scanlayer
Docs / Guides

Multi-Page and Merge

Two related but different things: converting many separate files in one call (batch), and combining several pages into a single multi-page PDF (merge). A native PDF as input touches both.

Batch conversion

Multiple inputs plus a folder as -o converts each file independently, one output per input.

bash 
scanlayer *.jpg -o ./converted/
pythonbatch.py 
result = scanlayer.convert_batch(["*.jpg"], "./converted/")

A single bad file does not abort the batch. CLI exit code 5 signals a partial failure; in the library, check BatchResult.failures. See Library API → convert_batch().

--merge: one PDF from many pages

bash 
scanlayer a.jpg b.jpg -o combined.pdf --merge
pythonmerge.py 
scanlayer.convert_merge(["a.jpg", "b.jpg"], "combined.pdf")

Combines multiple images into one multi-page PDF, in argument order.

PDF-only --merge only supports --format pdf / output_format="pdf", since there is no single sensible multi-page schema for txt/json/tsv/hocr. -o / output_path must be a file path, not a folder, when merging.

Native PDF input

A .pdf file given as input is automatically rasterized page by page (via pdf2image/poppler) before OCR.

With --mergeWithout --merge
Re-runs OCR over an existing PDF and gets one PDF back out.Gets one output file per source page.
Requires poppler on PATH See Installation. If it is missing, scanlayer raises DependencyError with an actionable message rather than a cryptic subprocess failure.
bash 
# one output file per page
scanlayer scanned-report.pdf -o ./pages/

# re-OCR the whole document into a single merged PDF
scanlayer scanned-report.pdf -o ocred-report.pdf --merge
pythonpdf_input.py 
scanlayer.convert_batch(["scanned-report.pdf"], "./pages/")

# merge=True on convert_batch goes straight from a PDF's pages
# to one merged, re-OCR'd PDF:
scanlayer.convert_batch(
    ["scanned-report.pdf"], "ocred-report.pdf", merge=True,
)
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