fontbm is a cross-platform command-line tool for generating BMFont-compatible bitmap fonts from TrueType/OpenType fonts using FreeType2. The application parses command-line options, renders glyphs, packs them into texture atlases using MaxRectsBinPack, and outputs font metrics in multiple formats (text, XML, binary, JSON) along with PNG texture pages. The architecture is modular with clear separation of concerns: option parsing, FreeType handling, glyph packing, rendering, and output formatting. While the core logic is specific to font bitmap generation, several utility components demonstrate reusable patterns.