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.MetadataException;
   9 import com.drew.metadata.exif.ExifDirectory;
  10 import com.drew.metadata.exif.ExifReader;
  11 import com.drew.metadata.exif.GpsDirectory;
  12
  13 /**
  14  * Class to act as a gateway into the external exif library functions.
  15  * This should be the only class with dependence on the lib-metadata-extractor-java
  16  * classes (which are NOT delivered with GpsPrune).
  17  * This class will not compile without this extra dependency (but is not required if
  18  * the ExifGateway uses the InternalExifLibrary instead).
  19  * Should not be included if the internal library will be used (from jpeg.drew package).
  20  */
  21 public class ExternalExifLibrary implements ExifLibrary
  22 {
  23         /**
  24          * Use the _external_ exif library to get the data from the given file
  25          * @param inFile file to access
  26          * @return Jpeg data if available, otherwise null
  27          */
  28         public JpegData getJpegData(File inFile)
  29         {
  30                 JpegData data = new JpegData();
  31                 // Read exif data from picture
  32                 try
  33                 {
  34                         Metadata metadata = new Metadata();
  35                         new ExifReader(inFile).extract(metadata);
  36                         if (metadata.containsDirectory(GpsDirectory.class))
  37                         {
  38                                 Directory gpsdir = metadata.getDirectory(GpsDirectory.class);
  39                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_LATITUDE)
  40                                         && gpsdir.containsTag(GpsDirectory.TAG_GPS_LONGITUDE)
  41                                         && gpsdir.containsTag(GpsDirectory.TAG_GPS_LATITUDE_REF)
  42                                         && gpsdir.containsTag(GpsDirectory.TAG_GPS_LONGITUDE_REF))
  43                                 {
  44                                         data.setLatitudeRef(gpsdir.getString(GpsDirectory.TAG_GPS_LATITUDE_REF));
  45                                         Rational[] latRats = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_LATITUDE);
  46                                         double seconds = ExifGateway.convertToPositiveValue(latRats[2].getNumerator(), latRats[2].getDenominator());
  47                                         data.setLatitude(new double[] {latRats[0].doubleValue(),
  48                                                 latRats[1].doubleValue(), seconds});
  49                                         data.setLongitudeRef(gpsdir.getString(GpsDirectory.TAG_GPS_LONGITUDE_REF));
  50                                         Rational[] lonRats = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_LONGITUDE);
  51                                         seconds = ExifGateway.convertToPositiveValue(lonRats[2].getNumerator(), lonRats[2].getDenominator());
  52                                         data.setLongitude(new double[] {lonRats[0].doubleValue(),
  53                                                 lonRats[1].doubleValue(), seconds});
  54                                 }
  55
  56                                 // Altitude (if present)
  57                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_ALTITUDE) && gpsdir.containsTag(GpsDirectory.TAG_GPS_ALTITUDE_REF))
  58                                 {
  59                                         data.setAltitude(gpsdir.getRational(GpsDirectory.TAG_GPS_ALTITUDE).intValue());
  60                                         byte altRef = (byte) gpsdir.getInt(GpsDirectory.TAG_GPS_ALTITUDE_REF);
  61                                         data.setAltitudeRef(altRef);
  62                                 }
  63
  64                                 try
  65                                 {
  66                                         // Timestamp and datestamp (if present)
  67                                         final int TAG_GPS_DATESTAMP = 0x001d;
  68                                         if (gpsdir.containsTag(GpsDirectory.TAG_GPS_TIME_STAMP) && gpsdir.containsTag(TAG_GPS_DATESTAMP))
  69                                         {
  70                                                 Rational[] times = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_TIME_STAMP);
  71                                                 data.setGpsTimestamp(new int[] {times[0].intValue(), times[1].intValue(),
  72                                                         times[2].intValue()});
  73                                                 Rational[] dates = gpsdir.getRationalArray(TAG_GPS_DATESTAMP);
  74                                                 if (dates != null) {
  75                                                         data.setGpsDatestamp(new int[] {dates[0].intValue(), dates[1].intValue(), dates[2].intValue()});
  76                                                 }
  77                                         }
  78                                 }
  79                                 catch (MetadataException me) {} // ignore, use other tags instead
  80
  81                                 // Image bearing (if present)
  82                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_IMG_DIRECTION) && gpsdir.containsTag(GpsDirectory.TAG_GPS_IMG_DIRECTION_REF))
  83                                 {
  84                                         Rational bearing = gpsdir.getRational(GpsDirectory.TAG_GPS_IMG_DIRECTION);
  85                                         if (bearing != null) {
  86                                                 data.setBearing(bearing.doubleValue());
  87                                         }
  88                                 }
  89                         }
  90
  91                         // Tags from Exif directory
  92                         if (metadata.containsDirectory(ExifDirectory.class))
  93                         {
  94                                 Directory exifdir = metadata.getDirectory(ExifDirectory.class);
  95
  96                                 // Take time and date from exif tags
  97                                 if (exifdir.containsTag(ExifDirectory.TAG_DATETIME_ORIGINAL)) {
  98                                         data.setOriginalTimestamp(exifdir.getString(ExifDirectory.TAG_DATETIME_ORIGINAL));
  99                                 }
 100                                 // Also take "digitized" timestamp
 101                                 if (exifdir.containsTag(ExifDirectory.TAG_DATETIME_DIGITIZED)) {
 102                                         data.setDigitizedTimestamp(exifdir.getString(ExifDirectory.TAG_DATETIME_DIGITIZED));
 103                                 }
 104
 105                                 // Photo rotation code
 106                                 if (exifdir.containsTag(ExifDirectory.TAG_ORIENTATION)) {
 107                                         data.setOrientationCode(exifdir.getInt(ExifDirectory.TAG_ORIENTATION));
 108                                         // NOTE: this presumably takes the _last_ orientation value found, not the first.
 109                                 }
 110
 111                                 // Thumbnail
 112                                 if (exifdir.containsTag(ExifDirectory.TAG_THUMBNAIL_DATA))
 113                                 {
 114                                         // Make a copy of the byte data rather than keeping a reference to extracted array
 115                                         byte[] tdata = exifdir.getByteArray(ExifDirectory.TAG_THUMBNAIL_DATA);
 116                                         byte[] thumb = new byte[tdata.length];
 117                                         System.arraycopy(tdata, 0, thumb, 0, tdata.length);
 118                                         data.setThumbnailImage(thumb);
 119                                 }
 120                         }
 121
 122                 }
 123                 catch (Exception e) {
 124                         // Exception reading metadata, just ignore it
 125                         //System.err.println("Error: " + e.getClass().getName() + " - " + e.getMessage());
 126                 }
 127                 return data;
 128         }
 129
 130
 131         /**
 132          * Check whether the exifreader class can be correctly resolved
 133          * @return true if it looks ok
 134          */
 135         public boolean looksOK()
 136         {
 137                 try {
 138                         String test = ExifReader.class.getName();
 139                         if (test != null) return true;
 140                 }
 141                 catch (LinkageError le) {}
 142                 return false;
 143         }
 144 }