(This is the documentation for SDL3, which is the current stable version. SDL2 was the previous version!)

SDL_SetWindowAspectRatio

Request that the aspect ratio of a window's client area be set.

Header File

Syntax

bool SDL_SetWindowAspectRatio(SDL_Window *window, float min_aspect, float max_aspect);

Function Parameters

SDL_Window *	window	the window to change.
float	min_aspect	the minimum aspect ratio of the window, or 0.0f for no limit.
float	max_aspect	the maximum aspect ratio of the window, or 0.0f for no limit.

Return Value

(bool) Returns true on success or false on failure; call SDL_GetError() for more information.

Remarks

The aspect ratio is the ratio of width divided by height, e.g. 2560x1600 would be 1.6. Larger aspect ratios are wider and smaller aspect ratios are narrower.

If, at the time of this request, the window in a fixed-size state, such as maximized or fullscreen, the request will be deferred until the window exits this state and becomes resizable again.

On some windowing systems, this request is asynchronous and the new window aspect ratio may not have have been applied immediately upon the return of this function. If an immediate change is required, call SDL_SyncWindow() to block until the changes have taken effect.

When the window size changes, an SDL_EVENT_WINDOW_RESIZED event will be emitted with the new window dimensions. Note that the new dimensions may not match the exact aspect ratio requested, as some windowing systems can restrict the window size in certain scenarios (e.g. constraining the size of the content area to remain within the usable desktop bounds). Additionally, as this is just a request, it can be denied by the windowing system.

Thread Safety

This function should only be called on the main thread.

Version

This function is available since SDL 3.1.3.