static string?GetExposureProgramDescription(IEnumerable <Directory> directories)
{
// obtain a specific directory
var directory = directories.OfType <ExifSubIfdDirectory>().FirstOrDefault();
if (directory == null)
{
return(null);
}
// create a descriptor
var descriptor = new ExifSubIfdDescriptor(directory);
// get tag description
return(descriptor.GetExposureProgramDescription());
}
private static void Main()
{
const string filePath = "../MetadataExtractor.Tests/Data/withIptcExifGps.jpg";
Console.WriteLine($"Processing file: {filePath}");
// There are multiple ways to get a Metadata object for a file
//
// SCENARIO 1: UNKNOWN FILE TYPE
//
// This is the most generic approach. It will transparently determine the file type and invoke the appropriate
// readers. In most cases, this is the most appropriate usage. This will handle JPEG, TIFF, GIF, BMP and RAW
// (CRW/CR2/NEF/RW2/ORF) files and extract whatever metadata is available and understood.
//
try
{
var directories = ImageMetadataReader.ReadMetadata(filePath);
Print(directories, "Using ImageMetadataReader");
}
catch (ImageProcessingException e)
{
PrintError(e);
}
catch (IOException e)
{
PrintError(e);
}
//
// SCENARIO 2: SPECIFIC FILE TYPE
//
// If you know the file to be a JPEG, you may invoke the JpegMetadataReader, rather than the generic reader
// used in approach 1. Similarly, if you knew the file to be a TIFF/RAW image you might use TiffMetadataReader,
// PngMetadataReader for PNG files, BmpMetadataReader for BMP files, or GifMetadataReader for GIF files.
//
// Using the specific reader offers a very, very slight performance improvement.
//
try
{
var directories = JpegMetadataReader.ReadMetadata(filePath);
Print(directories, "Using JpegMetadataReader");
}
catch (JpegProcessingException e)
{
PrintError(e);
}
catch (IOException e)
{
PrintError(e);
}
//
// APPROACH 3: SPECIFIC METADATA TYPE
//
// If you only wish to read a subset of the supported metadata types, you can do this by
// passing the set of readers to use.
//
// This currently only applies to JPEG file processing.
//
try
{
// Handle only Exif and IPTC from JPEG
var readers = new IJpegSegmentMetadataReader[] { new ExifReader(), new IptcReader() };
var directories = JpegMetadataReader.ReadMetadata(filePath, readers);
Print(directories, "Using JpegMetadataReader for Exif and IPTC only");
}
catch (JpegProcessingException e)
{
PrintError(e);
}
catch (IOException e)
{
PrintError(e);
}
// Write all extracted values to stdout
void Print(IEnumerable <Directory> directories, string method)
{
Console.WriteLine();
Console.WriteLine("-------------------------------------------------");
Console.Write(' '); Console.WriteLine(method);
Console.WriteLine("-------------------------------------------------");
Console.WriteLine();
// Extraction gives us potentially many directories
foreach (var directory in directories)
{
// Each directory stores values in tags
foreach (var tag in directory.Tags)
{
Console.WriteLine(tag);
}
// Each directory may also contain error messages
foreach (var error in directory.Errors)
{
Console.Error.WriteLine("ERROR: " + error);
}
}
}
DateTime?GetTakenDateTime(IEnumerable <Directory> directories)
{
// obtain the Exif SubIFD directory
var directory = directories.OfType <ExifSubIfdDirectory>().FirstOrDefault();
if (directory == null)
{
return(null);
}
// query the tag's value
if (directory.TryGetDateTime(ExifDirectoryBase.TagDateTimeOriginal, out var dateTime))
{
return(dateTime);
}
return(null);
}
string GetExposureProgramDescription(IEnumerable <Directory> directories)
{
// obtain a specific directory
var directory = directories.OfType <ExifSubIfdDirectory>().FirstOrDefault();
if (directory == null)
{
return(null);
}
// create a descriptor
var descriptor = new ExifSubIfdDescriptor(directory);
// get tag description
return(descriptor.GetExposureProgramDescription());
}
void PrintError(Exception exception) => Console.Error.WriteLine($"EXCEPTION: {exception}");
}
