I have problem with displaying the image on JPanel when I rescaled the image according to the size of the JPanel. The image did not appear.
public class createGUII extends JFrame{
String [] background = {"c1.jpg","c2.jpg","c3.jpg","c4.jpg"};
ArrayList<String> bgPicturesFiles = new ArrayList<String>(Arrays.asList(background));
JPanel panel;
ImagePanel imgBg;
public createGUII(){
GridBagLayout m = new GridBagLayout();
Container c = getContentPane();
c.setLayout (m);
GridBagConstraints con = new GridBagConstraints();
//Panel for background
panel = new JPanel();
panel.setSize(600, 600);
con = new GridBagConstraints();
con.anchor=GridBagConstraints.CENTER;
con.gridy = 1; con.gridx = 0;
con.gridwidth = 1; con.gridheight = 1;
m.setConstraints(panel, con);
c.add(panel);
//randomized the image files
Random r = new Random();
int random = r.nextInt(bgPicturesFiles.size());
//rescale the image according to the size of the JPanel
imgBg = new ImagePanel(new ImageIcon(bgPicturesFiles.get(random)).getImage().getScaledInstance(panel.getHeight(), panel.getWidth(),Image.SCALE_SMOOTH));
panel.add(imgBg);
setResizable(false);
setVisible(true);
setExtendedState(getExtendedState()|JFrame.MAXIMIZED_BOTH);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new createGUII();
}
});
}
}
class ImagePanel extends JPanel {
private Image img;
public ImagePanel(String img) {
this(new ImageIcon(img).getImage());
}
public ImagePanel(Image img) {
this.img = img;
Dimension size = new Dimension(img.getWidth(null), img.getHeight(null));
setPreferredSize(size);
setMinimumSize(size);
setMaximumSize(size);
setSize(size);
setLayout(null);
}
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, null);
}
}
Have a look at this: JPanel background image, JPanel with background image, with other panels overlayed
The second link mentions that you have to do some custom painting for scaling. This is a problem. I wouldn't scale the image every single time in the paintComponent method, but do it once if the width and height have been changed since the last call, and in that case, recreate a BufferedImage containing the image which you blit every single time before calling the superclass paintComponent, scaled up to the right size (use something like Image scaling does not work when original image height & width is smaller the scaling height & width). I can see an issue where it might try to fill the panel with a colour when you call the superclass paintComponent method, but you'll have to experiment.
The problem is that in Java images get loaded asynchronously. There are several issues with the above code because of that:
The image doesn't get loaded, so it's dimensions are (-1, -1). Thus, ImagePanel's size is invalid
Even if the dimensions get set manually (i.e. changing it to new Dimension(600, 600)), the image itself may not be loaded.
JFrame resizing is disabled. If you allow it, you would be able to get the image drawn with the above code by artificially making Swing load the image when the JFrame is resized
To ensure loading, add the following:
new ImageIcon(img).getImage();
after this.img = img; in ImagePanel's constructor.
Note that this is partially a hack - I'm not a GUI expert, but I get the idea the above could be written much better. Maybe somebody else might be able to shed more light.
Here are some links that might be helpful:
http://www.exampledepot.com/egs/java.awt.image/Image2Buf.html
http://webcache.googleusercontent.com/search?q=cache:Ho0L4KoL44AJ:java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html+java+getscaledinstance&cd=1&hl=en&ct=clnk&gl=us&client=ubuntu (yes, it's from Google cache, the original link doesn't work...)
Hope this helps.
I don't see where you're actually reading the image, as suggested in this example.
Addendum: I've added an example of scaling. See also Don't Use getScaledInstance() and The Perils of Image.getScaledInstance().
