Advanced search for Image signatures

GroupDocs.Signature provides ImageSearchOptions class to specify different options to search for Image Signatures

bool ReturnContent property allows to return in the image signature its content;
long MinContentSize property with non zero value limits the minimum size of image to return;
long MaxContentSize property with non zero value limits the maximum size of image to return;
FileType ReturnContentType property allows to specify exact image content type

Here are the steps to search for image signatures within the document with GroupDocs.Signature:

Create new instance of Signature class and pass source document path as a constructor parameter.
Instantiate the ImageSearchOptions object according to your requirements and specify search options
Call Search method of Signature class instance and pass ImageSearchOptions to it.
Analyze if needed list of returned list of ImageSignatures

This example shows how to make advanced search for Image signature in the document and further image signatures analyzes with saving image content

using (Signature signature = new Signature("sampleSignaed.docx"))
{
    // setup search options
    ImageSearchOptions searchOptions = new ImageSearchOptions()
    {
        // enable grabbing image content feature
        ReturnContent = true,
        // set minimum size if needed
        MinContentSize = 0,
        // set maximum size if needed
        MaxContentSize = 0,
        // specify exact image type to be returned
        ReturnContentType = FileType.JPEG,
    };
    // search document
    List<ImageSignature> signatures = signature.Search<ImageSignature>(searchOptions);
    Console.WriteLine($"\nSource document ['{fileName}'] contains following image signature(s).");
    // output signatures
    foreach (ImageSignature imageSignature in signatures)
    {
        Console.Write($"Found Image signature at page {imageSignature.PageNumber} and size {imageSignature.Size}.");
        Console.WriteLine($"Location at {imageSignature.Left}-{imageSignature.Top}. Size is {imageSignature.Width}x{imageSignature.Height}.");
    }
    //Save signature images
    string outputPath = System.IO.Path.Combine(Constants.OutputPath, "SearchForImageAdvanced");
    if (!Directory.Exists(outputPath))
    {
        Directory.CreateDirectory(outputPath);
    }
    int i = 0;
    foreach (ImageSignature imageSignature in signatures)
    {
        Console.Write($"Found Image signature at page {imageSignature.PageNumber} and size {imageSignature.Size}.");
        Console.WriteLine($"Location at {imageSignature.Left}-{imageSignature.Top}. Size is {imageSignature.Width}x{imageSignature.Height}.");
        string outputFilePath = System.IO.Path.Combine(outputPath, $"image{i}{imageSignature.Format.Extension}");
        using (FileStream fs = new FileStream(outputFilePath, FileMode.Create))
        {
            fs.Write(imageSignature.Content, 0, imageSignature.Content.Length);
        }
        i++;
    }
}

More resources

GitHub Examples

You may easily run the code above and see the feature in action in our GitHub examples:

Free Online App

Along with full-featured .NET library we provide simple, but powerful free Apps.

You are welcome to eSign PDF, Word, Excel, PowerPoint documents with free to use online GroupDocs Signature App.

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