SDL2/SDL_MouseWheelEvent

Defined in [SDL_events.h](https://github.com/libsdl-org/SDL/blob/SDL2/include/SDL_events.h), but apps should _only_ `#include "SDL.h"`!

Syntax

typedef struct SDL_MouseWheelEvent
{
    Uint32 type;        /**< ::SDL_MOUSEWHEEL */
    Uint32 timestamp;   /**< In milliseconds, populated using SDL_GetTicks() */
    Uint32 windowID;    /**< The window with mouse focus, if any */
    Uint32 which;       /**< The mouse instance id, or SDL_TOUCH_MOUSEID */
    Sint32 x;           /**< The amount scrolled horizontally, positive to the right and negative to the left */
    Sint32 y;           /**< The amount scrolled vertically, positive away from the user and negative toward the user */
    Uint32 direction;   /**< Set to one of the SDL_MOUSEWHEEL_* defines. When FLIPPED the values in X and Y will be opposite. Multiply by -1 to change them back */
    float preciseX;     /**< The amount scrolled horizontally, positive to the right and negative to the left, with float precision (added in 2.0.18) */
    float preciseY;     /**< The amount scrolled vertically, positive away from the user and negative toward the user, with float precision (added in 2.0.18) */
    Sint32 mouseX;      /**< X coordinate, relative to window (added in 2.26.0) */
    Sint32 mouseY;      /**< Y coordinate, relative to window (added in 2.26.0) */
} SDL_MouseWheelEvent;

Code Examples


SDL_Event event;
while( SDL_PollEvent( &event ) )
{
    if(event.type == SDL_MOUSEWHEEL)
    {
        if(event.wheel.y > 0) // scroll up
        {
             // Put code for handling "scroll up" here!
        }
        else if(event.wheel.y < 0) // scroll down
        {
             // Put code for handling "scroll down" here!
        }

        if(event.wheel.x > 0) // scroll right
        {
             // ...
        }
        else if(event.wheel.x < 0) // scroll left
        {
             // ...
        }
    }
    else if(event.type == SDL_MOUSEBUTTONDOWN)
    {
        // ... handle mouse clicks ...
    }

    // ... handle other kinds of events ...
}

Uint32	type	SDL_MOUSEWHEEL
Uint32	timestamp	timestamp of the event
Uint32	windowID	the window with mouse focus, if any
Uint32	which	the mouse instance id, or SDL_TOUCH_MOUSEID; see Remarks for details
Sint32	x	the amount scrolled horizontally, positive to the right and negative to the left
Sint32	y	the amount scrolled vertically, positive away from the user and negative towards the user
Uint32	direction	SDL_MOUSEWHEEL_NORMAL or SDL_MOUSEWHEEL_FLIPPED; see Remarks for details (>= SDL 2.0.4)
float	preciseX	the amount scrolled horizontally, positive to the right and negative to the left, with float precision (added in 2.0.18)
float	preciseY	the amount scrolled vertically, positive away from the user and negative toward the user, with float precision (added in 2.0.18)

(This is the legacy documentation for stable SDL2, the current stable version; SDL3 is the current development version.)

SDL_MouseWheelEvent

Header File

Syntax

Code Examples

Data Fields

Related Enumerations

Related Structures