SDL_PenMotionEvent.3type - Man Page

Defined in SDL3/SDL_events.h

#include "SDL3/SDL.h"

typedef struct SDL_PenMotionEvent
{
    SDL_EventType type; /**< SDL_EVENT_PEN_MOTION */
    Uint32 reserved;
    Uint64 timestamp;   /**< In nanoseconds, populated using SDL_GetTicksNS() */
    SDL_WindowID windowID; /**< The window with pen focus, if any */
    SDL_PenID which;        /**< The pen instance id */
    SDL_PenInputFlags pen_state;   /**< Complete pen input state at time of event */
    float x;                /**< X coordinate, relative to window */
    float y;                /**< Y coordinate, relative to window */
} SDL_PenMotionEvent;

Depending on the hardware, you may get motion events when the pen is not touching a tablet, for tracking a pen even when it isn't drawing. You should listen for SDL_EVENT_PEN_DOWN
and

SDL_EVENT_PEN_UP
events, or check pen_state& SDL_PEN_INPUT_DOWN to decide if a pen is "drawing" when dealing with pen motion.

This struct is available since SDL 3.2.0.