Read and write image files in the formats that the JDK supports. Multi-file images are supported.
/*
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.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;
import javax.swing.Box;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.filechooser.FileNameExtensionFilter;
/**
* This program lets you read and write image files in the formats that the JDK supports. Multi-file
* images are supported.
* @version 1.02 2007-08-16
* @author Cay Horstmann
*/
public class ImageIOTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
JFrame frame = new ImageIOFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
/**
* This frame displays the loaded images. The menu has items for loading and saving files.
*/
class ImageIOFrame extends JFrame
{
public ImageIOFrame()
{
setTitle("ImageIOTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
JMenu fileMenu = new JMenu("File");
JMenuItem openItem = new JMenuItem("Open");
openItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
openFile();
}
});
fileMenu.add(openItem);
JMenu saveMenu = new JMenu("Save");
fileMenu.add(saveMenu);
Iterator<String> iter = writerFormats.iterator();
while (iter.hasNext())
{
final String formatName = iter.next();
JMenuItem formatItem = new JMenuItem(formatName);
saveMenu.add(formatItem);
formatItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
saveFile(formatName);
}
});
}
JMenuItem exitItem = new JMenuItem("Exit");
exitItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
System.exit(0);
}
});
fileMenu.add(exitItem);
JMenuBar menuBar = new JMenuBar();
menuBar.add(fileMenu);
setJMenuBar(menuBar);
}
/**
* Open a file and load the images.
*/
public void openFile()
{
JFileChooser chooser = new JFileChooser();
chooser.setCurrentDirectory(new File("."));
String[] extensions = ImageIO.getReaderFileSuffixes();
chooser.setFileFilter(new FileNameExtensionFilter("Image files", extensions));
int r = chooser.showOpenDialog(this);
if (r != JFileChooser.APPROVE_OPTION) return;
File f = chooser.getSelectedFile();
Box box = Box.createVerticalBox();
try
{
String name = f.getName();
String suffix = name.substring(name.lastIndexOf('.') + 1);
Iterator<ImageReader> iter = ImageIO.getImageReadersBySuffix(suffix);
ImageReader reader = iter.next();
ImageInputStream imageIn = ImageIO.createImageInputStream(f);
reader.setInput(imageIn);
int count = reader.getNumImages(true);
images = new BufferedImage[count];
for (int i = 0; i < count; i++)
{
images[i] = reader.read(i);
box.add(new JLabel(new ImageIcon(images[i])));
}
}
catch (IOException e)
{
JOptionPane.showMessageDialog(this, e);
}
setContentPane(new JScrollPane(box));
validate();
}
/**
* Save the current image in a file
* @param formatName the file format
*/
public void saveFile(final String formatName)
{
if (images == null) return;
Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName(formatName);
ImageWriter writer = iter.next();
JFileChooser chooser = new JFileChooser();
chooser.setCurrentDirectory(new File("."));
String[] extensions = writer.getOriginatingProvider().getFileSuffixes();
chooser.setFileFilter(new FileNameExtensionFilter("Image files", extensions));
int r = chooser.showSaveDialog(this);
if (r != JFileChooser.APPROVE_OPTION) return;
File f = chooser.getSelectedFile();
try
{
ImageOutputStream imageOut = ImageIO.createImageOutputStream(f);
writer.setOutput(imageOut);
writer.write(new IIOImage(images[0], null, null));
for (int i = 1; i < images.length; i++)
{
IIOImage iioImage = new IIOImage(images[i], null, null);
if (writer.canInsertImage(i)) writer.writeInsert(i, iioImage, null);
}
}
catch (IOException e)
{
JOptionPane.showMessageDialog(this, e);
}
}
/**
* Gets a set of "preferred" format names of all image writers. The preferred format name is the
* first format name that a writer specifies.
* @return the format name set
*/
public static Set<String> getWriterFormats()
{
TreeSet<String> writerFormats = new TreeSet<String>();
TreeSet<String> formatNames = new TreeSet<String>(Arrays.asList(ImageIO
.getWriterFormatNames()));
while (formatNames.size() > 0)
{
String name = formatNames.iterator().next();
Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName(name);
ImageWriter writer = iter.next();
String[] names = writer.getOriginatingProvider().getFormatNames();
String format = names[0];
if (format.equals(format.toLowerCase())) format = format.toUpperCase();
writerFormats.add(format);
formatNames.removeAll(Arrays.asList(names));
}
return writerFormats;
}
private BufferedImage[] images;
private static Set<String> writerFormats = getWriterFormats();
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 400;
}
Related examples in the same category
