Xournal++ — Open-Source Handwriting and PDF Annotation App

Introduction

Xournal++ is a handwriting notetaking application designed for stylus and pen tablet input. It supports PDF annotation, LaTeX rendering, and audio recording, making it a versatile tool for students, researchers, and anyone who prefers handwritten notes on a digital canvas.

What Xournal++ Does

• Takes handwritten notes with pressure-sensitive pen and stylus support
• Annotates existing PDF documents with highlights, text, and drawings
• Renders LaTeX equations inline within handwritten notes
• Records and links audio to specific points in your notes for lecture review
• Exports pages as PDF, PNG, or SVG for sharing and archiving

Architecture Overview

Xournal++ is written in C++ using GTK3 for the user interface. The rendering pipeline supports pressure sensitivity, tilt detection, and low-latency stroke rendering for a natural writing feel. Documents are stored in a custom XML-based format (.xopp) that preserves layers, strokes, and embedded elements. PDF background rendering uses the Poppler library, and LaTeX support invokes a local TeX installation to generate inline formulas.

Self-Hosting & Configuration

• Install via system package managers, Flatpak, Snap, or downloadable installers
• Configure pen, eraser, and highlighter tool presets with custom colors and widths
• Set up drawing recognition to convert rough shapes into clean geometric forms
• Map tablet buttons to specific tools using the built-in input device configuration
• Customize page templates with different background styles including lined, grid, and graph paper

Key Features

• Pressure-sensitive pen input with sub-pixel stroke rendering for natural handwriting
• PDF annotation mode that overlays notes on existing documents without modifying the original
• Layer system for organizing content and separating handwriting from diagrams
• Plugin system using Lua scripting for custom tools and automation
• Cross-platform support for Linux, Windows, and macOS

Comparison with Similar Tools

• OneNote — cloud-dependent and proprietary; Xournal++ is offline-first and open-source
• Notability — iPad-only; Xournal++ runs on desktop with any pen tablet
• GoodNotes — Apple ecosystem only; Xournal++ is cross-platform and free
• Rnote — newer Rust-based alternative with fewer features; Xournal++ is more mature
• Write (Stylus Labs) — similar concept but less actively maintained; Xournal++ has a larger community

FAQ

Q: Does Xournal++ work with a mouse? A: Yes, but it is designed for stylus input. Mouse drawing works for basic annotation.

Q: Can I fill out PDF forms? A: Xournal++ is an annotation tool, not a form filler. You can draw and type over PDF pages but not interact with form fields.

Q: What file format does it use? A: The native format is .xopp (gzipped XML). You can export to PDF, PNG, or SVG.

Q: Does it support handwriting recognition? A: Not built-in. It focuses on preserving handwritten strokes. Shape recognition converts rough shapes to clean geometry.

Sources

• https://github.com/xournalpp/xournalpp
• https://xournalpp.github.io