PreviewPane.java

package gafetes;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.beans.*;
import java.io.*;
 
import javax.imageio.ImageIO;
import javax.swing.*;



public class PreviewPane extends JPanel implements PropertyChangeListener {
		private JLabel label;
		private int maxImgWidth;
		public PreviewPane() {
			setLayout(new BorderLayout(5,5));
			setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
			add(new JLabel("Preview:"), BorderLayout.NORTH);
			label = new JLabel();
			label.setBackground(Color.WHITE);
			label.setOpaque(true);
			label.setPreferredSize(new Dimension(200, 200));
			maxImgWidth = 195;
			label.setBorder(BorderFactory.createEtchedBorder());
			add(label, BorderLayout.CENTER);
		}
 
		public void propertyChange(PropertyChangeEvent evt) {
			Icon icon = null;
			if(JFileChooser.SELECTED_FILE_CHANGED_PROPERTY.equals(evt
					.getPropertyName())) {
				File newFile = (File) evt.getNewValue();
				if(newFile != null) {
					String path = newFile.getAbsolutePath();
					if(path.endsWith(".gif") || path.endsWith(".jpg") || path.endsWith(".png") || path.endsWith(".bmp")
                                        || path.endsWith(".GIF") || path.endsWith(".JPG") || path.endsWith(".PNG") || path.endsWith(".BMP")
                                        ) {
						try {
							BufferedImage img = ImageIO.read(newFile);
							float width = img.getWidth();
							float height = img.getHeight();
							float scale = height / width;
							width = maxImgWidth;
							height = (width * scale); // height should be scaled from new width							
							icon = new ImageIcon(img.getScaledInstance(Math.max(1, (int)width), Math.max(1, (int)height), Image.SCALE_SMOOTH));
						}
						catch(IOException e) {
							// couldn't read image.
						}
					}
				}
					
				label.setIcon(icon);
				this.repaint();
						
			}
		}
		
	}