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Image;
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;
/** #see http://stackoverflow.com/questions/4170463 */
public class LoadImage extends JPanel {
private Image image;
public LoadImage() {
super(new GridLayout());
try {
image = ImageIO.read(new File("image.jpg"));
} catch (IOException ex) {
ex.printStackTrace(System.err);
}
int w = image.getWidth(null) / 2;
int h = image.getHeight(null) / 2;
this.add(new JLabel(new ImageIcon(
image.getScaledInstance(w, h, Image.SCALE_SMOOTH))));
}
private void display() {
JFrame f = new JFrame("LoadImage");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new LoadImage().display();
}
});
}
}
Here is a link that should help. However I found a way that better suited the problem I had this was what I found, and the following is what I took from that.
I hope this helps.
Container con = getContentPane();
final String backgroundPath = "C:\\background.jpg";
ImageIcon imh = new ImageIcon(backgroundPath);
setSize(imh.getIconWidth(), imh.getIconHeight());
JPanel pnlBackground = new JPanel()
{
public void paintComponent(Graphics g)
{
Image img = new ImageIcon(backgroundPath).getImage();
g.drawImage(img, 0, 0, null);
}
};
con.add(pnlBackground);
pnlBackground.setBounds(0, 0, imh.getIconWidth(), imh.getIconHeight());
Related
I started programming in SWING class recently and I try to set Image (like Space) and on it image(like spaceShip) like background. I
would love for you to help me,
Here is my code
public class SpaceWar {
static JFrame frame = new JFrame("Space War");
static JPanel panel = new JPanel();
public static void main(String[] args) {
new SpaceWar();
//frame.setResizable(false);
frame.setVisible(true);
}
public SpaceWar() {
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
Dimension size
= Toolkit.getDefaultToolkit().getScreenSize();
frame.setPreferredSize(size);
frame.setLayout(null);
panel.setLayout(null);
panel.setBounds(frame.getPreferredSize().width/4,0,
frame.getPreferredSize().width/2,frame.getPreferredSize().height);
frame.add(panel);
frame.add(new Background());
spaceShip sp1 = new spaceShip();
panel.setBackground(Color.black);
panel.add(sp1);
System.out.println(panel.getPreferredSize().width);
}
}
class spaceShip extends JLabel{
static ImageIcon img = new ImageIcon("spaceShip.png");
public spaceShip(){
sizeIcon(100,100,img);
setIcon(img);
}
public static ImageIcon sizeIcon(int w,int h,ImageIcon image1){
Image image = image1.getImage(); // transform it
Image newimg = image.getScaledInstance(w,h, java.awt.Image.SCALE_SMOOTH); // scale it the smooth way
ImageIcon img1 = new ImageIcon(newimg); // transform it back
return img1;
}
}
class Background extends JPanel{
public void paint(Graphics g) { // paint() method
super.paint(g);
ImageIcon image = new ImageIcon("space.jpg");
Image bg = image.getImage();
g.drawImage(bg,0,0,null);
}
}
So, your "core" problem is the use of null layouts and a lack of understand of how components are sized and positioned. Having said that, if your aim is to make a game, this probably isn't the best approach anyway.
Instead, I'd focus on creating a "surface", onto which you can paint all your assets directly, this will give you much greater control.
Start by taking a look at Painting in AWT and Swing and Performing Custom Painting to get a better understanding how the paint system works and how you can work with it to perform custom painting.
I'd also avoid ImageIcon, it's not the best way to handle images, instead, take a look at ImageIO (Reading/Loading an Image), it will generate an IOException if the image can't be loaded and will return a fully realised image (unlike ImageIcon which off loads the image loading to a background thread).
For example...
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
public class MainPane extends JPanel {
private BufferedImage ufo;
private BufferedImage background;
private int horizontalPosition = 106;
public MainPane() throws IOException {
ufo = ImageIO.read(getClass().getResource("/images/ufo.png"));
background = ImageIO.read(getClass().getResource("/images/starfield.png"));
System.out.println("background = " + background);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
paintBackground(g2d);
paintUFO(g2d);
g2d.dispose();
}
protected void paintBackground(Graphics2D g2d) {
int x = (getWidth() - background.getWidth()) / 2;
int y = (getHeight() - background.getHeight()) / 2;
g2d.drawImage(background, x, y, this);
}
protected void paintUFO(Graphics2D g2d) {
int x = (getWidth() - ufo.getWidth()) / 2;
int y = (getHeight() - ufo.getHeight()) / 2;
g2d.drawImage(ufo, x, y, this);
}
}
}
The example makes use of embedded resources (something to read up on). Managing your assets this way will save you countless hours of wondering why they aren't loading/working. How you achieve this will come down to your IDE and build system, for example, Netbeans and Eclipse will allow you to add resources directly to the src directory, when you're not using maven.
