JButton with ImageIcon Size Problem

[Lou Pellegrini]

Hi,
I have a JButton with an ImageIcon showing just fine.
I need to be able to resize the button and of course its icon, but when the button gets to small the icon disappears.
Is there a way I can dynamically change the size of the icon to fit the JButton? Or am I stuck making several icon files?
Thank You in Advance for Your Help,
Lou

[KR Campbell]

Hi,
If you are using an ImageIcon then it has a getScaledInstance() method. I seem to remember using this for something similar once.
Regards,
Ken

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;
 
public class ButtonSizing
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new ButtonTestPanel());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}
 
class ButtonTestPanel extends JPanel
{
    BufferedImage image;
 
    public ButtonTestPanel()
    {
        loadImage();
        GridBagLayout gridbag = new GridBagLayout();
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(4,0,4,0);
        gbc.weighty = 1.0;
        gbc.gridwidth = gbc.REMAINDER;
        JPanel left = new JPanel(gridbag);
        left.setBorder(BorderFactory.createTitledBorder("scaled icon"));
        left.add(new JButton(getScaledIcon(image, 1.25)), gbc);
        left.add(new JButton(getScaledIcon(image, 0.75)), gbc);
        left.add(new JButton("normal", getScaledIcon(image, 1.0)), gbc);
        left.add(new JButton(getScaledIcon(image, 0.5)), gbc);
        JPanel right = new JPanel(gridbag);
        right.setBorder(BorderFactory.createTitledBorder("scaled image"));
        right.add(new JButton(new ImageIcon(getScaledImage(image, 1.25))), gbc);
        right.add(new JButton(new ImageIcon(getScaledImage(image, 0.75))), gbc);
        right.add(new JButton("normal", new ImageIcon(getScaledImage(image, 1.0))), gbc);
        right.add(new JButton(new ImageIcon(getScaledImage(image, 0.5))), gbc);
        setLayout(gridbag);
        gbc.gridwidth = 1;
        gbc.weightx = 1.0;
        gbc.fill = gbc.BOTH;
        gbc.insets = new Insets(2,2,2,2);
        add(left, gbc);
        add(right, gbc);
    }
 
    private Image getScaledImage(BufferedImage image, double scale)
    {
        int w = (int)(image.getWidth() * scale);
        int h = (int)(image.getHeight() * scale);
        BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = bi.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BILINEAR);
        //                    RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
        g2.drawRenderedImage(image, at);
        g2.dispose();
        return bi;
    }
 
    private ImageIcon getScaledIcon(final Image image, final double scale)
    {
        ImageIcon scaledIcon = new ImageIcon(image)
        {
            public int getIconWidth()
            {
                return (int)(image.getWidth(null) * scale);
            }
 
            public int getIconHeight()
            {
                return (int)(image.getHeight(null) * scale);
            }
 
            public void paintIcon(Component c, Graphics g, int x, int y)
            {
                g.drawImage(image, x, y, getIconWidth(), getIconHeight(), c);
            }
        };
        return scaledIcon;
    }
 
    private void loadImage()
    {
        String fileName = "images/dukeWaveRed.gif";
        try
        {
            URL url = getClass().getResource(fileName);
            image = ImageIO.read(url);
        }
        catch(MalformedURLException mue)
        {
            System.out.println("bad URL: " + mue.getMessage());
        }
        catch(IOException ioe)
        {
            System.out.println("io help: " + ioe.getMessage());
        }
    }
}

[Lou Pellegrini]

Thank you Craig!
That is exactly what I needed!
Lou