/// <summary>
/// Calculates the perceptual hash of the first content image of the book and writes it to a file
/// The perceptual hash may very well take on the value null. If so, the file will contain the literal string "null" (without the quotes) in it.
/// </summary>
/// <param name="parameters">parameters.PHashOutputInfoPath should contain the file path to which the create/write the PHash</param>
public static void CreatePHashArtifact(CreateArtifactsParameters parameters)
{
if (String.IsNullOrWhiteSpace(parameters.PHashOutputInfoPath))
{
return;
}
// This could take a second or more.
string pHash = _book.ComputePHashOfFirstContentImage();
using (var writer = new StreamWriter(parameters.PHashOutputInfoPath, append: false))
{
// Do note that the pHash may be null and it is expected that some books will legitimately have a null pHash
// so we write this value explicitly so that consumers can explicitly detect this.
writer.WriteLine(pHash ?? "null");
}
}
