Audiobook Producer
7f0b598441
Root cause: clean-up found paragraph breaks from the layout indent of pdftotext -layout
(columns, relative to the smallest indent in the whole chapter). Chapter 1 happened to
have a clean left margin; later pages are skewed and drift 1-2 columns, drop caps push
the first lines right by varying amounts, and some pages wrap text around a label, so
continuation lines were taken as paragraph starts (a blank line inside a sentence).
Fix (all deterministic, all logged to warnings.log):
- pdftext: read each line's position in points (pdftotext -bbox-layout) and attach it to
the layout line it belongs to (units() now carries 'geom'; merged/partial lines get none).
- cleanup: a paragraph starts when a line sits >= 4.5 pt right of the line before it, or
>= 2.5 pt lower than the page's normal line pitch. A line without a position or starting
in lower case never starts a paragraph. Text wrapped beside a drop cap is not a start.
Without positions the old indent rule is still used.
- cleanup: drop cap + small caps on ONE layout line ('F OR MANY YEARS') is repaired like
the two-line form (chapters 4 and 5).
- pageparts.header_zone: the running header is found even when text follows it without a
blank line, and the right-hand header (chapter title, page number sometimes misread as
't5' or 'a') is recognised from the chapter title.
- cleanup: all-capitals lines below the text are captions (removed); an all-capitals line
above the text is kept as a section heading in title case ('The Deferred Preface');
'Right: MARK TWIN' style captions removed; '5. JOY' labels set inside a sentence removed.
- cleanup: paragraph starting with a lone quote mark + lower-case word joins the paragraph
before it; paragraph-leading ' + capital becomes '"' (not elisions such as 'Tis); a bullet
in place of an opening quote becomes '"'; closing quote with no opening quote, and a '1'
that is probably the letter I, are logged only.
- cleanup: mid-line 'worth- while' joined only when certain, otherwise logged.
- tests: new _pipeline/tests/test_cleanup.py (36 tests, 27 fail on the previous code);
test_pipeline.py helper test_piece renamed make_test_piece so pytest stops collecting it.
Chapter 1 text is byte-identical to the approved pilot text.
Re-run for chapters 1-6: cleanup, figures, script, license. Text, script, warnings and
book.json for chapters 2-6 added.
73 lines
2.6 KiB
Python
73 lines
2.6 KiB
Python
"""Recognize the non-text parts of a page: running header, page number, figure caption."""
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import re
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from difflib import SequenceMatcher
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CAPTION_RE = re.compile(r"^\s*(LEFT|RIGHT|ABOVE|BELOW|OPPOSITE|FACING)\s*:\s*([A-Z][A-Z .,'\-]+?)\s*$")
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_NUM_LEAD = re.compile(r"^\s*(\d{1,3})\s{2,}(\S.*)$")
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_NUM_TRAIL = re.compile(r"^(.*\S)\s{2,}(\d{1,3})\s*$")
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_NUM_ONLY = re.compile(r"^\s*(\d{1,3})\s*$")
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def norm(text):
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return re.sub(r"[^a-z]", "", text.lower())
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def similar(a, b):
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return SequenceMatcher(None, norm(a), norm(b)).ratio()
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def _mostly_upper(text):
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letters = [c for c in text if c.isalpha()]
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return (not letters) or sum(c.isupper() for c in letters) / len(letters) > 0.7
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def header_zone(lines, title, extra_titles=()):
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"""The running header at the top of a unit.
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Returns (first_line, last_line_exclusive, page_number or None) or None.
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The header starts at the first non-empty line and runs over the following lines while they are
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upper case (at most 3 lines in all), whether or not a blank line separates it from the text.
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It is a header if it carries a page number next to uppercase text, or reads as the book title or as
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the chapter title (extra_titles: the right-hand page repeats the chapter title, and its page number
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may be misread by the scan as a letter, so no number is found)."""
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i = 0
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while i < len(lines) and not lines[i].strip():
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i += 1
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if i >= len(lines):
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return None
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j = i + 1
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while j < len(lines) and lines[j].strip() and j - i < 3 and _mostly_upper(lines[j]):
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j += 1
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zone = lines[i:j]
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number, rest = None, []
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for ln in zone:
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m = _NUM_LEAD.match(ln) or None
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if m and number is None:
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number, rest = int(m.group(1)), rest + [m.group(2)]
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continue
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m = _NUM_TRAIL.match(ln)
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if m and number is None:
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number, rest = int(m.group(2)), rest + [m.group(1)]
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continue
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m = _NUM_ONLY.match(ln)
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if m and number is None:
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number = int(m.group(1))
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continue
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rest.append(ln)
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text = " ".join(rest)
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if number is not None and _mostly_upper(text) and len(zone) <= 3:
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return i, j, number
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for t in (title,) + tuple(extra_titles):
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if t and similar(text, t) >= 0.9:
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return i, j, None
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return None
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def footer_number(lines):
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"""A lone page number as the last non-empty line. Returns (line_index, number) or None."""
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k = len(lines) - 1
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while k >= 0 and not lines[k].strip():
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k -= 1
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if k >= 0 and _NUM_ONLY.match(lines[k]):
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return k, int(lines[k])
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return None
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