pdf

1"""Shared page rasterizer with a fallback chain: pypdfium2 -> pdftoppm.2 3Returns PIL Images so callers can annotate/save. Not a CLI.4"""5from __future__ import annotations6 7import shutil8import subprocess9import tempfile10from pathlib import Path11 12 13def available_backends() -> list[str]:14    """Names of usable rasterizer backends, in preference order."""15    backends = []16    try:17        import pypdfium2  # noqa: F40118        backends.append("pypdfium2")19    except ImportError:20        pass21    if shutil.which("pdftoppm"):22        backends.append("pdftoppm")23    return backends24 25 26def missing_hints() -> list[str]:27    """Install hints for when no backend is available."""28    return [29        "python3 -m pip install pypdfium2",30        "poppler-utils (provides pdftoppm), e.g. apt-get install poppler-utils",31    ]32 33 34def rasterize_page(pdf_path: str, page: int, dpi: int = 150, password: str | None = None):35    """Render one 1-based page to a PIL Image, or None if no backend works.36 37    Raises ValueError for an out-of-range page when a backend is present.38    """39    for backend in available_backends():40        if backend == "pypdfium2":41            return _via_pdfium(pdf_path, page, dpi, password)42        if backend == "pdftoppm":43            img = _via_pdftoppm(pdf_path, page, dpi, password)44            if img is not None:45                return img46    return None47 48 49def _via_pdfium(pdf_path: str, page: int, dpi: int, password: str | None):50    import pypdfium2 as pdfium51    doc = pdfium.PdfDocument(pdf_path, password=password)52    try:53        if not 1 <= page <= len(doc):54            raise ValueError(f"page {page} out of range 1-{len(doc)}")55        bitmap = doc[page - 1].render(scale=dpi / 72.0)56        return bitmap.to_pil().convert("RGB")57    finally:58        doc.close()59 60 61def _via_pdftoppm(pdf_path: str, page: int, dpi: int, password: str | None):62    from PIL import Image63    with tempfile.TemporaryDirectory() as tmp:64        prefix = str(Path(tmp) / "page")65        cmd = ["pdftoppm", "-png", "-r", str(dpi), "-f", str(page), "-l", str(page)]66        if password:67            cmd += ["-upw", password]68        cmd += [pdf_path, prefix]69        proc = subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8")70        if proc.returncode != 0:71            raise ValueError(f"pdftoppm failed: {proc.stderr.strip()}")72        produced = sorted(Path(tmp).glob("page*.png"))73        if not produced:74            raise ValueError(f"page {page} out of range (pdftoppm produced no image)")75        with Image.open(produced[0]) as img:76            return img.convert("RGB")77