Question: Trying to add Marked Content and reshuffle OCG's about podofo HOT 1 CLOSED

Hello, I'm not sure I can fully answer all your questions but I will try. First I don't know what "built-in support for OCG" could be in PoDoFo: with PoDoFo you can parse the content stream for a page (or an XObject) and knowing enough PDF specification you can identify and separate the content you are looking for. An example of such parsing can be found here.

Secondly, you can definitely edit the [content stream of a] PDF [page] in situ, I am not sure why you had the feeling this is not possible. Manipulate the contents stream of a page is an explicitly supported use case, and with most recent code in master you can do it abstractly for a PdfCanvas (that is either a page or an XObject) like this:

PdfMemDocument doc;
doc.Load(R"(D:\Test\test.pdf)");
auto& page = doc.GetPages().GetPageAt(0);
auto& canvas = static_cast<PdfCanvas&>(page);

PdfObject tempObj;
auto& newContents = tempObj.GetOrCreateStream();
{
    auto outputStream = stream.GetOutputStream();

    // Parse the contents of the page and rewrite it to "outputStream"
    // ...
}
// Finally set the new stream on the canvas. Output stream must
// be closed before this operation
canvas.ResetContentsStream() = std::move(newContents);

// Save the document
doc.Save(R"(D:\Test\test.pdf)");

You can do both parsing of the original contents stream and serializing operators in a streamline operation, with a method like this:

void SerializeTo(OutputStream& stream, const PdfVariantStack& stack, PdfOperator op, string& buffer)
{
    for (auto it = stack.rbegin(); it != stack.rend(); it++)
    {
        it->ToString(buffer);
        stream.Write(buffer);
        stream.Write(" ");
    }

    stream.Write(PoDoFo::GetPdfOperatorName(op));
    stream.Write("\n");
}

It's also possible to do with 0.10.x API but the method to replace the contents stream is not abstract and you'll have to code it specifically for page and XObject.

from podofo.