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275 lines
8.0 KiB
Python
275 lines
8.0 KiB
Python
# © 2018 James R. Barlow: github.com/jbarlow83
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#
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# This file is part of OCRmyPDF.
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#
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# OCRmyPDF is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# OCRmyPDF is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with OCRmyPDF. If not, see <http://www.gnu.org/licenses/>.
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import logging
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from io import BytesIO
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from os import fspath
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from unittest.mock import Mock
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import img2pdf
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import pytest
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from PIL import Image
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import pikepdf
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from ocrmypdf import leptonica
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from ocrmypdf.exec import ghostscript, tesseract
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from ocrmypdf.pdfinfo import PdfInfo
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# pytest.helpers is dynamic
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# pylint: disable=no-member
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# pylint: disable=w0612
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pytestmark = pytest.mark.skipif(
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leptonica.get_leptonica_version() < 'leptonica-1.72',
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reason="Leptonica is too old, correlation doesn't work",
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)
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check_ocrmypdf = pytest.helpers.check_ocrmypdf
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run_ocrmypdf = pytest.helpers.run_ocrmypdf
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RENDERERS = ['hocr', 'sandwich']
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def check_monochrome_correlation(
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outdir, reference_pdf, reference_pageno, test_pdf, test_pageno
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):
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gslog = logging.getLogger()
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reference_png = outdir / f'{reference_pdf.name}.ref{reference_pageno:04d}.png'
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test_png = outdir / f'{test_pdf.name}.test{test_pageno:04d}.png'
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def rasterize(pdf, pageno, png):
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if png.exists():
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print(png)
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return
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ghostscript.rasterize_pdf(
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pdf,
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png,
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xres=100,
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yres=100,
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raster_device='pngmono',
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log=gslog,
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pageno=pageno,
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rotation=0,
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)
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rasterize(reference_pdf, reference_pageno, reference_png)
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rasterize(test_pdf, test_pageno, test_png)
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pix_ref = leptonica.Pix.open(reference_png)
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pix_test = leptonica.Pix.open(test_png)
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return leptonica.Pix.correlation_binary(pix_ref, pix_test)
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def test_monochrome_correlation(resources, outdir):
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# Verify leptonica: check that an incorrect rotated image has poor
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# correlation with reference
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corr = check_monochrome_correlation(
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outdir,
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reference_pdf=resources / 'cardinal.pdf',
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reference_pageno=1, # north facing page
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test_pdf=resources / 'cardinal.pdf',
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test_pageno=3, # south facing page
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)
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assert corr < 0.10
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corr = check_monochrome_correlation(
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outdir,
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reference_pdf=resources / 'cardinal.pdf',
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reference_pageno=2,
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test_pdf=resources / 'cardinal.pdf',
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test_pageno=2,
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)
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assert corr > 0.90
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@pytest.mark.slow
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@pytest.mark.parametrize('renderer', RENDERERS)
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def test_autorotate(spoof_tesseract_cache, renderer, resources, outdir):
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# cardinal.pdf contains four copies of an image rotated in each cardinal
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# direction - these ones are "burned in" not tagged with /Rotate
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out = check_ocrmypdf(
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resources / 'cardinal.pdf',
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outdir / 'out.pdf',
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'-r',
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'-v',
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'1',
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'--pdf-renderer',
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renderer,
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env=spoof_tesseract_cache,
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)
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for n in range(1, 4 + 1):
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correlation = check_monochrome_correlation(
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outdir,
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reference_pdf=resources / 'cardinal.pdf',
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reference_pageno=1,
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test_pdf=outdir / 'out.pdf',
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test_pageno=n,
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)
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assert correlation > 0.80
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@pytest.mark.parametrize(
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'threshold, correlation_test',
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[
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('1', 'correlation > 0.80'), # Low thresh -> always rotate -> high corr
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('99', 'correlation < 0.10'), # High thres -> never rotate -> low corr
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],
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)
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def test_autorotate_threshold(
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spoof_tesseract_cache, threshold, correlation_test, resources, outdir
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):
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out = check_ocrmypdf(
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resources / 'cardinal.pdf',
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outdir / 'out.pdf',
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'--rotate-pages-threshold',
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threshold,
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'-r',
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'-v',
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'1',
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env=spoof_tesseract_cache,
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)
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correlation = check_monochrome_correlation(
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outdir,
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reference_pdf=resources / 'cardinal.pdf',
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reference_pageno=1,
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test_pdf=outdir / 'out.pdf',
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test_pageno=3,
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)
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assert eval(correlation_test) # pylint: disable=w0123
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def test_rotated_skew_timeout(resources, outpdf):
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"""This document contains an image that is rotated 90 into place with a
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/Rotate tag and intentionally skewed by altering the transformation matrix.
