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                                         double seconds = ExifGateway.convertToPositiveValue(latRats[2].getNumerator(), latRats[2].getDenominator());
  46                                         data.setLatitude(new double[] {latRats[0].doubleValue(),
  47                                                 latRats[1].doubleValue(), seconds});
  48                                         data.setLongitudeRef(gpsdir.getString(GpsDirectory.TAG_GPS_LONGITUDE_REF));
  49                                         Rational[] lonRats = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_LONGITUDE);
  50                                         seconds = ExifGateway.convertToPositiveValue(lonRats[2].getNumerator(), lonRats[2].getDenominator());
  51                                         data.setLongitude(new double[] {lonRats[0].doubleValue(),
  52                                                 lonRats[1].doubleValue(), seconds});
  53                                 }
  54
  55                                 // Altitude (if present)
  56                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_ALTITUDE) && gpsdir.containsTag(GpsDirectory.TAG_GPS_ALTITUDE_REF))
  57                                 {
  58                                         data.setAltitude(gpsdir.getRational(GpsDirectory.TAG_GPS_ALTITUDE).intValue());
  59                                         byte altRef = (byte) gpsdir.getInt(GpsDirectory.TAG_GPS_ALTITUDE_REF);
  60                                         data.setAltitudeRef(altRef);
  61                                 }
  62
  63                                 // Timestamp and datestamp (if present)
  64                                 final int TAG_GPS_DATESTAMP = 0x001d;
  65                                 if (gpsdir.containsTag(GpsDirectory.TAG_GPS_TIME_STAMP) && gpsdir.containsTag(TAG_GPS_DATESTAMP))
  66                                 {
  67                                         Rational[] times = gpsdir.getRationalArray(GpsDirectory.TAG_GPS_TIME_STAMP);
  68                                         data.setGpsTimestamp(new int[] {times[0].intValue(), times[1].intValue(),
  69                                                 times[2].intValue()});
  70                                         Rational[] dates = gpsdir.getRationalArray(TAG_GPS_DATESTAMP);
  71                                         if (dates != null) {
  72                                                 data.setGpsDatestamp(new int[] {dates[0].intValue(), dates[1].intValue(), dates[2].intValue()});
  73                                         }
  74                                 }
  75                         }
  76
  77                         // Tags from Exif directory
  78                         if (metadata.containsDirectory(ExifDirectory.class))
  79                         {
  80                                 Directory exifdir = metadata.getDirectory(ExifDirectory.class);
  81
  82                                 // Take time and date from exif tags
  83                                 if (exifdir.containsTag(ExifDirectory.TAG_DATETIME_ORIGINAL)) {
  84                                         data.setOriginalTimestamp(exifdir.getString(ExifDirectory.TAG_DATETIME_ORIGINAL));
  85                                 }
  86                                 // Also take "digitized" timestamp
  87                                 if (exifdir.containsTag(ExifDirectory.TAG_DATETIME_DIGITIZED)) {
  88                                         data.setDigitizedTimestamp(exifdir.getString(ExifDirectory.TAG_DATETIME_DIGITIZED));
  89                                 }
  90
  91                                 // Photo rotation code
  92                                 if (exifdir.containsTag(ExifDirectory.TAG_ORIENTATION)) {
  93                                         data.setOrientationCode(exifdir.getInt(ExifDirectory.TAG_ORIENTATION));
  94                                         // NOTE: this presumably takes the _last_ orientation value found, not the first.
  95                                 }
  96
  97                                 // Thumbnail
  98                                 if (exifdir.containsTag(ExifDirectory.TAG_THUMBNAIL_DATA))
  99                                 {
 100                                         // Make a copy of the byte data rather than keeping a reference to extracted array
 101                                         byte[] tdata = exifdir.getByteArray(ExifDirectory.TAG_THUMBNAIL_DATA);
 102                                         byte[] thumb = new byte[tdata.length];
 103                                         System.arraycopy(tdata, 0, thumb, 0, tdata.length);
 104                                         data.setThumbnailImage(thumb);
 105                                 }
 106                         }
 107
 108                 }
 109                 catch (Exception e) {
 110                         // Exception reading metadata, just ignore it
 111                 }
 112                 return data;
 113         }
 114
 115
 116         /**
 117          * Check whether the exifreader class can be correctly resolved
 118          * @return true if it looks ok
 119          */
 120         public boolean looksOK()
 121         {
 122                 try {
 123                         String test = ExifReader.class.getName();
 124                         if (test != null) return true;
 125                 }
 126                 catch (LinkageError le) {}
 127                 return false;
 128         }
 129 }