Making a buffered image of a JTable row

[Rich West]

Does anyone have any example code for making a buffered image of a row of a JTable?

Many thanks in advance.

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;
 
public class RowImage
{
    public RowImage()
    {
        JTable table = createTable();
        ActionController controller = new ActionController(table);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(controller.getUIPanel(), "North");
        f.getContentPane().add(new JScrollPane(table));
        f.getContentPane().add(controller.getImagePanel(), "South");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
        controller.createImageOfRow(0);
    }
 
    private JTable createTable()
    {
        String[] headers = { "column 1", "column 2", "column 3", "column 4" };
        int rows = 6, cols = 4;
        String[][] data = new String[rows][cols];
        for(int row = 0; row < rows; row++)
            for(int col = 0; col < cols; col++)
                data[row][col] = "item " + (row * cols + col + 1);
        JTable table = new JTable(data, headers);
        table.setRowHeight(35);
        TableCellRenderer tcr = table.getDefaultRenderer(String.class);
        ((DefaultTableCellRenderer)tcr).setHorizontalAlignment(JLabel.CENTER);
        return table;
    }
 
    public static void main(String[] args)
    {
        new RowImage();
    }
}
 
class ActionController
{
    JTable table;
    JLabel label;
    BufferedImage bi;
 
    public ActionController(JTable table)
    {
        this.table = table;
    }
 
    public void createImageOfRow(int rowIndex)
    {
        int x = table.getX();
        int y = table.getRowHeight() * rowIndex;
        int w = table.getWidth();
        int h = table.getRowHeight();
        bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = bi.createGraphics();
        g2.translate(-x, -y);
        table.paint(g2);
        g2.dispose();
        label.setIcon(new ImageIcon(bi));
    }
 
    private void saveImage()
    {
        try
        {
            ImageIO.write(bi, "png", new File("tableRowImage.png"));
        }
        catch(IOException ioe)
        {
            System.err.println("write: " + ioe.getMessage());
        }
    }
 
    public JPanel getUIPanel()
    {
        int rows = table.getRowCount() - 1;
        final SpinnerNumberModel model = new SpinnerNumberModel(0, 0, rows, 1);
        JSpinner spinner = new JSpinner(model);
        JSpinner.NumberEditor editor = new JSpinner.NumberEditor(spinner);
        editor.getTextField().setHorizontalAlignment(JTextField.CENTER);
        Dimension d = editor.getPreferredSize();
        editor.setPreferredSize(new Dimension(25, d.height));
        spinner.setEditor(editor);
        spinner.addChangeListener(new ChangeListener()
        {
            public void stateChanged(ChangeEvent e)
            {
                int rowIndex = model.getNumber().intValue();
                createImageOfRow(rowIndex);
            }
        });
        JButton save = new JButton("save");
        save.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                saveImage();
            }
        });
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(3,2,3,2);
        gbc.weightx = 1.0;
        gbc.anchor = gbc.EAST;
        panel.add(new JLabel("row index"), gbc);
        gbc.anchor = gbc.WEST;
        panel.add(spinner, gbc);
        gbc.anchor = gbc.CENTER;
        panel.add(save, gbc);
        return panel;
    }
 
    public JPanel getImagePanel()
    {
        label = new JLabel();
        label.setHorizontalAlignment(JLabel.CENTER);
        Dimension d = table.getPreferredSize();
        d.height = table.getRowHeight();
        label.setPreferredSize(d);
        JPanel panel = new JPanel(new BorderLayout());
        panel.add(label);
        return panel;
    }
}