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This tests for a bug where the combination of preprocessing and a tesseract
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timeout produced a page whose dimensions did not match the original's.
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"""
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input_file = resources / 'rotated_skew.pdf'
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in_pageinfo = PdfInfo(input_file)[0]
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assert (
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in_pageinfo.height_pixels < in_pageinfo.width_pixels
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), "Expected the input page to be landscape"
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assert in_pageinfo.rotation == 90, "Expected a rotated page"
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out = check_ocrmypdf(
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input_file,
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outpdf,
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'--pdf-renderer',
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'hocr',
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'--deskew',
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'--tesseract-timeout',
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'0',
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)
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out_pageinfo = PdfInfo(out)[0]
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w, h = out_pageinfo.width_pixels, out_pageinfo.height_pixels
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assert h > w, "Expected the output page to be portrait"
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assert out_pageinfo.rotation == 0, "Expected no page rotation for output"
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assert (
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in_pageinfo.width_pixels == h and in_pageinfo.height_pixels == w
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), "Expected page rotation to be baked in"
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def test_rotate_deskew_timeout(resources, outdir):
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check_ocrmypdf(
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resources / 'rotated_skew.pdf',
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outdir / 'deskewed.pdf',
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'--rotate-pages',
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'--rotate-pages-threshold',
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'0',
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'--deskew',
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'--tesseract-timeout',
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'0',
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'--pdf-renderer',
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'sandwich',
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)
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correlation = check_monochrome_correlation(
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outdir,
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reference_pdf=resources / 'ccitt.pdf',
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reference_pageno=1,
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test_pdf=outdir / 'deskewed.pdf',
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test_pageno=1,
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)
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# Confirm that the page still got deskewed
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assert correlation > 0.50
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@pytest.mark.slow
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@pytest.mark.parametrize('page_angle', (0, 90, 180, 270))
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@pytest.mark.parametrize('image_angle', (0, 90, 180, 270))
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def test_rotate_page_level(image_angle, page_angle, resources, outdir):
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def make_rotate_test(prefix, image_angle, page_angle):
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im = Image.open(fspath(resources / 'typewriter.png'))
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if image_angle != 0:
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ccw_angle = -image_angle % 360
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im = im.transpose(getattr(Image, f'ROTATE_{ccw_angle}'))
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memimg = BytesIO()
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im.save(memimg, format='PNG')
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memimg.seek(0)
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mempdf = BytesIO()
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img2pdf.convert(
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memimg.read(),
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layout_fun=img2pdf.get_fixed_dpi_layout_fun((200, 200)),
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outputstream=mempdf,
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)
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mempdf.seek(0)
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pike = pikepdf.open(mempdf)
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pike.pages[0].Rotate = page_angle
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target = outdir / f'{prefix}_{image_angle}_{page_angle}.pdf'
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pike.save(target)
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return target
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reference = make_rotate_test('ref', 0, 0)
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test = make_rotate_test('test', image_angle, page_angle)
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out = test.with_suffix('.out.pdf')
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p, _, err = run_ocrmypdf(
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test,
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out,
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'-O0',
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'--rotate-pages',
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'--rotate-pages-threshold',
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'0.001',
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universal_newlines=False,
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)
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err = err.decode('utf-8', errors='replace')
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assert p.returncode == 0, err
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assert check_monochrome_correlation(outdir, reference, 1, out, 1) > 0.2
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def test_tesseract_orientation(resources, tmpdir):
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pix = leptonica.Pix.open(resources / 'crom.png')
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pix_rotated = pix.rotate_orth(2) # 180 degrees clockwise
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pix_rotated.write_implied_format(tmpdir / '000001.png')
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log = Mock()
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tesseract.get_orientation( # Test results of this are unreliable
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tmpdir / '000001.png', engine_mode='3', timeout=10, log=log
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)
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