;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, X_SHIFT, Y_SHIFT, null);
}
if (displayPoint != null) {
g.setColor(RECT_COLOR);
int x = displayPoint.x - RECT_WIDTH / 2;
int y = displayPoint.y - RECT_WIDTH / 2;
int width = RECT_WIDTH;
int height = RECT_WIDTH;
g.drawRect(x, y, width, height);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(DEFAULT_W, DEFAULT_H);
}
}
One nice feature of a JList is that you can story any object in it. You're not limited to strings. When objects are stored in JLists, swing will call the object's toString() method, and display it in the list.
Knowing this, you can now write your own class that stores the name of your selection label and the coordinates of the box. This object's toString() method will return the name of the label, which will make the right thing appear in the JList.
Then, in the selection event handler for the JList, you can get your custom object out, and retrieve the box coordinates stored in it, and draw them on the screen. No need to fuss with other containers (although knowing how to use them is a good thing to).
Ok, Create a class like this...
public class MyLabel {
private int x;
private int y;
private String text;
public MyLabel (String text, int x, int y) {
this.text = text;
// assign x and y too...
}
#Override
public String toString() {
return label;
}
public int getX() {
return x;
}
// similar function to getY()
}
The class above overrides toString(), so when you put it in a JList, it will use the call to toString() to determine what to display, and since this toString implementation returns the label name you'll see that in the list.
And add those into your JList instead of Strings. Then at some point in your code you'll do something like this...
// this is pseudocode, method names may not be correct...
MyLabel ml = (MyLabel)jList.getSelectedItem();
int x = ml.getX();
int y = ml.getY();
// draw the box...
Hope that helps.
I've been searching for a way to draw a black-and-white array on screen. It's a simple array, just 20x20. What I plan to do is to draw on an array with the mouse so that each pixel "toggles" from black to white and back when clicked, then pass the array as a set of booleans (or integers) to another function. Currently I'm using Swing. I do remember to have used Swing for drawing on a canvas, but I still can't find the actual usage. Should I use a canvas, or instead rely on JToggleButtons?
You can simply use a JFrame (or other Swing component) and override the paint(Graphics) method to draw a representation of the boolean matrix (note that in the case of a lightweight component such as JPanel you should override paintComponent(Graphics). This will give you the click-and-drag capability you require (which is very difficult to achieve using a grid of individual Swing components).
As other people have commented, AWT Canvas doesn't give you anything not provided by Swing components and you'll see in the example below that I've used the createBufferStrategy method also present on JFrame to ensure a non-flicker display.
Note that my example is fairly simple in that it toggles every pixel you drag across rather than the click operation establishing whether you're in "paint" mode or "erase" mode and then exclusively applying black or white pixels for the duration of the drag.
public class Grid extends JFrame {
private static final int SCALE = 10; // 1 boolean value == 10 x 10 pixels.
private static final int SIZE = 20;
private boolean[][] matrix = new boolean[SIZE][SIZE];
private boolean painting;
private int lastX = -1;
private int lastY = -1;
public Grid() throws HeadlessException {
setPreferredSize(new Dimension(SIZE * SCALE, SIZE * SCALE));
setResizable(false);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setBackground(Color.WHITE);
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
painting = true;
tryAdjustValue(e.getPoint());
}
public void mouseReleased(MouseEvent e) {
painting = false;
lastX = -1;
lastY = -1;
}
});
addMouseMotionListener(new MouseMotionListener() {
public void mouseDragged(MouseEvent e) {
tryAdjustValue(e.getPoint());
}
public void mouseMoved(MouseEvent e) {
tryAdjustValue(e.getPoint());
}
});
}
private void tryAdjustValue(Point pt) {
int newX = pt.x / SCALE;
int newY = pt.y / SCALE;
if (painting && isInRange(newX) && isInRange(newY) && (newX != lastX || newY != lastY)) {
// Only invert "pixel" if we're currently in painting mode, both array indices are valid
// and we're not attempting to adjust the same "pixel" as before (important for drag operations).
matrix[newX][newY] = !matrix[newX][newY];
lastX = newX;
lastY = newY;
repaint();
}
}
private boolean isInRange(int val) {
return val >= 0 && val < SIZE;
}
public void paint(Graphics g) {
super.paint(g);
for (int x=0; x<SIZE; ++x) {
for (int y=0; y<SIZE; ++y) {
if (matrix[x][y]) {
g.fillRect(x * SCALE, y * SCALE, SCALE, SCALE);
}
}
}
}
public static void main(String[] args) {
Grid grid = new Grid();
grid.pack();
grid.setLocationRelativeTo(null);
grid.createBufferStrategy(2);
grid.setVisible(true);
}
}
Why not a simple 20 x 20 grid of JPanel held in a GridLayout(20, 20), and flip the panel's background color if clicked via a MouseListener's mousePressed method. You could hold the panels in a 2D array and query their background color whenever the need arises.
