Dollar Gesture Event (event.dgesture.*)
Defined in SDL_events.h
typedef struct SDL_DollarGestureEvent
{
Uint32 type; /**< SDL_DOLLARGESTURE or SDL_DOLLARRECORD */
Uint32 timestamp; /**< In milliseconds, populated using SDL_GetTicks() */
SDL_TouchID touchId; /**< The touch device id */
SDL_GestureID gestureId;
Uint32 numFingers;
float error;
float x; /**< Normalized center of gesture */
float y; /**< Normalized center of gesture */
} SDL_DollarGestureEvent;