GitHub - overflowy/make-look-scanned: Makes PDFs look scanned (CLI or in the browser via WASM)

A CLI that takes a PDF and degrades it to look like a physical scan of a printout — skew, grayscale, warm paper tone, scanner grain, defocus, edge shadow, and JPEG compression artifacts. Also runs client-side in the browser via WASM.

Each page is rasterized to an image, run through the effect pipeline, and reassembled into a new image-only PDF (the original selectable text is gone — faithful to a basic scanner). Build Requires Go and a C toolchain (go-fitz links MuPDF via cgo, so the binary is self-contained — nothing to install at runtime). go build -o make-look-scanned . Usage make-look-scanned [flags] input.pdf Flags may appear before or after the input filename. make-look-scanned in.pdf # -> in.scanned.pdf make-look-scanned in.pdf -o out.pdf make-look-scanned in.pdf --noise 0.4 --skew 2.5 --jpeg-quality 30 Flags

Flag Default Meaning

-o <input>.scanned.pdf output path

--preset — named preset from config.toml

--seed content hash random seed (override for a new look)

--force false overwrite an existing output file

--dpi 150 render resolution

--skew 0.6 max rotation degrees (0 disables)

--grayscale true desaturate (--grayscale=false keeps color)

--paper-tone 0.6 warm paper tint strength 0..1

--noise 0.08 scanner grain 0..1

--blur 0.4 defocus gaussian sigma

--edge-shadow 0.15 border vignette 0..1

--jpeg-quality 70 JPEG quality 1..100

Each numeric knob disables its effect at 0. Determinism Output is deterministic by default: the seed is derived from the input PDF's content, so the same file always produces the same scan. Pass --seed N for a different (but reproducible) look. Same input + seed yields a byte-identical PDF.

Presets Define reusable bundles in $XDG_CONFIG_HOME/make-look-scanned/config.toml (falls back to ~/.make-look-scanned/config.toml when XDG_CONFIG_HOME is unset). Keys mirror the flag names with underscores: [presets.medium] skew = 1.5 paper_tone = 0.6 noise = 0.2 blur = 0.6 edge_shadow = 0.3 jpeg_quality = 45 make-look-scanned --preset medium in.pdf Precedence: built-in defaults → selected preset → explicit CLI flags (flags always win). Browser (WebAssembly) The effect pipeline also runs in the browser. go-fitz/MuPDF can't compile to wasm, so the browser uses PDF.js to rasterize pages and hands the pixels to the same Go effects + assembly code compiled to wasm. Dev (needs network for the PDF.js CDN): ./web/build.sh # builds web/main.wasm + wasm_exec.js (cd web && python3 -m http.server 8080) # then open http://localhost:8080 Single self-contained file (works offline, nothing to serve): task build:web # writes dist/make-look-scanned.html (~8 MB) dist/make-look-scanned.html inlines the wasm, Go's runtime glue, and PDF.js (library + worker) as base64 — open it directly in a browser. Output is visually equivalent to the CLI but not byte-identical, since PDF.js and MuPDF rasterize differently. License AGPL-3.0. The CLI statically links MuPDF (via go-fitz), which is AGPL-3.0, so the combined binary is AGPL-3.0 — distributing it requires offering the corresponding source. The browser build does not include MuPDF (it uses PDF.js, Apache-2.0).