You could also use JLabels for this, but you'd have to remember to turn their opaque properties to true. A JButton would work as well or a JToggleButton, ... the options are almost limitless. I do not recommend though that you use AWT (Canvas) as their's no need to step backwards in functionality since Swing handles this so well.
If you get stuck on this, why not come back and show us your code and we'll better be able to give you more specific help.
Another way to solve this is to use a single JPanel and override its paintComponent method. You could give it an int[][] array to serve as its model, and then in the paintComponent method draw rectangles of whatever color desired based on the state of the model. Then give it a MouseListener that changes the state of the model and calls repaint.
e.g.,
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class BlackWhiteGridPanel extends JPanel {
// can have multiple colors if desired
// public static final Color[] COLORS = {Color.black, Color.red, Color.blue, Color.white};
public static final Color[] COLORS = {Color.black, Color.white};
public static final int SIDE = 20;
private static final int BWG_WIDTH = 400;
private static final int BWG_HEIGHT = BWG_WIDTH;
private int[][] model = new int[SIDE][SIDE]; // filled with 0's.
public BlackWhiteGridPanel() {
addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
myMousePressed(e);
}
});
}
private void myMousePressed(MouseEvent e) {
// find relative position of mouse press on grid.
int i = (e.getX() * SIDE) / getWidth();
int j = (e.getY() * SIDE) / getHeight();
int value = model[i][j];
// the model can only hold states allowed by the COLORS array.
// So if only two colors, then value can only be 0 or 1.
value = (value + 1) % COLORS.length;
model[i][j] = value;
repaint();
}
public int[][] getModel() {
// return a copy of model so as not to risk corruption from outside classes
int[][] copy = new int[model.length][model[0].length];
for (int i = 0; i < copy.length; i++) {
System.arraycopy(model[i], 0, copy[i], 0, model[i].length);
}
return copy;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int width = getWidth();
int ht = getHeight();
for (int i = 0; i < model.length; i++) {
for (int j = 0; j < model[i].length; j++) {
Color c = COLORS[model[i][j]];
g.setColor(c);
int x = (i * width) / SIDE;
int y = (j * ht) / SIDE;
int w = ((i + 1) * width) / SIDE - x;
int h = ((j + 1) * ht) / SIDE - y;
g.fillRect(x, y, w, h);
}
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(BWG_WIDTH, BWG_HEIGHT);
}
private static void createAndShowGui() {
BlackWhiteGridPanel mainPanel = new BlackWhiteGridPanel();
JFrame frame = new JFrame("BlackWhiteGrid");
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 have displayed an image(ball) inside the JApplet, now I want the image to move in a vertical way (up and down). The problem is I don't know how to do it.
Could someone has an idea about this matter?
You need to set the position of that image to some calculated value (means you caculate the vertical position using time, speed and maybe other restrictions).
How you'd set that position depends on how you draw the image.
Example, based on drawing in the applet's (or a nested component's) paint(Graphics g) method:
//first calculate the y-position
int yPos += timeSinceLastPaint * speed; //increment the position
if( (speed > 0 && yPos > someMaxY) || (speed < 0 && yPos <0 ) ) {
speed *= -1; //if the position has reached the bottom (max y) or the top invert the direction
}
//in your paint(Graphics g) method:
g.drawImage(image, yPos, x, null);
Then you'd have to constantly repaint the applet.
