/// <summary>
/// Find the attribute in the parsed exif data
/// </summary>
/// <param name="exif">Parsed exif data</param>
/// <returns>New attribute parsed from the exif or null if there is no such tag</returns>
public Attribute Parse(IExifMetadata exif)
{
var directory = exif.GetDirectoryOfType <T>();
if (directory == null || !directory.ContainsTag(Tag))
{
return(null);
}
try
{
switch (Type)
{
case AttributeType.Int:
return(new Attribute(Name, new IntValue(directory.GetInt32(Tag)), AttributeSource.Metadata));
case AttributeType.Double:
return(new Attribute(Name, new RealValue(directory.GetDouble(Tag)), AttributeSource.Metadata));
case AttributeType.String:
return(new Attribute(Name, new StringValue(directory.GetString(Tag)), AttributeSource.Metadata));
case AttributeType.DateTime:
return(new Attribute(Name, new DateTimeValue(directory.GetDateTime(Tag)), AttributeSource.Metadata));
default:
throw new ArgumentOutOfRangeException();
}
}
catch (MetadataException)
{
// the tag exists but its format is invalid => ignore it
return(null);
}
}
/// <summary>
/// Try parsing thumbnail from exif
/// </summary>
/// <param name="exif">Exif metadata</param>
/// <returns>Thumbnail attribute</returns>
public Attribute Parse(IExifMetadata exif)
{
var dir = exif.GetDirectoryOfType <T>();
if (dir == null)
{
return(null);
}
if (!dir.ContainsTag(ExifThumbnailDirectory.TagThumbnailOffset) ||
!dir.ContainsTag(ExifThumbnailDirectory.TagThumbnailLength))
{
return(null);
}
var offset = dir.GetInt32(ExifThumbnailDirectory.TagThumbnailOffset);
var length = dir.GetInt32(ExifThumbnailDirectory.TagThumbnailLength);
if (length <= 0)
{
return(null);
}
var buffer = new byte[length];
// the offset is from the start of the exif data, not the start of the segment data
// we have to add 6 for the segment header "Exif\0\0"
Array.Copy(exif.Segment.Bytes, offset + 6, buffer, 0, length);
return(new Attribute(_attributeName, new ImageValue(buffer), AttributeSource.Metadata));
}
public Attribute Parse(IExifMetadata exif)
{
return(_attr);
}
