Adding Scaled BufferedImage to ContentPane

[switch]

I'm having a problem adding the background image to the contentPane. I was using ImageIcon but was using a pre-sized background images. I've since learned how to resize the image so I can use it on different screensizes, but I haven't been able to add the image to the contentPane. I have been able to add it to the JFrame, but I'm using JInternalframes, so adding the background to the JFrame isn't the correct way to go about this. Any suggestions?

// ImagePanel
class ImagePanel extends JPanel {
        
        private BufferedImage image;
                
        public ImagePanel() {
            try {
                file = new File("background.jpg");
                //get operating system and path to image file
                nameOS = System.getProperty("os.name").toLowerCase();
                if(nameOS.indexOf("win") >= 0){
                    String path = file.getAbsolutePath();
                    String newpath = path.replace('\\', '/');
                    imagepath = newpath.replace("C:/", "/");
                }else if(nameOS.indexOf("mac") >= 0){
                    String path = file.getAbsolutePath();
                    imagepath = path.replace("~/", "/");
                }
                image = ImageIO.read(new File(imagepath));
            } catch (IOException ioe) {ioe.getCause();}
        }
        
        @Override
        public void paintComponent(Graphics g) {
            scaledImage = image.getScaledInstance(getWidth(), getHeight(), Image.SCALE_DEFAULT);
            g.drawImage(scaledImage, 0, 0, null);
        }
    }

// part of JMenu
if(!exists){
            //send the user a message about the desktopPane image
            JOptionPane.showMessageDialog(frame, "Can't find " + filename + "! Painting background light gray...", "Error",
                                          JOptionPane.ERROR_MESSAGE);
            //initialize desktopPane
            desktopPane = new JDesktopPane();
            desktopPane.setBackground(Color.LIGHT_GRAY);
            frame.setContentPane(desktopPane);
        }else if(exists){
            //initialize desktopPane
            desktopPane = new JDesktopPane();
            frame.setContentPane(desktopPane);
            //get background image
            frame.getContentPane().add(new ImagePanel());
        }

[Fubarable]

You could always make the JLabel that holds the ImageIcon the contentPane. Just be sure to give it a decent layout manager, and be sure that it is set to be opaque.

[Fubarable]

Or you could use a JPanel and draw the BufferedImage in the JPanel's paintComponent method. Either way could work.

[DarrylBurke]

I'm using JInternalframes, so adding the background to the JFrame isn't the correct way to go about this.

You can do custom painting in a JDesktopPane too -- it's the same approach, just override paintComponent(...)

db

[switch]

Thanks for your help. I have tried these things you have suggested but nothing is working. If I comment out //scaledImage = img.blah,,, and change scaledImage to img on the next line, it will put the "huge" image on the content pane. But, because I've changed the name of img to scaledImage, Java ignores this line of code. I'm not a student, and have been learning Java on my own. I took an intro course a few years ago online, but the cost of the next course has doubled + a dollar since, so I'm trying to learn intermediate Java by using the Internet. My understanding is still a little fuzzy. Learning by example is my best option. I don't program for a living. This program is just a study guide for the three classes of Amateur Radio Operating License Exams. I hope that asking for an example is "not asking too much." Any help is appreciated. Thanks again.

Yours Truly,
switch

[Fubarable]

Create and post an SSCCE and we'll be in a much better position to help you.

[switch]

Let me explain a little further. What I've done is made two different sized background images. One is backgroundW.jpg (W for windows) and the other is backgroundM.jpg (M for mac), and by retrieving the operating system (windows or macintosh) I use the appropriate file so the image is displayed on my HP laptop and on my iMac. But, if I were to send this program to a friend to use on their computer, I would have to make a different image sized to their computers screen size, or make one huge image and have the program re-size the image according to the the screen size of the computer that the program is running on. That's what I'm trying to do. As you know, there's more than one way to skin a cat, but I think that the best way to write this program is to use one image and have the program re-size the image accordingly. Does this make sense?

73 = Best Regards (--... ...--)
switch

[switch]

Then I will post an SSCCE! Thanks...

