scanlite 0.1.0

Cross-platform document scanner: crop, perspective-correct, enhance, OCR, and combine into PDF.

Scanlite

Turn photos of documents into clean, searchable PDFs.

Load scanned pages or photos from your phone, let Scanlite straighten, crop, and clean them automatically, reorder as needed, and export a single PDF with an optional OCR text layer.

Quick Start

pip install scanlite
scanlite

Or grab a native installer from Releases: .msi (Windows) · .dmg (macOS Apple Silicon) · .deb / .rpm (Linux)

Features

Import

• PDF (rendered at 200 DPI), PNG, JPG, TIFF, BMP, WebP
• Multi-page PDFs split into individual pages automatically
• Drag-and-drop support (when tkdnd is available)

Processing

• Auto-crop: Otsu threshold + contour detection trims to the document edge

• Auto-perspective: Canny edge detection finds a 4-point quadrilateral and warps it flat

• Scan enhance: three modes that produce a clean, scanner-like look:

  Mode	What it does
  auto	Detects page brightness; picks B&W for white pages, CLAHE for darker ones
  bw	Adaptive Gaussian threshold for pure black-on-white text
  gray	CLAHE contrast enhancement for photos or diagrams

• Every operation works per-page or as a batch across all pages

• Reset any page to its original at any time

Reorder and Manage

• Move Up / Move Down (or arrow keys) to reorder
• Delete to remove a page
• Thumbnail panel shows the current page order at a glance

Export

• PDF: combines all pages into a single document
• PDF + OCR: Tesseract generates an invisible text layer per page, making the output searchable and copy-pasteable
• Keyboard shortcuts: Ctrl+S export, Ctrl+Shift+S export with OCR

Installation

pip (all platforms)

pip install scanlite
scanlite          # launch the GUI

Native installers

Download from Releases:

Platform	File	Install
Windows x64	Scanlite-x.y.z.msi	Double-click; installs to Program Files with Start Menu shortcut
macOS ARM64	Scanlite-x.y.z.dmg	Open, drag to Applications
Debian/Ubuntu	scanlite-x.y.z.deb	sudo dpkg -i scanlite-x.y.z.deb
Fedora/RHEL	scanlite-x.y.z.rpm	sudo rpm -i scanlite-x.y.z.rpm

OCR dependency

OCR export requires Tesseract installed separately:

# Windows (winget)
winget install UB-Mannheim.TesseractOCR

# macOS
brew install tesseract

# Debian/Ubuntu
sudo apt install tesseract-ocr

# Fedora
sudo dnf install tesseract

The app works fine without Tesseract; you just cannot use the "Export PDF + OCR" button.

Keyboard Shortcuts

Key	Action
Ctrl+O	Import files
Up / Down	Navigate pages
Delete	Remove selected page
Ctrl+S	Export PDF
Ctrl+Shift+S	Export PDF + OCR

How It Works

Scanlite's processing pipeline runs perspective correction first (to avoid cropping a skewed quad), then crop, then enhancement. Each step is independent and can be applied or skipped per page.

The perspective detector looks for the largest 4-sided contour in the edge map and computes a homography to warp it into a rectangle. If no quadrilateral is found, the image passes through unchanged.

The scan enhancer auto-detects whether a page is mostly white (median brightness > 170) and picks adaptive thresholding for text-heavy pages or CLAHE for photos and diagrams.

System Requirements

• Python 3.10+
• Tesseract OCR (optional, for searchable PDF export)

Support

"Software is like sex: it's better when it's free." -- Linus Torvalds

If this tool saved you a trip to the copy shop, buying me a coffee is a nice way to say thanks.

License

MIT (see LICENSE.md)

Citation

@software{scanlite,
  author = {Colling, Gilles},
  title = {Scanlite: Cross-Platform Document Scanner},
  year = {2026},
  url = {https://github.com/gcol33/scanlite}
}