More information on animations in applets can be found here: http://download.oracle.com/javase/tutorial/uiswing/components/applet.html
another example for javax.swing.Timer with moving Ojbects created by paintComponent(Graphics g), and I have lots of Start, not some blurred Mikado :-)
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer;
public class AnimationBackground {
private Random random = new Random();
private JFrame frame = new JFrame("Animation Background");
private final MyJPanel panel = new MyJPanel();
private JLabel label = new JLabel("This is a Starry background.", JLabel.CENTER);
private JPanel stopPanel = new JPanel();
private JPanel startPanel = new JPanel();
public AnimationBackground() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
panel.setBackground(Color.BLACK);
for (int i = 0; i < 50; i++) {
Star star = new Star(new Point(random.nextInt(490), random.nextInt(490)));
star.setColor(new Color(100 + random.nextInt(155), 100 + random.nextInt(155), 100 + random.nextInt(155)));
star.setxIncr(-3 + random.nextInt(7));
star.setyIncr(-3 + random.nextInt(7));
panel.add(star);
}
panel.setLayout(new GridLayout(10, 1));
label.setForeground(Color.WHITE);
panel.add(label);
stopPanel.setOpaque(false);
stopPanel.add(new JButton(new AbstractAction("Stop this madness!!") {
private static final long serialVersionUID = 1L;
#Override
public void actionPerformed(ActionEvent e) {
panel.stopAnimation();
}
}));
panel.add(stopPanel);
startPanel.setOpaque(false);
startPanel.add(new JButton(new AbstractAction("Start moving...") {
private static final long serialVersionUID = 1L;
#Override
public void actionPerformed(ActionEvent e) {
panel.startAnimation();
}
}));
panel.add(startPanel);
frame.add(panel);
frame.pack();
frame.setLocation(150, 150);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
AnimationBackground aBg = new AnimationBackground();
}
});
}
private class Star extends Polygon {
private static final long serialVersionUID = 1L;
private Point location = null;
private Color color = Color.YELLOW;
private int xIncr, yIncr;
static final int WIDTH = 500, HEIGHT = 500;
Star(Point location) {
int x = location.x;
int y = location.y;
this.location = location;
this.addPoint(x, y + 8);
this.addPoint(x + 8, y + 8);
this.addPoint(x + 11, y);
this.addPoint(x + 14, y + 8);
this.addPoint(x + 22, y + 8);
this.addPoint(x + 17, y + 12);
this.addPoint(x + 21, y + 20);
this.addPoint(x + 11, y + 14);
this.addPoint(x + 3, y + 20);
this.addPoint(x + 6, y + 12);
}
public void setColor(Color color) {
this.color = color;
}
public void move() {
if (location.x < 0 || location.x > WIDTH) {
xIncr = -xIncr;
}
if (location.y < 0 || location.y > WIDTH) {
yIncr = -yIncr;
}
translate(xIncr, yIncr);
location.setLocation(location.x + xIncr, location.y + yIncr);
}
public void setxIncr(int xIncr) {
this.xIncr = xIncr;
}
public void setyIncr(int yIncr) {
this.yIncr = yIncr;
}
public Color getColor() {
return color;
}
}
private class MyJPanel extends JPanel {
private static final long serialVersionUID = 1L;
private ArrayList<Star> stars = new ArrayList<Star>();
private Timer timer = new Timer(20, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
for (Star star : stars) {
star.move();
}
repaint();
}
});
public void stopAnimation() {
if (timer.isRunning()) {
timer.stop();
}
}
public void startAnimation() {
if (!timer.isRunning()) {
timer.start();
}
}
#Override
public void addNotify() {
super.addNotify();
timer.start();
}
#Override
public void removeNotify() {
super.removeNotify();
timer.stop();
}
MyJPanel() {
this.setPreferredSize(new Dimension(512, 512));
}
public void add(Star star) {
stars.add(star);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
((Graphics2D) g).setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
for (Star star : stars) {
g.setColor(star.getColor());
g.fillPolygon(star);
}
}
}
}
How to move the image inside the JApplet ..?
Pretty much exactly the same way you might do it in a JFrame, JComponent or JPanel or...
Or to put that another way, nothing to do with applets and everything to do with Graphics2D. For more details, see the 2D Graphics Trail of the Java Tutorial.
When you've figured how to move an image and paint it to a Graphics2D, implement that logic in a JComponent or JPanel's paintComponent(Graphics) method and drop the component with moving image into a JApplet or JFrame (or a JPanel etc.).
