gexedit map editor for Gex GBC disassemblies

gexedit is a map editor designed for the Gex Game Boy Color disassemblies, specifically Gex: Enter the Gecko and Gex 3: Deep Cover Gecko. The tool provides a unified interface for both games, with game-specific differences managed through JSON profiles. The editor supports map viewing, block painting, and object manipulation, including entities, collectibles, and doors. It reads object schemas directly from the disassembly's existing tools/map_formats.json files to ensure consistency with the ROM build process. The author reports that the editor handles complex game logic, such as Gex 2's two-way door pairs, by automatically updating reverse partners when a door is moved. Rendering tests verify the Gex 2 pipeline against known-good output. The project credits Claude Opus 5 as a co-author for various implementation tasks, including object editing, door marker positioning, and test suite optimization. While the editor achieves high fidelity, the author notes that 8 Media Dimension blocks in Gex 2 remain distinct from the reference rendering due to their use of multiple television palettes. gexedit requires Python 3.8+, Pillow, numpy, and Tk.