At some point, you're going to want to learn about How to Use Swing Timers and How to Use Key Bindings
i am setting frame's background image when i run program my other components are invisible only image is visible in frame
class ImagePanel extends JComponent {
private Image image;
public ImagePanel(Image image) {
this.image = image;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
In the main class I call the above class as shown below:
BufferedImage myImage = ImageIO.read(new File("cal.jpg"));
frame.setContentPane(new ImagePanel(myImage));
You have this code:
BufferedImage myImage = ImageIO.read(new File("cal.jpg"));
frame.setContentPane(new ImagePanel(myImage));
but you appear to be creating the ImagePanel instance inline, and don't appear to be adding any components to this ImagePanel instance, so I'm not surprised that you're not seeing any components. You also don't seem to be adding any components to it in the ImagePanel constructor.
Consider adding components to the ImagePanel class within its constructor, or in the class that uses it, create an ImagePanel instance, assign it to a variable, add components to it, and then place it into the JFrame's contentPane.
Side recommendations:
Consider getting your image as a Jar resource and not as a File, since likely you will Jar the classes at some point, and if you continue using File, your image might not be reachable.
Make sure to give your ImagePanel a decent layout manager. I believe that JComponents use null layouts by default, something that you don't want to use.
For example, this worked for me:
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Image;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
public class TestImagePanel {
private static void createAndShowGui() {
String resource = "/imgFolder/PlanetEarth.jpg";
Image image = null;
try {
image = ImageIO.read(TestImagePanel.class.getResource(resource));
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
ImagePanel mainPanel = new ImagePanel(image);
mainPanel.setLayout(new FlowLayout());
mainPanel.add(new JButton("Fubars Rule!"));
JFrame frame = new JFrame("TestImagePanel");
frame.setDefaultCloseOperation(JFrame.DISPOSE_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();
}
});
}
}
#SuppressWarnings("serial")
class ImagePanel extends JComponent {
private Image image;
public ImagePanel(Image image) {
this.image = image;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
#Override
public Dimension getPreferredSize() {
Dimension superSize = super.getPreferredSize();
int w = image == null ? superSize.width : Math.max(superSize.width, image.getWidth(null));
int h = image == null ? superSize.height : Math.max(superSize.height, image.getHeight(null));
Dimension d = new Dimension(w, h);
return d;
}
}
and showed this GUI:
I'm trying to get some images to scale for a chess program I'm writing. I tried writing up a small program just to get a feel for scaling images and I ran into a problem with the image displaying. Basically the image will only display properly if that ImageIcon (icon) is there and it is above pawn in the code. If it doesn't exist, it is below pawn in the code, or the image sources are different pawn displays as a black square. If I don't try and scale pawn then the whole thing works just fine regardless of whether icon is there or not. This whole thing just really perplexes me because the only association pawn and icon have is that they share a source image. Can anyone shed some light on this?
