PDF-Extractor / pipeline /textlayer.py
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"""PyMuPDF text-layer extraction with reading-order reconstruction.
These helpers operate on ``fitz.Page`` objects. ``has_text_layer`` decides
whether the embedded text layer is rich enough to use directly, and
``extract_text_layer`` reconstructs paragraphs in natural reading order from
the page's structured ``"dict"`` output.
"""
def has_text_layer(page, *, min_chars: int = 50) -> bool:
"""Return True if the page's text layer has enough alphanumeric content.
Counts alphanumeric characters in the stripped text layer and compares
against ``min_chars``. Whitespace and punctuation-only layers (common in
scanned PDFs with stray marks) are treated as having no usable text.
"""
try:
text = page.get_text("text") or ""
except Exception:
return False
alnum = sum(1 for ch in text if ch.isalnum())
return alnum >= min_chars
def extract_text_layer(page) -> str:
"""Reconstruct page text in reading order from the structured dict.
Blocks are sorted by their bounding box ``(y0, x0)``. Within each block,
line order is preserved and the spans of a line are concatenated. Lines are
joined by ``"\n"`` and blocks are separated by ``"\n\n"`` to approximate
paragraph structure.
NOTE: the flat ``(y0, x0)`` sort assumes a SINGLE-column layout. On a
multi-column page, blocks at similar vertical positions in different columns
interleave, so the reconstructed text zig-zags between columns (every
character is captured, but the reading order is scrambled). Column-aware
reordering is not implemented yet.
"""
try:
data = page.get_text("dict")
except Exception:
return ""
blocks = data.get("blocks", []) if isinstance(data, dict) else []
text_blocks = []
for block in blocks:
# Only text blocks have "lines"; image blocks (type 1) are skipped.
if block.get("type", 0) != 0:
continue
lines = block.get("lines")
if not lines:
continue
bbox = block.get("bbox", [0.0, 0.0, 0.0, 0.0])
y0 = float(bbox[1]) if len(bbox) > 1 else 0.0
x0 = float(bbox[0]) if len(bbox) > 0 else 0.0
text_blocks.append((y0, x0, lines))
# Sort blocks top-to-bottom, then left-to-right.
text_blocks.sort(key=lambda b: (b[0], b[1]))
block_texts = []
for _y0, _x0, lines in text_blocks:
line_texts = []
for line in lines:
spans = line.get("spans", [])
line_str = "".join(span.get("text", "") for span in spans)
line_texts.append(line_str)
block_str = "\n".join(line_texts).strip("\n")
if block_str.strip():
block_texts.append(block_str)
return "\n\n".join(block_texts)