Paint.NET Developer Uses Claude to Rewrite Direct2D for Linux WINE Support
Paint.NET creator Rick Brewster used Anthropic's Claude to produce a 180,000-line managed, clean-room implementation of Microsoft's Direct2D API. This new managed DLL enables experimental Linux support for Paint.NET via WINE by bypassing WINE's incomplete native Direct2D implementation. This project demonstrates a practical application of AI coding agents to solve complex legacy compatibility hurdles that single human developers previously found unfeasible to address. It highlights how LLMs can accelerate large-scale software re-implementation and reverse engineering, potentially accelerating cross-platform software porting. Brewster described the codebase as heavily "vibe coded," noting that while Claude performed impressive reverse engineering to determine formulas for Direct2D's effect library, it required significant supervision for low-level memory management like COM reference counting. The new managed assembly, `PaintDotNet.Windows.Direct2D1.Managed.dll`, is enabled using the `/wine` command-line switch.
## BACKGROUND
Direct2D is a hardware-accelerated 2D vector graphics API developed by Microsoft for Windows applications. WINE is an open-source compatibility layer designed to let Windows applications run on Unix-like operating systems such as Linux, but its implementation of Direct2D has long lacked full compatibility with Paint.NET. Clean-room design is a technique used to reverse-engineer and recreate a system's functionality from scratch without infringing on the copyrighted source code of the original implementation.