Rasterbator

Rasterbator is a private, offline macOS app that turns a local image into a dimensionally accurate, multi-page A4 mosaic PDF. It preserves the image aspect ratio and adds configurable blank margins and vector cutting guides for trimming and assembly.

Features

• Imports PNG, JPEG, and WebP images, including EXIF orientation handling
• Sizes posters by retained sheet widths or linked physical dimensions
• Supports portrait and landscape A4 sheets
• Preserves source proportions with contain/cover fitting and alignment controls
• Configurable cutting margins, full-border or corner cutting guides, overlap, and page labels in the preview
• Poster and individual-sheet previews with page navigation and zoom controls
• 150, 200, or 300 DPI PDF output, plus an optional lossy compression mode
• Canonical Rust geometry shared by preview and export
• Local-only processing with no account, upload, analytics, or network service
• Atomic PDF output so an interrupted write does not leave a partial destination file

Install on macOS

Download the Apple Silicon .dmg from the latest release, open it, and drag Rasterbator into Applications.

The app is currently unsigned and not notarized. On first launch, macOS may block it. Open System Settings → Privacy & Security, find the Rasterbator message, choose Open Anyway, and confirm. Only install a build downloaded from this repository.

Print exported PDFs at Actual size / 100% with fit-to-page disabled.

Use

1. Choose or drop a PNG, JPEG, or WebP image.
2. Select poster dimensions, A4 orientation, fit, margins, guides, and output quality.
3. Inspect the full poster and individual sheet previews.
4. Choose Export PDF and select a destination.
5. Print at Actual size / 100%, trim on the inner guides, and assemble pages left-to-right and top-to-bottom.

Privacy

Rasterbator works entirely on the Mac. Images and generated PDFs are not uploaded anywhere, and the previous image is not automatically reopened on the next launch.

Requirements

• macOS on Apple Silicon for the provided v0.1.0 binary
• A PDF viewer and printer configured not to scale pages for physical output

Development

Prerequisites:

• Node.js and npm
• Rust 1.85 or newer
• The macOS prerequisites for Tauri 2

Install and run:

npm install
npm run tauri dev

Run all local quality gates and create a production bundle:

npm run check
npm run tauri build

Useful commands:

npm run check:fast    # frontend and Rust gates in parallel
npm run check:full    # fast gates plus production frontend build
npm run test          # frontend tests
npm run rust:test     # Rust tests
npm run build         # production frontend
npm run spike:pdf -- --output-dir benchmarks/results

Create a verified macOS release build from a clean tree whose package, Cargo, and Tauri versions already match:

npm run release:mac -- 0.1.1

After reviewing the generated DMG and checksum, publish the tag and GitHub release with:

npm run release:mac -- 0.1.1 --publish

Generated PDFs, build output, benchmark results, logs, and local source images are intentionally ignored by Git.

Architecture and documentation

The desktop shell uses Tauri 2 with a React/TypeScript interface. Rust owns image decoding, validation, physical geometry, rendering, and PDF generation. Start with:

• PLAN.md — scope, architecture, geometry, and milestones
• DESIGN.md — interface and accessibility design
• USER_FLOW.md — complete workflow and failure paths
• TESTS.md — automated and physical test strategy
• AGENTS.md — contributor guidance and project status

Release status

v0.1.0 is a personal MVP distributed as an unsigned Apple Silicon macOS build. Windows, Linux, Intel Mac binaries, signing/notarization, automatic updates, paper sizes other than A4, and image effects are not included.

This is private software. No license is granted for redistribution or modification.