ImageTransferTest.java Source code

Introduction

Here is the source code for ImageTransferTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

/**
 * This program demonstrates the transfer of images between a Java application and the system
 * clipboard.
 * @version 1.22 2007-08-16
 * @author Cay Horstmann
 */
public class ImageTransferTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new ImageTransferFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * This frame has an image label and buttons for copying and pasting an image.
 */
class ImageTransferFrame extends JFrame {
    public ImageTransferFrame() {
        setTitle("ImageTransferTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

        label = new JLabel();
        image = new BufferedImage(DEFAULT_WIDTH, DEFAULT_HEIGHT, BufferedImage.TYPE_INT_ARGB);
        Graphics g = image.getGraphics();
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, DEFAULT_WIDTH, DEFAULT_HEIGHT);
        g.setColor(Color.RED);
        g.fillOval(DEFAULT_WIDTH / 4, DEFAULT_WIDTH / 4, DEFAULT_WIDTH / 2, DEFAULT_HEIGHT / 2);

        label.setIcon(new ImageIcon(image));
        add(new JScrollPane(label), BorderLayout.CENTER);
        JPanel panel = new JPanel();

        JButton copyButton = new JButton("Copy");
        panel.add(copyButton);
        copyButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                copy();
            }
        });

        JButton pasteButton = new JButton("Paste");
        panel.add(pasteButton);
        pasteButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                paste();
            }
        });

        add(panel, BorderLayout.SOUTH);
    }

    /**
     * Copies the current image to the system clipboard.
     */
    private void copy() {
        Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
        ImageTransferable selection = new ImageTransferable(image);
        clipboard.setContents(selection, null);
    }

    /**
     * Pastes the image from the system clipboard into the image label.
     */
    private void paste() {
        Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
        DataFlavor flavor = DataFlavor.imageFlavor;
        if (clipboard.isDataFlavorAvailable(flavor)) {
            try {
                image = (Image) clipboard.getData(flavor);
                label.setIcon(new ImageIcon(image));
            } catch (UnsupportedFlavorException exception) {
                JOptionPane.showMessageDialog(this, exception);
            } catch (IOException exception) {
                JOptionPane.showMessageDialog(this, exception);
            }
        }
    }

    private JLabel label;
    private Image image;

    private static final int DEFAULT_WIDTH = 300;
    private static final int DEFAULT_HEIGHT = 300;
}

/**
 * This class is a wrapper for the data transfer of image objects.
 */
class ImageTransferable implements Transferable {
    /**
     * Constructs the selection.
     * @param image an image
     */
    public ImageTransferable(Image image) {
        theImage = image;
    }

    public DataFlavor[] getTransferDataFlavors() {
        return new DataFlavor[] { DataFlavor.imageFlavor };
    }

    public boolean isDataFlavorSupported(DataFlavor flavor) {
        return flavor.equals(DataFlavor.imageFlavor);
    }

    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException {
        if (flavor.equals(DataFlavor.imageFlavor)) {
            return theImage;
        } else {
            throw new UnsupportedFlavorException(flavor);
        }
    }

    private Image theImage;
}