Accessing the PDF StructTreeRoot

[cole-dda]

Is your feature request related to a problem? Please describe.
i want access pdf's structtreeroot,but i search document api,not idea how get it

Describe the solution you'd like
type,value = doc.xref_object(xref)
value is str

i want:
type,value = doc.xref_object(xref,convert=True)
value is python object,such as,dict list str bool None

[JorjMcKie]

Unfortunately, your description is very vague about what your requirement is, what you are trying to achieve ultimately and specificaclly, what the results should be e.g., what is the meaning of the "convert" parameter?
But as a first cut, here is what you can do already:

You can use Document methods xref_get_key(), xref_get_keys() and pdf_catalog() to find the /StructTreeRoot object and its content. This works like this:

1. Find the xref of the catalog: catxref = doc.pdf_catalog()
2. Access the /StructTreeRoot dictionary : structroot = doc.xref_get_key(catxref, "StructTreeRoot")

The result of the second method always is a tuple of strings - see documentation.
Depending on how your PDF is made, three responses are possible:

1. ("null", "null") - this PDF has no StructTreeRoot.
2. ("xref", "n 0 R") - a StructTreeRoot is present and can be found at xref n. Access it via doc.xref_object(n).
3. ("dict", "<< ... >>") - a StructTreeRoot is present and given as the second item.

Before we can talk about an actual enhancement, a lot of clarification work is necessary obviously.
I suggest to do this under the tab "Discussions", and I will transfer this item to there.