SDL_PenAxisEvent.3type - Man Page

Defined in SDL3/SDL_events.h

#include "SDL3/SDL.h"

typedef struct SDL_PenAxisEvent
{
    SDL_EventType type;     /**< SDL_EVENT_PEN_AXIS */
    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_PenAxis axis;       /**< Axis that has changed */
    float value;            /**< New value of axis */
} SDL_PenAxisEvent;

You might get some of these events even if the pen isn't touching the tablet.

This struct is available since SDL 3.2.0.