tim/prune/jpeg/ExternalExifLibrary.java

   1 package tim.prune.jpeg;
   2
   3 import java.io.File;
   4
   5 import com.drew.imaging.ImageMetadataReader;
   6 import com.drew.lang.Rational;
   7 import com.drew.metadata.Directory;
   8 import com.drew.metadata.Metadata;
   9 import com.drew.metadata.exif.ExifSubIFDDirectory;
  10 import com.drew.metadata.exif.ExifIFD0Directory;
  11 import com.drew.metadata.exif.ExifReader;
  12 import com.drew.metadata.exif.ExifThumbnailDirectory;
  13 import com.drew.metadata.exif.GpsDirectory;
  14
  15 /**
  16  * Class to act as a gateway into the external exif library functions.
  17  * This should be the only class with dependence on the lib-metadata-extractor-java
  18  * classes (which are NOT delivered with GpsPrune).
  19  * This class will not compile without this extra dependency (but is not required if
  20  * the ExifGateway uses the InternalExifLibrary instead).
  21  * Should not be included if the internal library will be used (from jpeg.drew package).
  22  */
  23 public class ExternalExifLibrary implements ExifLibrary
  24 {
  25         /**
  26          * Use the _external_ exif library to get the data from the given file
  27          * @param inFile file to access
  28          * @return Jpeg data if available, otherwise null
  29          */
  30         public JpegData getJpegData(File inFile)
  31         {
  32                 JpegData data = new JpegData();
  33                 // Read exif data from picture
  34                 try
  35                 {
  36                         Metadata metadata = ImageMetadataReader.readMetadata(inFile);
  37                         if (metadata.containsDirectory(GpsDirectory.class))
  38                         {
  39                                 Directory gpsdir = metadata.getDirectory(GpsDirectory.class);
  40                                 if (gpsdir.containsTag(GpsDirectory.TAG_LATITUDE)
  41                                         && gpsdir.containsTag(GpsDirectory.TAG_LONGITUDE)
  42                                         && gpsdir.containsTag(GpsDirectory.TAG_LATITUDE_REF)
  43                                         && gpsdir.containsTag(GpsDirectory.TAG_LONGITUDE_REF))
  44                                 {
  45                                         data.setLatitudeRef(gpsdir.getString(GpsDirectory.TAG_LATITUDE_REF));
  46                                         Rational[] latRats = gpsdir.getRationalArray(GpsDirectory.TAG_LATITUDE);
  47                                         double seconds = ExifGateway.convertToPositiveValue(latRats[2].getNumerator(), latRats[2].getDenominator());
  48                                         data.setLatitude(new double[] {latRats[0].doubleValue(),
  49                                                 latRats[1].doubleValue(), seconds});
  50                                         data.setLongitudeRef(gpsdir.getString(GpsDirectory.TAG_LONGITUDE_REF));
  51                                         Rational[] lonRats = gpsdir.getRationalArray(GpsDirectory.TAG_LONGITUDE);
  52                                         seconds = ExifGateway.convertToPositiveValue(lonRats[2].getNumerator(), lonRats[2].getDenominator());
  53                                         data.setLongitude(new double[] {lonRats[0].doubleValue(),
  54                                                 lonRats[1].doubleValue(), seconds});
  55                                 }
  56
  57                                 // Altitude (if present)
  58                                 if (gpsdir.containsTag(GpsDirectory.TAG_ALTITUDE) && gpsdir.containsTag(GpsDirectory.TAG_ALTITUDE_REF))
  59                                 {
  60                                         data.setAltitude(gpsdir.getRational(GpsDirectory.TAG_ALTITUDE).intValue());
  61                                         byte altRef = (byte) gpsdir.getInt(GpsDirectory.TAG_ALTITUDE_REF);
  62                                         data.setAltitudeRef(altRef);
  63                                 }
  64
  65                                 // Timestamp and datestamp (if present)
  66                                 final int TAG_DATESTAMP = 0x001d;
  67                                 if (gpsdir.containsTag(GpsDirectory.TAG_TIME_STAMP) && gpsdir.containsTag(TAG_DATESTAMP))
  68                                 {
  69                                         Rational[] times = gpsdir.getRationalArray(GpsDirectory.TAG_TIME_STAMP);
  70                                         data.setGpsTimestamp(new int[] {times[0].intValue(), times[1].intValue(),