[DarrylBurke]

You don't need to create a scaled instance of the image. You can use the overload of Graphics#drawImage(...) that take a width and height.

db

[switch]

Add the image file to the folder containing all folders for your program build. If you want to run the program from the *.jar file add the image file to the folder with the *.jar file.

import java.awt.*;
import java.io.File;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.io.IOException;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;

/**
 *
 * @author switch
 * Date: January 24, 2012
 */
public class ResizeImageProblem extends JFrame implements ActionListener, InternalFrameListener {
    
    private File file;
    private JFrame frame;
    private JMenu techMenu;
    private Image scaledImage;
    private JInternalFrame techFrame;
    private JDesktopPane desktopPane;  
    private JMenuItem openTech, quitTech;
    private String filename, imagepath, nameOS;
        
    //class required for setting the ContentPane image
    class ImagePanel extends JPanel {
        
        private BufferedImage image;
                        
        public ImagePanel() {
            
            try {
                //get operating system and path to path to image file
                    nameOS = System.getProperty("os.name").toLowerCase();
                    if(nameOS.indexOf("win") >= 0){
                        String path = file.getAbsolutePath();
                        String newpath = path.replace('\\', '/');
                        imagepath = newpath.replace("C:/", "/");
                    }else if(nameOS.indexOf("mac") >= 0){
                        String path = file.getAbsolutePath();
                        imagepath = path.replace("~/", "/");
                    }     
                    image = ImageIO.read(new File(imagepath));
                } catch (IOException ioe) {ioe.getCause();}
            }
        
        
        @Override
        public void paintComponent(Graphics g) {
            //comment out the next two lines and un comment the third and the image
            //will be displayed large, otherwise it will resized as long as 
            //frame.setContentPane(desktopPane) is commented out 
            scaledImage = image.getScaledInstance(getWidth(), getHeight(), Image.SCALE_DEFAULT);
            g.drawImage(scaledImage, 0, 0, null);
            //g.drawImage(image, 0, 0, null);
        }
    }
    
    public ResizeImageProblem() {
        //initialize JFrame
        frame = new JFrame();
        //set JFrame frame window properties
        frame.setTitle("Resize Image Problem");
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        //screenSize.width -= 683;
        screenSize.height -= 45;
        frame.setSize(screenSize);
        frame.setLocation(0, 3);
        frame.setResizable(false);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        //initialize menuBar
        JMenuBar menuBar = new JMenuBar();
        frame.setJMenuBar(menuBar);
        //initialize techMenu
        techMenu = new JMenu("Technician Class");
        techMenu.setBorder(BorderFactory.createEmptyBorder(0, 20, 0, 0));
        techMenu.setFont(new Font("Times New Roman", Font.BOLD, 14));
        techMenu.setMnemonic('T');
        menuBar.add(techMenu);
        //initialize tech menu menu items
        openTech = new JMenuItem("Open Technician...");
        openTech.setBorder(BorderFactory.createEmptyBorder(5, 0, 5, 0));
        openTech.setAccelerator(KeyStroke.getKeyStroke("control T"));
        openTech.setFont(new Font("Times New Roman", Font.BOLD, 14));
        //set tool tip delay
        toolTipDelay();
        openTech.setToolTipText("Technician Class Exam Questions.");
        techMenu.add(openTech);
        quitTech = new JMenuItem("Quit Technician...");
        quitTech.setBorder(BorderFactory.createEmptyBorder(5, 0, 5, 0));
        quitTech.setAccelerator(KeyStroke.getKeyStroke("control Q"));
        quitTech.setFont(new Font("Times New Roman", Font.BOLD, 14));
        quitTech.setEnabled(false);
        techMenu.add(quitTech);
        // initialize file
        file = new File("background.jpg");
        filename = "background.jpg";
        //if file does not exist send user a message
        boolean exists = file.exists();
        if(!exists){
            //send the user a message about the desktopPane image
            JOptionPane.showMessageDialog(frame, "Can't find " + filename + "! "
                        + "Painting background light gray...", "Error",
                        JOptionPane.ERROR_MESSAGE);
            //initialize desktopPane
            desktopPane = new JDesktopPane();
            desktopPane.setBackground(Color.LIGHT_GRAY);
            frame.setContentPane(desktopPane);
        }else if(exists){
            //initialize desktopPane
            desktopPane = new JDesktopPane();
            /************************************************************/
            frame.setContentPane(desktopPane); // comment out this line
            /************************************************************/
            //add ImagePanel to the ContentPane
            frame.getContentPane().add(new ImagePanel());
        }
        //call Method menuListener
        menuListeners();
        //set internal frames look and feel
        try{
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
            SwingUtilities.updateComponentTreeUI(frame);
        }catch(Exception e){e.getCause();}
        //set JFrame as visible
        frame.setVisible(true);
    }
    