For the animation side of it, use a javax.swing.Timer as seen in this example. This example does not extend any component. Instead, it creates a BufferedImage and adds it to a JLabel that is displayed to the user. When the timer fires, the code grabs the Graphics object of the image, and proceeds from there to draw the bouncing lines.
import java.awt.image.BufferedImage;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.*;
import javax.swing.*;
import java.util.Random;
class LineAnimator {
public static void main(String[] args) {
final int w = 640;
final int h = 480;
final RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON
);
hints.put(
RenderingHints.KEY_ALPHA_INTERPOLATION,
RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY
);
final BufferedImage bi = new BufferedImage(w,h, BufferedImage.TYPE_INT_ARGB);
final JLabel l = new JLabel(new ImageIcon(bi));
final BouncingLine[] lines = new BouncingLine[100];
int factor = 1;
for (int ii=0; ii<lines.length; ii++) {
lines[ii] = new BouncingLine(w*factor,h*factor);
}
final Font font = new Font("Arial", Font.BOLD, 30);
ActionListener al = new ActionListener() {
int count = 0;
long lastTime;
String fps = "";
private final BasicStroke stroke = new BasicStroke(6);
public void actionPerformed(ActionEvent ae) {
count++;
Graphics2D g = bi.createGraphics();
g.setRenderingHints(hints);
g.setColor(new Color(55,12,59));
g.fillRect(0,0,w,h);
g.setStroke(stroke);
for (int ii=0; ii<lines.length; ii++) {
lines[ii].move();
lines[ii].paint(g);
}
if ( System.currentTimeMillis()-lastTime>1000 ) {
lastTime = System.currentTimeMillis();
fps = count + " FPS";
count = 0;
}
g.setColor(Color.YELLOW);
g.setFont(font);
g.drawString(fps,5,h-5);
l.repaint();
g.dispose();
}
};
Timer timer = new Timer(25,al);
timer.start();
JOptionPane.showMessageDialog(null, l);
//System.exit(0);
timer.stop();
}
}
class BouncingLine {
private final Color color;
private static final Random random = new Random();
Line2D line;
int w;
int h;
int x1;
int y1;
int x2;
int y2;
BouncingLine(int w, int h) {
line = new Line2D.Double(random.nextInt(w),random.nextInt(h),random.nextInt(w),random.nextInt(h));
this.w = w;
this.h = h;
this.color = new Color(
random.nextInt(255)
,random.nextInt(255)
,random.nextInt(255)
,64+random.nextInt(128)
);
x1 = (random.nextBoolean() ? 1 : -1);
y1 = (random.nextBoolean() ? 1 : -1);
x2 = -x1;
y2 = -y1;
}
public void move() {
int tx1 = 0;
if (line.getX1()+x1>0 && line.getX1()+x1<w) {
tx1 = (int)line.getX1()+x1;
} else {
x1 = -x1;
tx1 = (int)line.getX1()+x1;
}
int ty1 = 0;
if (line.getY1()+y1>0 && line.getY1()+y1<h) {
ty1 = (int)line.getY1()+y1;
} else {
y1 = -y1;
ty1 = (int)line.getY1()+y1;
}
int tx2 = 0;
if (line.getX2()+x2>0 && line.getX2()+x2<w) {
tx2 = (int)line.getX2()+x2;
} else {
x2 = -x2;
tx2 = (int)line.getX2()+x2;
}
int ty2 = 0;
if (line.getY2()+y2>0 && line.getY2()+y2<h) {
ty2 = (int)line.getY2()+y2;
} else {
y2 = -y2;
ty2 = (int)line.getY2()+y2;
}
line.setLine(tx1,ty1,tx2,ty2);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D)g;
g2.setColor(color);
//line.set
g2.draw(line);
}
}
Update 1
I want to do it in JApplet(1) using the image(2), is it possible(3)?
The examples by mKorbel and myself feature either an image in a JLabel or custom rendering in a JPanel. In our case, we added the components to a JOptionPane & a JFrame. Either example could be just as easily added to a JApplet, or a JDialog, or as part of another panel, or.. See the Laying Out Components Within a Container lesson & Using Top-Level Containers in the Java Tutorial for more details.
Instead of the stars or lines in our examples, ..paint your image. My example goes so far as to demonstrate how to get the position to bounce around within the bounds of the container.
Sure it is possible, but "Batteries not included". Our intention is to give you some ideas that you can then adapt to your bouncing ball applet. I doubt anyone is going to create an example for you, using balls, in an applet. Though if you post an SSCCE that shows your intent and what you tried, I (and others) would often run with that source. If you want more specific answers, ask a more specific SSCCE. ;)
I want to do it in JApplet.
Why not both? You can have a hybrid application/applet as shown in this animation.