Pull Metadata from an Image - Console C#

This tutorial shows how to access metadata from an image and display it to the console in a C# Windows Console application using the LEADTOOLS SDK.

Required Knowledge

Get familiar with the basic steps of creating a project by reviewing the Add References and Set a License tutorial, before working on the Pull Metadata from an Image - Console C# tutorial.

Create the Project and Add the LEADTOOLS References

Start with a copy of the project created in the Add References and Set a License tutorial. If you do not have that project, follow the steps in that tutorial to create it.

The references needed depend upon the purpose of the project. References can be added by one or the other of the following two methods (but not both). For this project, the following references are needed:

If using NuGet references, this tutorial requires the following NuGet package:

• Leadtools.Pdf

If local DLL references are used, the following DLLs are needed. The DLLs are located at <INSTALL_DIR>\LEADTOOLS22\Bin\Dotnet4\x64:

• Leadtools.dll
• Leadtools.Codecs.dll
• Leadtools.Codecs.Cmp.dll

For a complete list of which Codec DLLs are required for specific formats, refer to File Format Support.

Set the License File

The License unlocks the features needed for the project. It must be set before any toolkit function is called. For details, including tutorials for different platforms, refer to Setting a Runtime License.

There are two types of runtime licenses:

• Evaluation license, obtained at the time the evaluation toolkit is downloaded. It allows the toolkit to be evaluated.
• Deployment license. If a Deployment license file and developer key are needed, refer to Obtaining a License.

Gather and Display the Metadata

With the project created, the references added, and the license set, coding can begin.

In Solution Explorer, open Program.cs. Add the following statements to the using block at the top of Program.cs:

// Using block at the top 
using System; 
using System.IO; 
using System.Collections.Generic; 
using Leadtools; 
using Leadtools.Codecs; 

Add a new method called GatherMetadata and call it in the Main method after SetLicense() call. Add the code below to gather and display the metadata of an image.

static void GatherMetadata() 
{ 
   string srcFile = @"C:\LEADTOOLS22\Resources\Images\cannon.jpg"; 
 
   using (var rasterCodecs = new RasterCodecs()) 
   using (var fileInfo = rasterCodecs.GetInformation(srcFile, false)) 
   { 
      Console.WriteLine("Format: {0}", fileInfo.Format); 
 
      // Check if metadata is supported for the specified file format 
      bool isMetadataItemsSupported = RasterCodecs.MetadataItemsSupported(fileInfo.Format); 
      Console.WriteLine("isMetadataItemsSupported: {0}", isMetadataItemsSupported); 
 
      if (isMetadataItemsSupported) 
      { 
         // Read metadata items 
         IDictionary<string, string> metadata = null; 
         try 
         { 
            metadata = rasterCodecs.ReadMetadataItems(srcFile, 1); 
         } 
         catch (Exception ex) 
         { 
            Console.WriteLine("Unable to read metadata: {0}", ex.Message); 
         } 
 
         if (metadata != null) 
         { 
            Console.WriteLine("Items count: {0}", metadata.Count); 
            foreach (var item in metadata) 
               // Key ex: RasterCodecs.FileMetadataKeyAuthor 
               Console.WriteLine("{0}: {1}", item.Key, item.Value); 
         } 
      } 
   } 
} 

Run the Project

Run the project by pressing F5, or by selecting Debug -> Start Debugging.

If the steps were followed correctly, the application runs and displays information from the sample image within the console. This tutorial uses the sample image from this file path: <INSTALL_DIR>\LEADTOOLS22\Resources\Images\cannon.jpg

Wrap-up

This tutorial showed how to load an image and read its metadata items. Also, it covered how to use the RasterCodecs class.

See Also

• LEADTOOLS RasterCodecs Documentation
• LEADTOOLS SDK Download