t$ = pdf.GetText(id, page, idx, len)
idx
and spanning over len number of characters from a page. Note that character indices start
at 0. If you pass -1 in len, pdf.GetText() will automatically extract all
remaining characters after the specified index.
The page to use must be specified in the page argument. It must be a number in
the range of 1 to the total number of pages in the document and the page must have
been previously loaded using pdf.LoadPage() with the text argument set
to True. The PDF document specified by id must have been previously opened using
pdf.OpenDocument().