tim/prune/jpeg/ExternalExifLibrary.java

   1 package tim.prune.jpeg;
   2
   3 import java.io.File;
   4
   5 import com.drew.lang.Rational;
   6 import com.drew.metadata.Directory;
   7 import com.drew.metadata.Metadata;
   8 import com.drew.metadata.exif.ExifDirectory;
   9 import com.drew.metadata.exif.ExifReader;
  10 import com.drew.metadata.exif.GpsDirectory;
  11
  12 /**
  13  * Class to act as a gateway into the external exif library functions.
  14  * This should be the only class with dependence on the lib-metadata-extractor-java
  15  * classes (which are NOT delivered with Prune).
  16  * This class will not compile without this extra dependency (but is not required if
  17  * the ExifGateway uses the InternalExifLibrary instead).
  18  * Should not be included if the internal library will be used (from jpeg.drew package).
  19  */
  20 public class ExternalExifLibrary implements ExifLibrary
  21 {
  22         /**
  23          * Use the _external_ exif library to get the data from the given file
  24          * @param inFile file to access
  25          * @return Jpeg data if available, otherwise null
  26          */
  27         public JpegData getJpegData(File inFile)
  28         {
  29                 JpegData data = new JpegData();
  30                 // Read exif data from picture
  31                 try
  32                 {
  33                         Metadata metadata = new Metadata();
  34                         new ExifReader(inFile).extract(metadata);
  35                         if (metadata.containsDirectory(GpsDirectory.class))
  36                         {
  37                                 Directory gpsdir = metadata.getDirectory(GpsDirectory.class);
  38                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_LATITUDE)
  39                                         && gpsdir.containsTag(GpsDirectory.TAG_GPS_LONGITUDE)
  40                                         && gpsdir.containsTag(GpsDirectory.TAG_GPS_LATITUDE_REF)
  41                                         && gpsdir.containsTag(GpsDirectory.TAG_GPS_LONGITUDE_REF))
  42                                 {
  43                                         data.setLatitudeRef(gpsdir.getString(GpsDirectory.TAG_GPS_LATITUDE_REF));
  44                                         Rational[] latRats = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_LATITUDE);
  45                                         data.setLatitude(new double[] {latRats[0].doubleValue(),
  46                                                 latRats[1].doubleValue(), latRats[2].doubleValue()});
  47                                         data.setLongitudeRef(gpsdir.getString(GpsDirectory.TAG_GPS_LONGITUDE_REF));
  48                                         Rational[] lonRats = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_LONGITUDE);
  49                                         data.setLongitude(new double[] {lonRats[0].doubleValue(),
  50                                                 lonRats[1].doubleValue(), lonRats[2].doubleValue()});
  51                                 }
  52
  53                                 // Altitude (if present)
  54                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_ALTITUDE) && gpsdir.containsTag(GpsDirectory.TAG_GPS_ALTITUDE_REF))
  55                                 {
  56                                         data.setAltitude(gpsdir.getRational(GpsDirectory.TAG_GPS_ALTITUDE).intValue());
  57                                         byte altRef = (byte) gpsdir.getInt(GpsDirectory.TAG_GPS_ALTITUDE_REF);
  58                                         data.setAltitudeRef(altRef);
  59                                 }
  60
  61                                 // Timestamp and datestamp (if present)
  62                                 final int TAG_GPS_DATESTAMP = 0x001d;
  63                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_TIME_STAMP) && gpsdir.containsTag(TAG_GPS_DATESTAMP))
  64                                 {
  65                                         Rational[] times = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_TIME_STAMP);
  66                                         data.setGpsTimestamp(new int[] {times[0].intValue(), times[1].intValue(),
  67                                                 times[2].intValue()});
  68                                         Rational[] dates = gpsdir.getRationalArray(TAG_GPS_DATESTAMP);
  69                                         data.setGpsDatestamp(new int[] {dates[0].intValue(), dates[1].intValue(), dates[2].intValue()});
  70                                 }
  71                         }
  72
  73                         // Tags from Exif directory
  74                         if (metadata.containsDirectory(ExifDirectory.class))
  75                         {
  76                                 Directory exifdir = metadata.getDirectory(ExifDirectory.class);
  77
  78                                 // Take time and date from exif tags if haven't got it already from GPS
  79                                 if (data.getGpsDatestamp() == null && exifdir.containsTag(ExifDirectory.TAG_DATETIME_ORIGINAL)) {
  80                                         data.setOriginalTimestamp(exifdir.getString(ExifDirectory.TAG_DATETIME_ORIGINAL));
  81                                 }
  82
  83                                 // Photo rotation code
  84                                 if (exifdir.containsTag(ExifDirectory.TAG_ORIENTATION)) {
  85                                         data.setOrientationCode(exifdir.getInt(ExifDirectory.TAG_ORIENTATION));
  86                                         // NOTE: this presumably takes the _last_ orientation value found, not the first.
  87                                 }
  88
  89                                 // Thumbnail
  90                                 if (exifdir.containsTag(ExifDirectory.TAG_THUMBNAIL_DATA))
  91                                 {
  92                                         // Make a copy of the byte data rather than keeping a reference to extracted array
  93                                         byte[] tdata = exifdir.getByteArray(ExifDirectory.TAG_THUMBNAIL_DATA);
  94                                         byte[] thumb = new byte[tdata.length];
  95                                         System.arraycopy(tdata, 0, thumb, 0, tdata.length);
  96                                         data.setThumbnailImage(thumb);
  97                                 }
  98                         }
  99
 100                 }
 101                 catch (Exception e) {
 102                         // Exception reading metadata, just ignore it
 103                 }
 104                 return data;
 105         }
 106
 107         /**
 108          * Check whether the exifreader class can be correctly resolved
 109          * @return true if it looks ok
 110          */
 111         public boolean looksOK()
 112         {
 113                 try {
 114                         String test = ExifReader.class.getName();
 115                         if (test != null) return true;
 116                 }
 117                 catch (LinkageError le) {}
 118                 return false;
 119         }
 120 }