GroupDocs.Metadata for .NET 18.8 Release Notes

Major Features

There are the following features and enhancements in this release:

• Refactor the classes representing TIFF tags to bring them in accordance with the tiff specification
• Reduce memory consumption of the JPEG format
• Reduce memory consumption of the TIFF format
• Implement the ability to read EXIF metadata in the PSD format

All Changes

Public API and Backward Incompatible Changes

Refactor the classes representing TIFF tags to bring them in accordance with the TIFF specification

Description

This enhancement affects the classes representing different types of TIFF tags and brings them in accordance with the TIFF specification.

Public API changes

TiffArrayTag class has been added to GroupDocs.Metadata.Formats.Image namespace
TiffAsciiTag.Value property has been marked as obsolete
TagValue property has been added to TiffAsciiTag class
TiffByteTag.Value property has been marked as obsolete
TiffByteTag class is now inherited from TiffArrayTag class
TiffLongTag.Value property has been marked as obsolete
TiffLongTag class is now inherited from TiffArrayTag class
TiffLongTag.TiffLongTag(TiffTagIdEnum, int) constructor has been marked as obsolete
TiffRationalTag.Value property has been marked as obsolete
TiffRationalTag class is now inherited from TiffArrayTag class
TiffRationalTag.TiffRationalTag(TiffTagIdEnum, Rational) constructor has been marked as obsolete
TiffSByteTag.Value property has been marked as obsolete
TiffSByteTag class is now inherited from TiffArrayTag class
TiffSByteTag.TiffSByteTag(TiffTagIdEnum, int) constructor has been marked as obsolete
TiffShortTag.Value property has been marked as obsolete
TiffShortTag class is now inherited from TiffArrayTag class
TiffShortTag.TiffShortTag(TiffTagIdEnum, short) constructor has been marked as obsolete
TiffSLongTag.Value property has been marked as obsolete
TiffSLongTag class is now inherited from TiffArrayTag class
TiffSLongTag.TiffSLongTag(TiffTagIdEnum, int) constructor has been marked as obsolete
TiffSRationalTag.Value property has been marked as obsolete
TiffSRationalTag class is now inherited from TiffArrayTag class
TiffSRationalTag.TiffSRationalTag(TiffTagIdEnum, SRational) constructor has been marked as obsolete
TiffSShortTag.Value property has been marked as obsolete
TiffSShortTag class is now inherited from TiffArrayTag class
TiffSShortTag.TiffSShortTag(TiffTagIdEnum, short) constructor has been marked as obsolete
TiffDoubleTag class has been added to GroupDocs.Metadata.Formats.Image namespace
TiffFloatTag class has been added to GroupDocs.Metadata.Formats.Image namespace
TiffUndefinedTag class has been added to GroupDocs.Metadata.Formats.Image namespace
TiffRationalArrayTag class has been marked as obsolete
ExifProperty class has been marked as obsolete
CompareExifTags(string, string, ComparerSearchType) method has been added to ComparisonFacade class
CompareExifTags(Stream, Stream, ComparerSearchType) method has been added to ComparisonFacade class
ScanExifTags(string, string, SearchCondition) method has been added to SearchFacade class
ScanExifTags(string, string) method has been added to SearchFacade class
ScanExifTags(string, Regex) method has been added to SearchFacade class
ScanExifTags(Stream, string, SearchCondition) method has been added to SearchFacade class
ScanExifTags(Stream, string) method has been added to SearchFacade class
ScanExifTags(Stream, Regex) method has been added to SearchFacade class
ComparisonFacade.CompareExif(string, string, ComparerSearchType) method has been marked as obsolete
ComparisonFacade.CompareExif(Stream, Stream, ComparerSearchType) method has been marked as obsolete
SearchFacade.ScanExif(string, string, SearchCondition) method has been marked as obsolete
SearchFacade.ScanExif(string, string) method has been marked as obsolete
SearchFacade.ScanExif(string, Regex) method has been marked as obsolete
SearchFacade.ScanExif(Stream, string, SearchCondition) method has been marked as obsolete
SearchFacade.ScanExif(Stream, string) method has been marked as obsolete
SearchFacade.ScanExif(Stream, Regex) method has been marked as obsolete

Usecases

Extract values of certain TIFF tags.

using (TiffFormat format = new TiffFormat(@"D:\input.tif"))
{
    TiffTag[] tags = format.GetTags(format.ImageFileDirectories[0]);

    foreach (TiffTag tag in tags)
    {
        if (tag.DefinedTag == TiffTagIdEnum.XResolution || tag.DefinedTag == TiffTagIdEnum.YResolution)
        {
            Console.WriteLine("{0} = {1}", tag.DefinedTag, ((TiffRationalTag)tag).TagValue[0].Value);
        }
    }
}

