Thumbnail inside JTable

[Emili Calonge]

Can I put a thumbnail inside a JTable?

I create my table from a defaultmodel, then I try this:

 
String ruta;
for (int i = 0; i < getTabla().getModel().getRowCount(); i++){
 ruta = (String) getTabla().getModel().getValueAt(i,3);
 ImageIcon icono = new ImageIcon(ruta);
 Image img = icono.getImage();
 Image newimg = img.getScaledInstance(20, 30, Image.SCALE_SMOOTH);
 icono = new ImageIcon(newimg);
 JLabel preview = new JLabel(icono);
 getTabla().getModel().setValueAt(preview,i,4);
}
 

And I get inside the cell the memory reference:
javax.swing.JLabel[,0,0,0x0,invalid,alignmentX=0.0,alignmentY=0.0,border=,flags=8388608,maximumSize=,minimumSize=,preferredSize=,defaultIcon=javax.swing.ImageIcon@59a34,disabledIcon=,horizontalAlignment=CENTER,horizontalTextPosition=TRAILING,iconTextGap=4,labelFor=,text=,verticalAlignment=CENTER,verticalTextPosition=CENTER]

Does anybody know how to put an image inside a JTable??

[Brian Cole]

try getTabla().getModel().setValueAt(icono, i, 4)

[Emili Calonge]

I forgot to say that I had already done that, but thanks anyway, that doesn't works either, the same thing happens. I think I have to implement a ColumnRenderer, I'll search the forums for some advice. Anyone can tell me where to find it?

[Ken Blair]

You'll have to roll your own renderer, or find a third party renderer that does this. I believe this specific implementation is actually covered in the tutorial at the Sun website.

http://java.sun.com/docs/books/tutorial/uiswing/components/table.html

[Brian Cole]

Actually, JTable does have default renderers
for Icons, but it won't use them unless you
return Icon.class or ImageIcon.class in your
table model's getColumnClass() method.

I should have mentioned that in my previous
posting, sorry. It's the same deal with other
column types such as Boolean, Date, and the
Number classes.

Since you say you're using DefaultTableModel,
you'll have to do something like create an
anonymous inner class to override that method.

[Emili Calonge]

I've decided not to add thumbnails on my JTable, because creating saceld images requires so much time, and as I don't really need thumbnails I prefer keeping the system fast. Thanks anyway if I have some free time I'll try to add thumbnails to the tables, but first I've got other things to do. Thanks anyway.

[Craig Wood]

BufferedImage offers software acceleration.

import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.table.*;
 
public class TableTest
{
    ImageIcon[] icons;
 
    public TableTest(BufferedImage[] source)
    {
        icons = getScaledIcons(source);
    }
 
    private JTable getTable()
    {
        int rows = 4;
        int cols = 4;
        String[] colNames = { "column 1", "column 2", "Image", "column 4" };
        Object[][] data = new Object[rows][cols];
        for(int row = 0; row < rows; row++)
            for(int col = 0; col < cols; col++)
            {
                if(col == 2)
                    data[row][col] = icons[row];
                else
                    data[row][col] = "item " + (row*cols + col + 1);
            }
        DefaultTableModel model = new DefaultTableModel(data, colNames);
        JTable table = new JTable(model)
        {
            public boolean isCellEditable(int row, int col) { return col != 2; }
        };
        table.setRowHeight(30);
        TableColumn col = table.getColumnModel().getColumn(2);
        col.setCellRenderer(new CustomRenderer());
        return table;
    }
 
    private ImageIcon[] getScaledIcons(BufferedImage[] in)
    {
        int w = 20;
        int h = 30;
        ImageIcon[] icons = new ImageIcon[in.length];
        for(int j = 0; j < in.length; j++)
        {
            int type = in[j].getType();
                       //BufferedImage.TYPE_INT_RGB);
            BufferedImage bi = new BufferedImage(w, h, type);
            Graphics2D g2 = bi.createGraphics();
            g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                                RenderingHints.VALUE_INTERPOLATION_BICUBIC);
            g2.setPaint(UIManager.getColor("Table.background"));
            g2.fillRect(0,0,w,h);
            double xScale = (double)w / in[j].getWidth();
            double yScale = (double)h / in[j].getHeight();
            double scale = Math.min(xScale, yScale);    // scale to fit
            double x = (w - scale*in[j].getWidth())/2;
            double y = (h - scale*in[j].getHeight())/2;
            AffineTransform at = AffineTransform.getTranslateInstance(x,y);
            at.scale(scale, scale);
            g2.drawRenderedImage(in[j], at);
            g2.dispose();
            icons[j] = new ImageIcon(bi);
        }
        return icons;
    }
 
    public static void main(String[] args) throws IOException
    {
        String prefix = "images/geek";
        String ext = ".gif";
        String[] paths = { "-c---", "-cg--", "-c-h-", "-c--t" };
        BufferedImage[] images = new BufferedImage[paths.length];
        for(int j = 0; j < images.length; j++)
        {
            String path = prefix + paths[j] + ext;
            images[j] = ImageIO.read(TableTest.class.getResource(path));
        }
        TableTest test = new TableTest(images);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new JScrollPane(test.getTable()));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}
 
class CustomRenderer extends DefaultTableCellRenderer
{
    public Component getTableCellRendererComponent(JTable table,
                                                   Object value,
                                                   boolean isSelected,
                                                   boolean hasFocus,
                                                   int row, int column)
    {
        JLabel label = (JLabel)super.getTableCellRendererComponent(table,
                                   value, isSelected, hasFocus, row, column);
        ImageIcon icon = (ImageIcon)value;
        label.setIcon(icon);
        label.setText("");
        return label;
    }
}