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 io import BytesIO
from math import isclose

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

from ocrmypdf import pdfinfo
from ocrmypdf.exceptions import InputFileError
from ocrmypdf.helpers import Resolution
from ocrmypdf.pdfinfo import Colorspace, Encoding
from ocrmypdf.pdfinfo.layout import PDFPage

# pylint: disable=protected-access


def test_single_page_text(outdir):
    filename = outdir / 'text.pdf'
    pdf = Canvas(str(filename), pagesize=(8 * inch, 6 * inch))
    text = pdf.beginText()
    text.setFont('Helvetica', 12)
    text.setTextOrigin(1 * inch, 3 * inch)
    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


@pytest.fixture(scope='session')
def eight_by_eight():
    im = Image.new('1', (8, 8), 0)
    for n in range(8):
        im.putpixel((n, n), 1)
    return im


def test_single_page_image(eight_by_eight, outpdf):
    im = eight_by_eight
    bio = BytesIO()
    im.save(bio, format='PNG')
    bio.seek(0)

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

    with outpdf.open('wb') as f:
        img2pdf.convert(
            bio,
            producer="img2pdf",
            with_pdfrw=False,
            layout_fun=layout_fun,
            outputstream=f,
        )
    info = pdfinfo.PdfInfo(outpdf)

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

    # Draw image in a 72x72 pt or 1"x1" area
    pdf.drawInlineImage(eight_by_eight, 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)


def test_pages_issue700(monkeypatch, resources):
    def get_no_pages(*args, **kwargs):
        return iter([])

    monkeypatch.setattr(PDFPage, 'get_pages', get_no_pages)

    with pytest.raises(InputFileError, match="pdfminer"):
        pdfinfo.PdfInfo(
            resources / 'cardinal.pdf',
            detailed_analysis=True,
            progbar=False,
            max_workers=1,
        )


def test_image_scale0(resources, outpdf):
    with pikepdf.open(resources / 'cmyk.pdf') as cmyk:
        xobj = cmyk.pages[0].as_form_xobject()

        p = pikepdf.Pdf.new()
        p.add_blank_page(page_size=(72, 72))
        objname = p.pages[0].add_resource(
            p.copy_foreign(xobj), pikepdf.Name.XObject, pikepdf.Name.Im0
        )
        print(objname)
        p.pages[0].Contents = pikepdf.Stream(
            p, b"q 0 0 0 0 0 0 cm %s Do Q" % bytes(objname)
        )
        p.save(outpdf)

    pi = pdfinfo.PdfInfo(outpdf, detailed_analysis=True, progbar=False, max_workers=1)
    assert not pi.pages[0]._images[0].dpi.is_finite
    assert pi.pages[0].dpi == Resolution(0, 0)