iTextSharp] Making pdf with selected layers(OCGs)

[9tontruck]

Hi,

I am working on parsing pdf layers from a pdf file into separate images.

It was really hard to find an library that does this and now I am digging into iTextSharp which seems like it's handling layers.

    public static void CreatePDF( string fileName, string destinationFolder )
    {
        PdfReader reader = new PdfReader( fileName );
        PdfDictionary ocProps = reader.Catalog.GetAsDict( PdfName.OCPROPERTIES );
        PdfDictionary occd = ocProps.GetAsDict( PdfName.D );
        PdfArray order = occd.GetAsArray( PdfName.ORDER );

        List<PdfObject> layers = new List<PdfObject>();
        for( int i = 0; i < order.Size; i++ ) 
        {
            layers.Add( order[ i ] );
        }

        for( int i = 0; i < layers.Count; i++ )
        {
            order.Remove( 0 );
        }

        for( int i = 0; i < layers.Count; i++ )
        {
            order.Add( layers[ i ] );
            PdfStamper stamper = new PdfStamper( reader, new System.IO.FileStream( destinationFolder + "\\test" + i + ".pdf", System.IO.FileMode.CreateNew ) );

            stamper.Close();
            order.Remove( 0 );
        }

        reader.Close();

    }

This is what I did for saving each layers into separate pdf files. Problem is that it creates one-layer pdf in the first loop but it has whole layers as background so it is not perfect one-layer pdf and it occurs error int he second loop which says I need to load the original pdf again.

Does anyone have any tips for separating layers into pdf or image from a multi-layer pdf?

Please help!