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1   package com.melloware.jukes.file.image;
2   
3   import java.awt.Dimension;
4   import java.awt.Graphics;
5   import java.awt.Image;
6   import java.beans.PropertyChangeEvent;
7   import java.beans.PropertyChangeListener;
8   import java.io.File;
9   
10  import javax.swing.ImageIcon;
11  import javax.swing.JComponent;
12  import javax.swing.JFileChooser;
13  
14  
15  /**
16   * Helper for image JFileChooser.
17   * <p>
18   * Copyright (c) 2006
19   * Melloware, Inc. <http://www.melloware.com>
20   * @author Emil A. Lefkof III <info@melloware.com>
21   * @version 4.0
22   */
23  public final class ChooserImagePreview
24      extends JComponent
25      implements PropertyChangeListener {
26      
27      File file = null;
28      ImageIcon thumbnail = null;
29  
30      public ChooserImagePreview(JFileChooser fc) {
31          setPreferredSize(new Dimension(100, 50));
32          fc.addPropertyChangeListener(this);
33      }
34  
35      public void loadImage() {
36          if (file == null) {
37              thumbnail = null;
38              return;
39          }
40  
41          // Don't use createImageIcon (which is a wrapper for getResource)
42          // because the image we're trying to load is probably not one
43          // of this program's own resources.
44          ImageIcon tmpIcon = new ImageIcon(file.getPath());
45          if (tmpIcon != null) {
46              if (tmpIcon.getIconWidth() > 90) {
47                  thumbnail = new ImageIcon(tmpIcon.getImage().getScaledInstance(90, -1, Image.SCALE_DEFAULT));
48              } else {    // no need to miniaturize
49                  thumbnail = tmpIcon;
50              }
51          }
52      }
53  
54      public void propertyChange(PropertyChangeEvent e) {
55          boolean update = false;
56          String prop = e.getPropertyName();
57  
58          // If the directory changed, don't show an image.
59          if (JFileChooser.DIRECTORY_CHANGED_PROPERTY.equals(prop)) {
60              file = null;
61              update = true;
62  
63              // If a file became selected, find out which one.
64          } else if (JFileChooser.SELECTED_FILE_CHANGED_PROPERTY.equals(prop)) {
65              file = (File)e.getNewValue();
66              update = true;
67          }
68  
69          // Update the preview accordingly.
70          if (update) {
71              thumbnail = null;
72              if (isShowing()) {
73                  loadImage();
74                  repaint();
75              }
76          }
77      }
78  
79      protected void paintComponent(Graphics g) {
80          if (thumbnail == null) {
81              loadImage();
82          }
83          if (thumbnail != null) {
84              int x = (getWidth() / 2) - (thumbnail.getIconWidth() / 2);
85              int y = (getHeight() / 2) - (thumbnail.getIconHeight() / 2);
86  
87              if (y < 0) {
88                  y = 0;
89              }
90  
91              if (x < 5) {
92                  x = 5;
93              }
94              thumbnail.paintIcon(this, g, x, y);
95          }
96      }
97  }