Why doesn't ABCPDF count a PDF's layers correctly? - layer

Question

I have the below method that was supposed to return the number of layers in a PDF but it doesn't appear to work. When I pass the path to a PDF file containing two layers, the layer count property has a value of 1. I confirmed with two different PDF readers that there are two layers in the PDF. My only thought is ABCPDF is flattening the PDF layers during the read. If so, how can I prevent that so an accurate count of the number of layers in the PDF is returned?
Thank you
public static int GetPDFLayerCount(string pdfFile)
{
int layerCount = 0;
Doc doc = new Doc();
doc.SetInfo(0, "License", _License);
// Attempt to read File
try
{
if (System.IO.File.Exists(pdfFile) == false)
{
throw new ApplicationException("File does not exist.");
}
doc.Read(pdfFile);
layerCount = doc.LayerCount;
doc.Clear();
doc.Dispose();
}
catch (Exception ex)
{
System.ApplicationException appException = new ApplicationException(ex.Message + "\r\n\r\n" + pdfFile,ex);
throw appException;
}
return layerCount;
}

Answer 1

Below is the same method using iTextSharp. I tested with layered PDF files created in ABCPDF and those that were not and it worked in both instances.
public static int GetPDFLayerCount(string pdfFile, bool includeHiddenLayersInCount = true)
{
int layerCount = 0;
string tempOutputFile = "";
try
{
tempOutputFile = System.IO.Path.GetTempFileName();
iTextSharp.text.pdf.PdfReader pdfReader = new iTextSharp.text.pdf.PdfReader(pdfFile);
iTextSharp.text.pdf.PdfStamper pdfStamper = new iTextSharp.text.pdf.PdfStamper(pdfReader, new System.IO.FileStream(tempOutputFile, System.IO.FileMode.Create));
System.Collections.Generic.Dictionary<string, iTextSharp.text.pdf.PdfLayer> layers = pdfStamper.GetPdfLayers();
layerCount = layers.Count;
if (!includeHiddenLayersInCount)
{
foreach (System.Collections.Generic.KeyValuePair<string, iTextSharp.text.pdf.PdfLayer> dictLayer in layers)
{
iTextSharp.text.pdf.PdfLayer layer = (iTextSharp.text.pdf.PdfLayer)dictLayer.Value;
//On = whether a layer is hidden or visible. If false, layer is hidden.
//
//OnPanel = the visibility of the layer in Acrobat's layer panel. If false, the layer cannot be directly manipulated by the user and appears hidden.
//Note that any children layers will also be absent from the panel.
if (layer.Value.On == false || layer.Value.OnPanel == false)
{
layerCount--;
}
}
}
pdfStamper.Close();
pdfReader.Close();
}
catch (Exception ex)
{
System.ApplicationException appException = new ApplicationException(ex.Message + "\r\n\r\n" + pdfFile, ex);
throw appException;
}
finally
{
try
{
if (!String.IsNullOrEmpty(tempOutputFile))
{
System.IO.File.Delete(tempOutputFile);
}
}
catch (Exception ex)
{
}
}
}