SDL_gesture.h ------------- The Gesture API was removed from SDL3. As a migration path they provided an equivalent single-header library `SDL_gesture.h` that can be dropped into an SDL3-based project. They do not make formal releases of this code; they say "just grab the latest and drop it into your project!" The origin of this file is fork https://github.com/MarkCallow/SDL_gesture.git whose upstream is https://github.com/libsdl-org/SDL_gesture. It includes modifications for robustness to prevent production of spurious GESTURE\_MULTIGESTURE events.