    /**
     * Tool tip delay method.
     */
    private void toolTipDelay(){
        // Show tool tips immediately
        ToolTipManager.sharedInstance().setInitialDelay(0);
    }
    
    /**
     * Add Listener to MenuBar.(according to netbeans 'this' leaks memory in the
     * constructors in the main class, so I add the listeners via method.
     */
    private void menuListeners() {
        openTech.addActionListener(this);
        quitTech.addActionListener(this);
    }
    
    /**
     * Constructors for techFrame.
     */
    private void openTechFrame() {
        //initialize techFrame
        techFrame = new JInternalFrame("Technician Class", false, true, false, false);               
        // set frame properties
        techFrame.setTitle("Technicain Class Exam Pool");
        techFrame.setSize(550,650);
        // Get the size of the screen
        Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
        // Determine the location of the default application.
        int w = getSize().width;
        int h = getSize().height;
        int x = ((dim.width-w)/2)-280;
        int y = ((dim.height-h)/2)-400;
        techFrame.setLocation(x, y);
        techFrame.setResizable(false);
        techFrame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        techFrame.addInternalFrameListener(this);
        techFrame.setFocusable(true);
        desktopPane.add(techFrame);
        //set internal frame techFrame as selectable
        try {
            techFrame.setSelected(true);
        }catch(java.beans.PropertyVetoException v){v.getCause();}
        techFrame.setVisible(true);
    }
    
    /**
     * ActionEvent Listeners.
     * @param ae 
     */
    @Override
    public void actionPerformed(ActionEvent ae) {
        if(ae.getSource() == openTech) {
            openTechFrame();
        }else if(ae.getSource() == quitTech) {
            techFrame.dispose();
        }
    }
    
    /**
     * InternalFrame Listeners.
     * @param e 
     */
    @Override
    public void internalFrameClosing(InternalFrameEvent e) {}

    @Override
    public void internalFrameClosed(InternalFrameEvent e) {
        //enable disable JMenu menuItems
        if(e.getInternalFrame() == techFrame){
            openTech.setEnabled(true);
            quitTech.setEnabled(false);
        }
    }

    @Override
    public void internalFrameOpened(InternalFrameEvent e){
        //enable disable JMenu menuItems
        if(e.getInternalFrame() == techFrame){
            openTech.setEnabled(false);
            quitTech.setEnabled(true);
        }
    }

    @Override
    public void internalFrameIconified(InternalFrameEvent e){}

    @Override
    public void internalFrameDeiconified(InternalFrameEvent e){}

    @Override
    public void internalFrameActivated(InternalFrameEvent e){}
    
    @Override
    public void internalFrameDeactivated(InternalFrameEvent e){}
    
    /**
     * Run Program
     * @param args 
     */
    public static void main(String[] args){
        javax.swing.SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run(){
                ResizeImageProblem rip = new ResizeImageProblem();
            }
        });
    }
}

[switch]

I solved it with three lines of code. Now I feel stupid. Go figure.

//class required for setting the ContentPane image
    class ImagePanel extends JPanel {
        
        private Image img;
        Dimension screensize = Toolkit.getDefaultToolkit().getScreenSize();
        int w = screensize.width;
        int h = screensize.height;
                        
        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);
        }
        
        @Override
        public void paintComponent(Graphics g) {
            g.drawImage(img, 0, 0, w, h, null);
        }
    }

[switch]

I tried using another image with planets and I was very surprised that the image didn't loose its aspect ratio. The planets remained round not ovals.
switch

[switch]

I forgot to tell those of you that are interested how I called the class ImagePanel. Here's the code:

//initialize desktopPane
desktopPane = new JDesktopPane();
frame.setContentPane(desktopPane);
//add ImagePanel to the ContentPane
ImagePanel panel = new ImagePanel(new ImageIcon(imagepath).getImage());
frame.getContentPane().add(panel);