/// <summary>
/// Combines a header and a byte array of content
/// </summary>
/// <param name="eh">header</param>
/// <param name="content">content</param>
/// <returns>merged byte array</returns>
private static byte[] MergeHeaderAndContent(EmbeddingHeader header, byte[] content)
{
List <byte> retVal = new List <byte>(header.ToByteArray());
retVal.AddRange(content);
return(retVal.ToArray <byte>());
}
/// <summary>
/// Extracts the content from the image
/// </summary>
/// <param name="img">the image from which to extract</param>
/// <param name="planes">the planes to embed in</param>
/// <param name="bitDepth">the bit depth of the embedding</param>
/// <returns>the embedded content, null if a problem occurs</returns>
public static EmbeddingContent Extract(Bitmap img, EmbeddingPlane planes, int bitDepth)
{
// short circuit
if ((img == null) || (bitDepth < 1) || (bitDepth > 8))
{
return(null);
}
// var declatation
EmbeddingContent retVal = null;
try
{
// get the header to determine what to extract
EmbeddingHeader eh = new EmbeddingHeader(img, planes, bitDepth);
// read the bytes
int totalBytesToExtract = eh.ToString().Length + eh.SizeOfContent;
retVal = new EmbeddingContent(SteganographyMethods.ExtractBytes(img, planes, bitDepth, totalBytesToExtract));
}
catch
{
retVal = null;
}
return(retVal);
}