Since the EXIF metadata standard is based on the TIFF format specification, the classes representing TIFF tags can be used to obtain particular EXIF properties as well.

using (JpegFormat format = new JpegFormat(@"D:\input.jpg"))
{
    ExifInfo exif = format.GetExifInfo();

    if (exif != null)
    {
        foreach (TiffTag tag in exif.Tags)
        {
            if (tag.DefinedTag == TiffTagIdEnum.XResolution || tag.DefinedTag == TiffTagIdEnum.YResolution)
            {
                Console.WriteLine("{0} = {1}", tag.DefinedTag, ((TiffRationalTag) tag).TagValue[0].Value);
            }
        }
    }
}

The ExifProperty class had been duplicating the functionality of TIFF tags and having almost the same purpose, so it was marked as obsolete. Please use the new utility methods returning instances of the TiffTag descendants instead.

TiffTag[] resolutionTags = SearchFacade.ScanExifTags(@"D:\input.jpg", new Regex("^(XResolution|YResolution)$"));

foreach (TiffTag resolutionTag in resolutionTags)
{
    Console.WriteLine("{0} - {1}", resolutionTag.DefinedTag, ((TiffRationalTag)resolutionTag).TagValue[0].Value);
}

TiffTag[] intersection = ComparisonFacade.CompareExifTags(@"D:\input1.jpg", @"D:\input2.jpg", ComparerSearchType.Intersection);

foreach (TiffTag tag in intersection)
{
    Console.WriteLine(tag.DefinedTag);
    Console.WriteLine(tag.TagType);
    Console.WriteLine(tag.GetFormattedValue());
}

Reduce memory consumption of the JPEG format 

Description

This enhancement allows working with jpeg images with less memory consumption.

Public API changes

None.

Usecases

Please note that the JpegFormat class implements the IDisposable interface and it’s necessary to call the Dispose() method when you’re done working with its instance.

using (JpegFormat format = new JpegFormat(@"d:\input.jpg"))
{
    // Working with metadata
}

If you are loading a jpeg file from a stream, it’s up to you to close the stream when the file is not needed anymore.

using (Stream stream = File.Open(@"d:\input.jpg", FileMode.Open, FileAccess.ReadWrite))
{
    using (JpegFormat format = new JpegFormat(stream))
    {
        // Working with metadata
    }
    // The stream is still open here
}

The same rule works if you are saving the output file into a stream.

using (Stream stream = File.Open(@"d:\output.jpg", FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
    using (JpegFormat format = new JpegFormat(@"d:\input.jpg"))
    {
        // Working with metadata

        format.Save(stream);
    }
    // The stream is still open here
}

Reduce memory consumption of the TIFF format 

Description

This enhancement allows working with tiff images with less memory consumption.

Public API changes

None.

Usecases

Please note that the TiffFormat class implements the IDisposable interface and it’s necessary to call the Dispose() method when you’re done working with its instance.

using (TiffFormat format = new TiffFormat(@"d:\input.tiff"))
{
    // Working with metadata
}

If you are loading a tiff file from a stream, it’s up to you to close the stream when the file is not needed anymore.

using (Stream stream = File.Open(@"d:\input.tiff", FileMode.Open, FileAccess.ReadWrite))
{
    using (TiffFormat format = new TiffFormat(stream))
    {
        // Working with metadata
    }
    // The stream is still open here
}

The same rule works if you are saving the output file into a stream.

using (Stream stream = File.Open(@"d:\output.tiff", FileMode.OpenOrCreate, FileAccess.ReadWrite))
{
    using (TiffFormat format = new TiffFormat(@"d:\input.tiff"))
    {
        // Working with metadata

        format.Save(stream);
    }
    // The stream is still open here
}

Implement the ability to read EXIF metadata in the PSD format  

Description

This new feature allows a user to obtain EXIF metadata contained in PSD files.

Public API changes

GetExifInfo method has been added to PsdFormat class

Usecases

Read EXIF metadata of a PSD file

using (PsdFormat format = new PsdFormat(@"D:\input.psd"))
{
    ExifInfo exif = format.GetExifInfo();
    if (exif != null)
    {
        foreach (TiffTag tag in exif.Tags)
        {
            Console.WriteLine(tag.DefinedTag);
            Console.WriteLine(tag.TagType);
            Console.WriteLine(tag.GetFormattedValue());
        }
    }
}