113 lines
3.8 KiB
Python
113 lines
3.8 KiB
Python
# © 2020 James R. Barlow: github.com/jbarlow83
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#
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# Permission is hereby granted, free of charge, to any person obtaining a
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# copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be included
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# in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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"""Tesseract no-op plugin
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To quickly run tests where getting OCR output is not necessary.
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In 'hocr' mode, create a .hocr file that specifies no text found.
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In 'pdf' mode, convert the image to PDF using another program.
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In orientation check mode, report the orientation is upright.
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"""
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from __future__ import annotations
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import pikepdf
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from PIL import Image
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from ocrmypdf import OcrEngine, OrientationConfidence, hookimpl
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HOCR_TEMPLATE = '''<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<title></title>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name='ocr-system' content='tesseract 4.0.0' />
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<meta name='ocr-capabilities' content='ocr_page ocr_carea ocr_par ocr_line ocrx_word'/>
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</head>
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<body>
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<div class='ocr_page' id='page_1' title='image "x.tif"; bbox 0 0 {0} {1}; ppageno 0'>
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<div class='ocr_carea' id='block_1_1' title="bbox 0 1 {0} {1}">
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<p class='ocr_par' dir='ltr' id='par_1' title="bbox 0 1 {0} {1}">
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<span class='ocr_line' id='line_1' title="bbox 0 1 {0} {1}"><span class='ocrx_word' id='word_1' title="bbox 0 1 {0} {1}"> </span>
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</span>
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</p>
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</div>
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</div>
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</body>
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</html>'''
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class NoopOcrEngine(OcrEngine):
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@staticmethod
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def version():
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return '4.0.0'
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@staticmethod
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def creator_tag(options):
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tag = '-PDF' if options.pdf_renderer == 'sandwich' else ''
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return f"NO-OP {tag} {NoopOcrEngine.version()}"
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def __str__(self):
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return f"NO-OP {NoopOcrEngine.version()}"
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@staticmethod
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def languages(options):
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return {'eng'}
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@staticmethod
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def get_orientation(input_file, options):
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return OrientationConfidence(angle=0, confidence=0.0)
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@staticmethod
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def get_deskew(input_file, options):
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return 0.0
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@staticmethod
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def generate_hocr(input_file, output_hocr, output_text, options):
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with Image.open(input_file) as im, open(
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output_hocr, 'w', encoding='utf-8'
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) as f:
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w, h = im.size
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f.write(HOCR_TEMPLATE.format(str(w), str(h)))
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with open(output_text, 'w') as f:
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f.write('')
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@staticmethod
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def generate_pdf(input_file, output_pdf, output_text, options):
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with Image.open(input_file) as im:
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dpi = im.info['dpi']
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pagesize = im.size[0] / dpi[0], im.size[1] / dpi[1]
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ptsize = pagesize[0] * 72, pagesize[1] * 72
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pdf = pikepdf.new()
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pdf.add_blank_page(page_size=ptsize)
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pdf.save(output_pdf, static_id=True)
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output_text.write_text('')
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@hookimpl
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def get_ocr_engine():
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return NoopOcrEngine()
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