Class Exif

app/src/main/java/androidxc/camera/core/impl/utils/Exif.java:47–889

Utility class for modifying metadata on JPEG files. Call #save() to persist changes to disc.

/**
 * Utility class for modifying metadata on JPEG files.
 *
 * <p>Call {@link #save()} to persist changes to disc.
 */
public final class Exif {

    /** Timestamp value indicating a timestamp value that is either not set or not valid */
    public static final long INVALID_TIMESTAMP = -1;
    // Forked from ExifInterface.TAG_THUMBNAIL_ORIENTATION. The value is library-internal so we
    // can't depend on it directly.
    public static final String TAG_THUMBNAIL_ORIENTATION = "ThumbnailOrientation";

    private static final String TAG = Exif.class.getSimpleName();

    private static final ThreadLocal<SimpleDateFormat> DATE_FORMAT =
            new ThreadLocal<SimpleDateFormat>() {
                @Override
                public SimpleDateFormat initialValue() {
                    return new SimpleDateFormat("yyyy:MM:dd", Locale.US);
                }
            };
    private static final ThreadLocal<SimpleDateFormat> TIME_FORMAT =
            new ThreadLocal<SimpleDateFormat>() {
                @Override
                public SimpleDateFormat initialValue() {
                    return new SimpleDateFormat("HH:mm:ss", Locale.US);
                }
            };
    private static final ThreadLocal<SimpleDateFormat> DATETIME_FORMAT =
            new ThreadLocal<SimpleDateFormat>() {
                @Override
                public SimpleDateFormat initialValue() {
                    return new SimpleDateFormat("yyyy:MM:dd HH:mm:ss", Locale.US);
                }
            };

    private static final String KILOMETERS_PER_HOUR = "K";
    private static final String MILES_PER_HOUR = "M";
    private static final String KNOTS = "N";

    /** All public tags in {@link ExifInterface}. */
    private static final List<String> ALL_EXIF_TAGS = getAllExifTags();
    // Exif tags that should not be copied to the cropped image.
    private static final List<String> DO_NOT_COPY_EXIF_TAGS = Arrays.asList(
            // Dimension-related tags, which might change after cropping.
            ExifInterface.TAG_IMAGE_WIDTH,
            ExifInterface.TAG_IMAGE_LENGTH,
            ExifInterface.TAG_PIXEL_X_DIMENSION,
            ExifInterface.TAG_PIXEL_Y_DIMENSION,
            // Thumbnail-related tags. Currently we do not create thumbnail for cropped images.
            ExifInterface.TAG_COMPRESSION, // Our primary image is always Jpeg.
            ExifInterface.TAG_JPEG_INTERCHANGE_FORMAT,
            ExifInterface.TAG_JPEG_INTERCHANGE_FORMAT_LENGTH,
            ExifInterface.TAG_THUMBNAIL_IMAGE_LENGTH,
            ExifInterface.TAG_THUMBNAIL_IMAGE_WIDTH,
            TAG_THUMBNAIL_ORIENTATION);

    private final ExifInterface mExifInterface;