77 lines
2.6 KiB
Python
77 lines
2.6 KiB
Python
"""Shared page rasterizer with a fallback chain: pypdfium2 -> pdftoppm.
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Returns PIL Images so callers can annotate/save. Not a CLI.
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"""
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from __future__ import annotations
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import shutil
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import subprocess
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import tempfile
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from pathlib import Path
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def available_backends() -> list[str]:
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"""Names of usable rasterizer backends, in preference order."""
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backends = []
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try:
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import pypdfium2 # noqa: F401
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backends.append("pypdfium2")
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except ImportError:
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pass
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if shutil.which("pdftoppm"):
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backends.append("pdftoppm")
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return backends
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def missing_hints() -> list[str]:
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"""Install hints for when no backend is available."""
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return [
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"python3 -m pip install pypdfium2",
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"poppler-utils (provides pdftoppm), e.g. apt-get install poppler-utils",
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]
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def rasterize_page(pdf_path: str, page: int, dpi: int = 150, password: str | None = None):
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"""Render one 1-based page to a PIL Image, or None if no backend works.
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Raises ValueError for an out-of-range page when a backend is present.
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"""
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for backend in available_backends():
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if backend == "pypdfium2":
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return _via_pdfium(pdf_path, page, dpi, password)
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if backend == "pdftoppm":
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img = _via_pdftoppm(pdf_path, page, dpi, password)
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if img is not None:
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return img
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return None
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def _via_pdfium(pdf_path: str, page: int, dpi: int, password: str | None):
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import pypdfium2 as pdfium
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doc = pdfium.PdfDocument(pdf_path, password=password)
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try:
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if not 1 <= page <= len(doc):
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raise ValueError(f"page {page} out of range 1-{len(doc)}")
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bitmap = doc[page - 1].render(scale=dpi / 72.0)
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return bitmap.to_pil().convert("RGB")
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finally:
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doc.close()
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def _via_pdftoppm(pdf_path: str, page: int, dpi: int, password: str | None):
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from PIL import Image
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with tempfile.TemporaryDirectory() as tmp:
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prefix = str(Path(tmp) / "page")
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cmd = ["pdftoppm", "-png", "-r", str(dpi), "-f", str(page), "-l", str(page)]
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if password:
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cmd += ["-upw", password]
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cmd += [pdf_path, prefix]
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proc = subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8")
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if proc.returncode != 0:
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raise ValueError(f"pdftoppm failed: {proc.stderr.strip()}")
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produced = sorted(Path(tmp).glob("page*.png"))
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if not produced:
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raise ValueError(f"page {page} out of range (pdftoppm produced no image)")
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with Image.open(produced[0]) as img:
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return img.convert("RGB")
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