How do I detect if a PDF contains Type 3 fonts?

How do I quickly detect if a PDF contains Type 3 fonts?

The following code will check for the presence of any Type 3 fonts in the PDF.

PDFDoc doc = new PDFDoc(filepath);
SDFDoc cos_doc = doc.GetSDFDoc();
int num_objs = cos_doc.XRefSize();
for (int i = 1; i < num_objs; ++i)
	Obj obj = cos_doc.GetObj(i);
	if (obj == null || obj.IsFree() || !obj.IsDict()) continue;
	Obj typeFont = obj.FindObj("Type");
	if (typeFont == null || !typeFont.IsName()) continue;
	if (typeFont.GetName().CompareTo("Font") != 0) continue;
	var font = new pdftron.PDF.Font(obj);
	if (font.GetType() == pdftron.PDF.Font.Type.e_Type3)
		Console.WriteLine("Type 3 font found");


Thanks for this. I tried writing it in Python but getting some errors.

        doc = PDFDoc(filepath)
        cos_doc = doc.GetSDFDoc()
        num_objs = cos_doc.XRefSize()
        for idx in range(num_objs):
            obj = cos_doc.GetObj(idx)
            if obj is None or obj.IsFree() or not obj.IsDict():
            typeFont = obj.FindObj("Type")
            if typeFont is None or not typeFont.IsName() or typeFont.GetName() != "Font":
            font = Font(typeFont)
            if font.GetType() == Font.e_Type3:
                return True
        return False

but getting an error of

     font = Font(typeFont)
   File "../lib/python3.9/site-packages/PDFNetPython3/", line 7929, in __init__
     _PDFNetPython.Font_swiginit(self, _PDFNetPython.new_Font(*args))
 Exception: Get() can't be invoked on Obj of this type.

My gut feel is something missing in the Python bindings. Any suggestions?

Hi Kenneth,

Your error is in the following line:

font = Font(typeFont)

It should instead be:

font = Font(obj)

Matching what was initially written in the forum post.

My bad, must be my eyes then.
Amazing, it works now. Thanks for quick response.