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class resizeImg extends JFrame{
public void generateGui(){
JPanel mainPanel=new JPanel();
getContentPane().add(mainPanel);
JPanel main=new JPanel();
main.setBorder(BorderFactory.createLineBorder(new Color(0,0,0)));
main.setSize(400,400);
mainPanel.add(main);
mainPanel.setLayout(null);
ImageIcon icon=new ImageIcon(Toolkit.getDefaultToolkit().getImage("resources/pawn.jpg"));
//if you remove the above ImageIcon the image just displays as a black square
Image pawn=scale(Toolkit.getDefaultToolkit().getImage("resources/pawn.jpg"));
JLabel pawnContainer=new JLabel(new ImageIcon(pawn));
main.add(pawnContainer);
setSize(400,400);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public BufferedImage scale(Image i){
BufferedImage resized=new BufferedImage(50,50,BufferedImage.TYPE_INT_RGB);
Graphics2D g=resized.createGraphics();
g.drawImage(i,0,0,50,50,null);
g.dispose();
return resized;
}
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable(){
public void run(){
resizeImg imgObject=new resizeImg();
imgObject.generateGui();
imgObject.setVisible(true);
}
});
}
}
The original image loading code was designed to load to images over slow networks, so it uses a background thread to load the image. This means that when Toolkit.getImage returns, the image may not have actually begin loaded.
When you included the ImageIcon call, ImageIcon is using a MediaTracker to waitFor the image to become loaded. Because of the caching mechanism of Toolkit.getImage, repeated calls for the same image can use the cached image instead.
This is, also, why it's important to use an ImageObserver when painting images, but it may not help you in this case.
Instead, use ImageIO
public class Scale extends JFrame {
public void generateGui() {
JPanel main = new JPanel();
main.setBorder(BorderFactory.createLineBorder(new Color(0, 0, 0)));
main.setLayout(new BorderLayout());
try {
BufferedImage image = ImageIO.read(new File("path/to/image"));
Image pawn = scale(image);
JLabel pawnContainer = new JLabel(new ImageIcon(pawn));
main.add(pawnContainer);
} catch (IOException exp) {
exp.printStackTrace();
}
add(main);
setSize(400, 400);
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public BufferedImage scale(Image i) {
BufferedImage resized = new BufferedImage(50, 50, BufferedImage.TYPE_INT_RGB);
Graphics2D g = resized.createGraphics();
g.drawImage(i, 0, 0, 50, 50, this);
g.dispose();
return resized;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
Scale imgObject = new Scale();
imgObject.generateGui();
imgObject.setVisible(true);
}
});
}
}
I recently started with Java GUIs a few weeks ago and I have a difficulty with alignment.
Basically, I'm trying to have two Panels with a different background image (top Bar and content) and I want to align them one after another.
The problem is, that I can't use BorderLayout.NORTH and BorderLayout.SOUTH, because the background image loses his original size and gets very tiny.
How can I align them correctly, without losing the original size?
Here's my code:
package main;
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ImageTest {
public static void main(String[] args) {
ImageFrame frame = new ImageFrame("topBar.png", "contentImage.png");
frame.setSize(640,480);
frame.setVisible(true);
}
}
class ImagePanel extends JPanel {
private Image img;
public ImagePanel(String img) {
this(new ImageIcon(img).getImage());
}
public ImagePanel(Image img) {
this.img = img;
}
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, null);
}
}
class ImageFrame extends JFrame {
public ImageFrame(String topBar, String body) {
setLayout(new BorderLayout());
ImagePanel topPanel = new ImagePanel(topBar);
ImagePanel bodyPanel = new ImagePanel(body);
add(topPanel, BorderLayout.NORTH);
add(bodyPanel, BorderLayout.SOUTH);
pack();
}
}
There are a number of issues that popup out at me
You're not calling super.paintComponent. This is very important and can not be understated
You really should be using ImageIO to load your images. Ala from the fact it supports a wider range of image formats, it also loads images concurrent and throws useful exceptions when something goes wrong
You're not supplying any preferredSize values. This is used by the layout manager to decide how best to layout your component. Remember though, this are only hints and layout managers are well within there rights to ignore them
Check out Reading/Loading an Image for more details on ImageIO
..the background image loses his original size and gets very tiny.
That is because the preferred size for a panel is 0x0 until components are put in it.
There are at least two ways to solve this:
Add content to the panels.
Override getPreferredSize() to return the Dimension of the image.
The first is optimal, but I'll show how to do the 2nd (less code).
