How to resize the Icon in JTree at my will??

[Michelle Wang]

Hi, all:

I have following code to add the Icon to the nodes of the JTree,
But I hope to resize the Icon such as 1.gif, 2.gif, 3.gif etc at my will, not fixed one, How can I do it??
Thanks
Sunny

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;

/** JTree with missing or custom icons at the tree nodes.
* 1999 Marty Hall, http://www.apl.jhu.edu/~hall/java/
*/

public class CustomIcons extends JFrame {
public static void main(String[] args) {
new CustomIcons();
}

private ImageIcon customOpenIcon = new ImageIcon("1.gif");
private ImageIcon customClosedIcon = new ImageIcon("2.gif");
private ImageIcon customLeafIcon = new ImageIcon("3.gif");

public CustomIcons() {
super("JTree Selections");
// WindowUtilities.setNativeLookAndFeel();
// addWindowListener(new ExitListener());

Container content = getContentPane();
content.setLayout(new FlowLayout());
DefaultMutableTreeNode root =
new DefaultMutableTreeNode("Root");
DefaultMutableTreeNode child;
DefaultMutableTreeNode grandChild;
for(int childIndex=1; childIndex<4; childIndex++) {
child = new DefaultMutableTreeNode("Child " + childIndex);
root.add(child);
for(int grandChildIndex=1; grandChildIndex<4; grandChildIndex++) {
grandChild =
new DefaultMutableTreeNode("Grandchild " + childIndex +
"." + grandChildIndex);
child.add(grandChild);
}
}

JTree tree1 = new JTree(root);
tree1.expandRow(1); // Expand children to illustrate leaf icons
JScrollPane pane1 = new JScrollPane(tree1);
pane1.setBorder(BorderFactory.createTitledBorder("Standard Icons"));
content.add(pane1);

JTree tree2 = new JTree(root);
tree2.expandRow(2); // Expand children to illustrate leaf icons
DefaultTreeCellRenderer renderer2 = new DefaultTreeCellRenderer();
renderer2.resize(100, 100);
renderer2.setOpenIcon(null);
renderer2.setClosedIcon(null);
renderer2.setLeafIcon(null);
tree2.setCellRenderer(renderer2);
JScrollPane pane2 = new JScrollPane(tree2);
pane2.setBorder(BorderFactory.createTitledBorder("No Icons"));
content.add(pane2);

JTree tree3 = new JTree(root);
tree3.expandRow(3); // Expand children to illustrate leaf icons
DefaultTreeCellRenderer renderer3 = new DefaultTreeCellRenderer();

//renderer3.setPreferredSize(new Dimension(100, 100));
renderer3.setOpenIcon(customOpenIcon);
renderer3.setClosedIcon(customClosedIcon);
renderer3.setLeafIcon(customLeafIcon);
tree3.setCellRenderer(renderer3);
JScrollPane pane3 = new JScrollPane(tree3);
pane3.setBorder(BorderFactory.createTitledBorder("Custom Icons"));
content.add(pane3);

pack();
setVisible(true);
}
}

[Craig Wood]

The newer way to load images is with ImageIO.read which returns a BufferedImage. I had
trouble loading the three images used in the app you posted/linked–to with ImageIO so I kept
the older ImageIcon code below. It shows a way to create a scaled image on–the–fly.

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.tree.*;
 
    public class CustomIconsRx extends JFrame {
        public static void main(String[] args) {
            new CustomIconsRx();
    }
 
    private ImageIcon customOpenIcon;  // = new ImageIcon("Circle_1.gif");
    private ImageIcon customClosedIcon;// = new ImageIcon("Circle_2.gif");
    private ImageIcon customLeafIcon;  // = new ImageIcon("Circle_3.gif");
 
    public CustomIconsRx() {
        super("JTree Selections");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        ImageIcon[] icons = getIcons();
        double scale = 1.20;
        createScaledIcons(icons, scale);
        setContents();
        pack();
        setVisible(true);
    }
 
    private ImageIcon[] getIcons() {
        String[] ids = { "Circle_1.gif", "Circle_2.gif", "Circle_3.gif" };
        ImageIcon[] icons = new ImageIcon[ids.length];
        for(int j = 0; j < icons.length; j++)
            icons[j] = new ImageIcon(ids[j]);
        return icons;
    }
 
    private void createScaledIcons(ImageIcon[] icons, double scale) {
        customOpenIcon   = new ImageIcon(scale(icons[0].getImage(), scale));
        customClosedIcon = new ImageIcon(scale(icons[1].getImage(), scale));
        customLeafIcon   = new ImageIcon(scale(icons[2].getImage(), scale));
    }
 
    private BufferedImage scale(Image src, double scale) {
        int w = (int)(scale*src.getWidth(this));
        int h = (int)(scale*src.getHeight(this));
        // Select type that can accommodate the images found here:
        // <a href="http://www.apl.jhu.edu/~hall/java/Swing-Tutorial/" target="_blank" rel="nofollow">http://www.apl.jhu.edu/~hall/java/Swing-Tutorial/</a>
        //        ComplexExamples/JTrees/images/Circle_1.gif
        int type = BufferedImage.TYPE_INT_ARGB_PRE;
        BufferedImage dest = new BufferedImage(w, h, type);
        Graphics2D g2 = dest.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        AffineTransform at = AffineTransform.getScaleInstance(scale, scale);
        g2.drawImage(src, at, this);
        g2.dispose();
        return dest;
    }
 
    private void setContents() {
        Container content = getContentPane();
        content.setLayout(new FlowLayout());
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
        DefaultMutableTreeNode child;
        DefaultMutableTreeNode grandChild;
        for(int childIndex=1; childIndex<4; childIndex++) {
            child = new DefaultMutableTreeNode("Child " + childIndex);
            root.add(child);
            for(int grandChildIndex=1; grandChildIndex<4; grandChildIndex++) {
                grandChild =
                    new DefaultMutableTreeNode("Grandchild " + childIndex +
                        "." + grandChildIndex);
                child.add(grandChild);
            }
        }
 
        JTree tree1 = new JTree(root);
        tree1.expandRow(1); // Expand children to illustrate leaf icons
        JScrollPane pane1 = new JScrollPane(tree1);
        pane1.setBorder(BorderFactory.createTitledBorder("Standard Icons"));
        content.add(pane1);
 
        JTree tree2 = new JTree(root);
        tree2.expandRow(2); // Expand children to illustrate leaf icons
        DefaultTreeCellRenderer renderer2 = new DefaultTreeCellRenderer();
        renderer2.setOpenIcon(null);
        renderer2.setClosedIcon(null);
        renderer2.setLeafIcon(null);
        tree2.setCellRenderer(renderer2);
        JScrollPane pane2 = new JScrollPane(tree2);
        pane2.setBorder(BorderFactory.createTitledBorder("No Icons"));
        content.add(pane2);
 
        JTree tree3 = new JTree(root);
        tree3.expandRow(3); // Expand children to illustrate leaf icons
        DefaultTreeCellRenderer renderer3 = new DefaultTreeCellRenderer();
        renderer3.setOpenIcon(customOpenIcon);
        renderer3.setClosedIcon(customClosedIcon);
        renderer3.setLeafIcon(customLeafIcon);
        tree3.setCellRenderer(renderer3);
        JScrollPane pane3 = new JScrollPane(tree3);
        pane3.setBorder(BorderFactory.createTitledBorder("Custom Icons"));
        content.add(pane3);
    }
}