git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/gui/help/tours/Slide.java

   1 package net.sf.openrocket.gui.help.tours;
   2
   3 import java.awt.image.BufferedImage;
   4 import java.io.IOException;
   5 import java.lang.ref.SoftReference;
   6 import java.net.URL;
   7
   8 import javax.imageio.ImageIO;
   9
  10 import net.sf.openrocket.util.BugException;
  11
  12 /**
  13  * An individual slide in a guided tour.  It contains a image (or reference to an
  14  * image file) plus a text description (in HTML).
  15  *
  16  * @author Sampo Niskanen <sampo.niskanen@iki.fi>
  17  */
  18 public class Slide {
  19         private static final String NO_IMAGE = "none";
  20
  21         private final String imageFile;
  22         private SoftReference<BufferedImage> imageReference = null;
  23
  24         private final String text;
  25
  26
  27
  28         public Slide(String imageFile, String text) {
  29                 this.imageFile = imageFile;
  30                 this.text = text;
  31         }
  32
  33
  34
  35         public BufferedImage getImage() {
  36
  37                 if (imageFile.equals(NO_IMAGE)) {
  38                         return new BufferedImage(0, 0, BufferedImage.TYPE_INT_ARGB);
  39                 }
  40
  41                 // Check the cache
  42                 if (imageReference != null) {
  43                         BufferedImage image = imageReference.get();
  44                         if (image != null) {
  45                                 return image;
  46                         }
  47                 }
  48
  49                 // Otherwise load and cache
  50                 BufferedImage image = loadImage();
  51                 imageReference = new SoftReference<BufferedImage>(image);
  52
  53                 return image;
  54         }
  55
  56         public String getText() {
  57                 return text;
  58         }
  59
  60
  61
  62         private BufferedImage loadImage() {
  63                 BufferedImage img;
  64
  65                 try {
  66                         URL url = ClassLoader.getSystemResource(imageFile);
  67                         if (url != null) {
  68                                 img = ImageIO.read(url);
  69                         } else {
  70                                 throw new BugException("Could not find image " + imageFile);
  71                         }
  72                 } catch (IOException e) {
  73                         throw new BugException("Error reading image " + imageFile, e);
  74                 }
  75
  76                 return img;
  77         }
  78 }