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ImageTest {
public static void main(String[] args) {
ImageFrame frame = new ImageFrame();
//frame.setSize(640,480);
frame.pack();
frame.setVisible(true);
}
}
class ImagePanel extends JPanel {
private Image img;
public ImagePanel(String img) {
this(new ImageIcon(img).getImage());
}
public ImagePanel(Image img) {
this.img = img;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
// a panel IS an ImageObserver, so use it here.
g.drawImage(img, 0, 0, this);
}
#Override
public Dimension getPreferredSize() {
int w = img.getWidth(this);
int h = img.getHeight(this);
return new Dimension(w,h);
}
}
class ImageFrame extends JFrame {
public ImageFrame() {
setLayout(new BorderLayout(2,2));
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
ImagePanel topPanel = new ImagePanel(new BufferedImage(200,20,BufferedImage.TYPE_INT_RGB));
ImagePanel bodyPanel = new ImagePanel(new BufferedImage(200,100,BufferedImage.TYPE_INT_RGB));
add(topPanel, BorderLayout.NORTH);
add(bodyPanel, BorderLayout.SOUTH);
pack();
}
}
Good day!
Is it possible to add a JPanel on top of a JLabel?
I would like my JFrame to have a background image and in order to this, i used this code (based from past stackoverflow answers):
setLocation(150,50);
setSize(700,650);
setVisible(true);
JLabel contentPane = new JLabel();
contentPane.setIcon(new ImageIcon("pics/b1.jpg"));
contentPane.setLayout( new BorderLayout());
setContentPane( contentPane );
Now my problem is, I cannot put a panel on my JFrame because of the JLabel background.
Please help.
Thanks.
To create a background image for a JFrame, I recommend that you draw the image in the paintComponent method of a JPanel, and then add this JPanel to the contentPane BorderLayout.CENTER which has it fill the contentPane. You may even want to set the JPanel's preferredSize to be that of the Image. Then you can add any components you'd like to the image panel, and don't have to worry about trying to add comopnents to a JLabel which seems bass ackwards to me.
For example here's a program that does this but slightly different. It creates an ImagePanel object, a JPanel that draws an image and sizes itself to the image and then places it in a JScrollPane which is then added to the contentPane, but you can just get rid of the JScrollPane and put your image JPanel directly in the contentPane instead:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;
public class BigDukeImage {
public static final String IMAGE_PATH = "http://" + "duke.kenai.com/nyanya/NyaNya.jpg";
private static final Dimension SCROLLPANE_SIZE = new Dimension(900, 700);
private static void createAndShowUI() {
Image image = null;
try {
URL url = new URL(IMAGE_PATH);
image = ImageIO.read(url);
// JLabel label = new JLabel(new ImageIcon(image));
ImagePanelA imagePanel = new ImagePanelA(image);
JScrollPane scrollpane = new JScrollPane();
// scrollpane.getViewport().add(label);
scrollpane.getViewport().add(imagePanel);
scrollpane.setPreferredSize(SCROLLPANE_SIZE);
JFrame frame = new JFrame("Big Duke Image");
frame.getContentPane().add(scrollpane);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
JScrollBar vertSBar = scrollpane.getVerticalScrollBar();
JScrollBar horzSBar = scrollpane.getHorizontalScrollBar();
vertSBar.setValue((vertSBar.getMaximum() - vertSBar.getVisibleAmount()) / 2);
horzSBar.setValue((horzSBar.getMaximum() - horzSBar.getVisibleAmount()) / 2);
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
#SuppressWarnings("serial")
class ImagePanelA extends JPanel {
private Image image;
public ImagePanelA(Image image) {
this.image = image;
setPreferredSize(new Dimension(image.getWidth(null), image.getHeight(null)));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image != null) {
g.drawImage(image, 0, 0, null);
}
}
}
You could use a JLayeredPane. This lets you add components to different layers and have them ontop of one another.
I cannot put a panel on my JFrame because of the JLabel background
Thats because a panel is opague so it paints over top of the label. You need to use:
panel.setOpaque( false );
sure..you can....Use NetBEans IDE to simplify tedious tasks like this by drag and drop and write the actual programming..