after merge PDFs lose layer settings

Question

Is here some tools to merge PDFs with layers?

Tried to merge PDFs with layers with pdftk, fpdf/fpdi, Gswin32c. In any cases output PDF was as simple PDF without layers.

Thanks.

Edit. I am looking for tool suitable for use it in PHP project (PHP classes or executables such as pdftk)

Answer 1

If you mean Optional Content (section 8.11 of ISO3200-1:2008): AFAIK no free one. There's an unmaintained fork of pdfTeX that has basic support for this, though.

You could try Adobe Acrobat or InDesign.

Answer 2

I think more information about your enviroment is needed, but if you are using .NET I've used PDFsharp, an open source library, to merge multiple pdf documents with good results.