OCRmyPDF/tests/test_pdfinfo.py

# © 2015 James R. Barlow: github.com/jbarlow83
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.


import pickle
from math import isclose

import img2pdf
import pikepdf
import pytest
from PIL import Image
from reportlab.pdfgen.canvas import Canvas

from ocrmypdf import pdfinfo
from ocrmypdf.pdfinfo import Colorspace, Encoding

# pylint: disable=protected-access


def test_single_page_text(outdir):
    filename = outdir / 'text.pdf'
    pdf = Canvas(str(filename), pagesize=(8 * 72, 6 * 72))
    text = pdf.beginText()
    text.setFont('Helvetica', 12)
    text.setTextOrigin(1 * 72, 3 * 72)
    text.textLine(
        "Methink'st thou art a general offence and every" " man should beat thee."
    )
    pdf.drawText(text)
    pdf.showPage()
    pdf.save()

    info = pdfinfo.PdfInfo(filename)

    assert len(info) == 1
    page = info[0]

    assert page.has_text
    assert len(page.images) == 0


def test_single_page_image(outdir):
    filename = outdir / 'image-mono.pdf'

    im_tmp = outdir / 'tmp.png'
    im = Image.new('1', (8, 8), 0)
    for n in range(8):
        im.putpixel((n, n), 1)
    im.save(str(im_tmp), format='PNG')

    imgsize = ((img2pdf.ImgSize.dpi, 8), (img2pdf.ImgSize.dpi, 8))
    layout_fun = img2pdf.get_layout_fun(None, imgsize, None, None, None)

    im_bytes = im_tmp.read_bytes()
    pdf_bytes = img2pdf.convert(
        im_bytes, producer="img2pdf", with_pdfrw=False, layout_fun=layout_fun
    )
    filename.write_bytes(pdf_bytes)

    info = pdfinfo.PdfInfo(filename)

    assert len(info) == 1
    page = info[0]

    assert not page.has_text
    assert len(page.images) == 1

    pdfimage = page.images[0]
    assert pdfimage.width == 8
    assert pdfimage.color == Colorspace.gray

    # DPI in a 1"x1" is the image width
    assert isclose(pdfimage.dpi.x, 8)
    assert isclose(pdfimage.dpi.y, 8)


def test_single_page_inline_image(outdir):
    filename = outdir / 'image-mono-inline.pdf'
    pdf = Canvas(str(filename), pagesize=(8 * 72, 6 * 72))

    im = Image.new('1', (8, 8), 0)
    for n in range(8):
        im.putpixel((n, n), 1)

    # Draw image in a 72x72 pt or 1"x1" area
    pdf.drawInlineImage(im, 0, 0, width=72, height=72)
    pdf.showPage()
    pdf.save()

    info = pdfinfo.PdfInfo(filename)
    print(info)
    pdfimage = info[0].images[0]
    assert isclose(pdfimage.dpi.x, 8)
    assert pdfimage.color == Colorspace.gray
    assert pdfimage.width == 8


def test_jpeg(resources):
    filename = resources / 'c02-22.pdf'

    pdf = pdfinfo.PdfInfo(filename)

    pdfimage = pdf[0].images[0]
    assert pdfimage.enc == Encoding.jpeg
    assert isclose(pdfimage.dpi.x, 150)


def test_form_xobject(resources):
    filename = resources / 'formxobject.pdf'

    pdf = pdfinfo.PdfInfo(filename)
    pdfimage = pdf[0].images[0]
    assert pdfimage.width == 50


def test_no_contents(resources):
    filename = resources / 'no_contents.pdf'

    pdf = pdfinfo.PdfInfo(filename)
    assert len(pdf[0].images) == 0
    assert not pdf[0].has_text


def test_oversized_page(resources):
    pdf = pdfinfo.PdfInfo(resources / 'poster.pdf')
    image = pdf[0].images[0]
    assert image.width * image.dpi.x > 200, "this is supposed to be oversized"


def test_pickle(resources):
    # For multiprocessing we must be able to pickle our information - if
    # this fails then we are probably storing some unpickleabe pikepdf or
    # other external data around
    filename = resources / 'graph_ocred.pdf'
    pdf = pdfinfo.PdfInfo(filename)
    pickle.dumps(pdf)


def test_vector(resources):
    filename = resources / 'vector.pdf'
    pdf = pdfinfo.PdfInfo(filename)
    assert pdf[0].has_vector
    assert not pdf[0].has_text


def test_ocr_detection(resources):
    filename = resources / 'graph_ocred.pdf'
    pdf = pdfinfo.PdfInfo(filename)
    assert not pdf[0].has_vector
    assert pdf[0].has_text


@pytest.mark.parametrize(
    'testfile', ('truetype_font_nomapping.pdf', 'type3_font_nomapping.pdf')
)
def test_corrupt_font_detection(resources, testfile):
    filename = resources / testfile
    pdf = pdfinfo.PdfInfo(filename, detailed_analysis=True)
    assert pdf[0].has_corrupt_text


def test_stack_abuse():
    p = pikepdf.Pdf.new()

    stream = pikepdf.Stream(p, b'q ' * 35)
    with pytest.warns(None) as record:
        pdfinfo.info._interpret_contents(stream)
    assert 'overflowed' in str(record[0].message)

    stream = pikepdf.Stream(p, b'q Q Q Q Q')
    with pytest.warns(None) as record:
        pdfinfo.info._interpret_contents(stream)
    assert 'underflowed' in str(record[0].message)

    stream = pikepdf.Stream(p, b'q ' * 135)
    with pytest.warns(None):
        with pytest.raises(RuntimeError):
            pdfinfo.info._interpret_contents(stream)