disclaimer: I am the author of borb, the library used in this answer
borb has several classes that process PDF documents. These all implement EventListener. The idea is that they listen to the processing of pdf syntax, and process events (e.g.: an image has been rendered, a string was rendered, a new page has started, etc).
One of these implementations is SimpleParagraphExtraction. It attempts to use geometric information to determine which text should be separated from other text, and when something makes up a line of text, and when several lines make up a paragraph.
This is how you'd use it:
# read document
l: SimpleParagraphExtraction = SimpleParagraphExtraction(maximum_multiplied_leading=Decimal(1.7))
doc: typing.Optional[Document] = None
with open("input.pdf", "rb") as pdf_file_handle:
doc = PDF.loads(pdf_file_handle, [l])
Once you've processed the PDF, you can now do something with the paragraphs you've detected.
for p in l.get_paragraphs_for_page(0):
doc.get_page(0).add_annotation(
SquareAnnotation(p.get_bounding_box(), stroke_color=HexColor("f1cd2e"))
)
The above code adds a colored rectangle around each paragraph.
You can easily modify this code to determine how many paragraphs appear side-by-side. Which should help you determine whether something is single- or multi-column layout.
edit: This is a quick write-up I did:
from pathlib import Path
import typing
from borb.pdf.pdf import PDF
from borb.toolkit.text.simple_paragraph_extraction import SimpleParagraphExtraction
from borb.pdf.canvas.layout.annotation.square_annotation import SquareAnnotation
from borb.pdf import HexColor
from borb.pdf import Paragraph
from decimal import Decimal
import requests
open("example_001.pdf", "wb").write(requests.get("https://github.com/Da-vid21/Outputs/raw/main/BarCvDescLJ11.pdf").content)
open("example_002.pdf", "wb").write(requests.get("https://github.com/Da-vid21/Outputs/raw/main/Bill-Brown-Reprint.pdf").content)
# open PDF
l: SimpleParagraphExtraction = SimpleParagraphExtraction(maximum_multiplied_leading=1.6)
with open("example_002.pdf", "rb") as fh:
doc = PDF.loads(fh, [l])
# build histogram (number of paragraphs per y-coordinate)
ps: typing.List[Paragraph] = l.get_paragraphs_for_page(0)
h: typing.Dict[int, int] = {}
for p in ps:
y0: int = int(p.get_bounding_box().get_y())
y1: int = int(y0 + p.get_bounding_box().get_height())
for y in range(y0, y1):
h[y] = h.get(y, 0) + 1
# display average
avg_paras_per_y: float = sum([x for x in h.values()]) / len(h)
print(avg_paras_per_y)
This outputs:
1.5903010033444815
On average, your two-column document has 1.6 paragraphs per y-coordinate. That would seem to indicate it's a two-column layout.