  71                                                 times[2].intValue()});
  72                                         Rational[] dates = gpsdir.getRationalArray(TAG_DATESTAMP);
  73                                         if (dates != null) {
  74                                                 data.setGpsDatestamp(new int[] {dates[0].intValue(), dates[1].intValue(), dates[2].intValue()});
  75                                         }
  76                                 }
  77
  78                                 // Image bearing (if present)
  79                                 if (gpsdir.containsTag(GpsDirectory.TAG_IMG_DIRECTION) && gpsdir.containsTag(GpsDirectory.TAG_IMG_DIRECTION_REF))
  80                                 {
  81                                         Rational bearing = gpsdir.getRational(GpsDirectory.TAG_IMG_DIRECTION);
  82                                         if (bearing != null) {
  83                                                 data.setBearing(bearing.doubleValue());
  84                                         }
  85                                 }
  86                         }
  87
  88                         // Tags from Exif directory
  89                         if (metadata.containsDirectory(ExifSubIFDDirectory.class))
  90                         {
  91                                 Directory exifdir = metadata.getDirectory(ExifSubIFDDirectory.class);
  92
  93                                 // Take time and date from exif tags
  94                                 if (exifdir.containsTag(ExifSubIFDDirectory.TAG_DATETIME_ORIGINAL)) {
  95                                         data.setOriginalTimestamp(exifdir.getString(ExifSubIFDDirectory.TAG_DATETIME_ORIGINAL));
  96                                 }
  97                                 // Also take "digitized" timestamp
  98                                 if (exifdir.containsTag(ExifSubIFDDirectory.TAG_DATETIME_DIGITIZED)) {
  99                                         data.setDigitizedTimestamp(exifdir.getString(ExifSubIFDDirectory.TAG_DATETIME_DIGITIZED));
 100                                 }
 101                         }
 102                         if (metadata.containsDirectory(ExifIFD0Directory.class))
 103                         {
 104                                 Directory exifdir = metadata.getDirectory(ExifIFD0Directory.class);
 105
 106                                 // Photo rotation code
 107                                 if (exifdir.containsTag(ExifIFD0Directory.TAG_ORIENTATION)) {
 108                                         data.setOrientationCode(exifdir.getInt(ExifIFD0Directory.TAG_ORIENTATION));
 109                                         // NOTE: this presumably takes the _last_ orientation value found, not the first.
 110                                 }
 111                         }
 112
 113                         if (metadata.containsDirectory(ExifThumbnailDirectory.class))
 114                         {
 115                                 ExifThumbnailDirectory exifdir = metadata.getDirectory(ExifThumbnailDirectory.class);
 116
 117                                 // TODO: Check this thumbnail stuff
 118                                 if (exifdir.hasThumbnailData())
 119                                 {
 120                                         // Make a copy of the byte data
 121                                         byte[] tdata = exifdir.getThumbnailData();
 122                                         byte[] thumb = new byte[tdata.length];
 123                                         System.arraycopy(tdata, 0, thumb, 0, tdata.length);
 124                                         data.setThumbnailImage(thumb);
 125                                 }
 126                         }
 127
 128                 }
 129                 catch (Exception e) {
 130                         // Exception reading metadata, just ignore it
 131                         //System.err.println("Error: " + e.getClass().getName() + " - " + e.getMessage());
 132                 }
 133                 return data;
 134         }
 135
 136
 137         /**
 138          * Check whether the exifreader class can be correctly resolved
 139          * @return true if it looks ok
 140          */
 141         public boolean looksOK()
 142         {
 143                 try {
 144                         String test = ExifReader.class.getName();
 145                         if (test != null) return true;
 146                 }
 147                 catch (LinkageError le) {}
 148                 return false;
 149         }
 150 }