###### (This is the legacy documentation for stable SDL2, the current stable version; [SDL3](https://wiki.libsdl.org/SDL3/) is the current development version.) # SDL_SetWindowOpacity Set the opacity for a window. ## Syntax ```c int SDL_SetWindowOpacity(SDL_Window * window, float opacity); ``` ## Function Parameters | | | | --------------- | ----------------------------------------------------- | | **window** | the window which will be made transparent or opaque | | **opacity** | the opacity value (0.0f - transparent, 1.0f - opaque) | ## Return Value Returns 0 on success or a negative error code on failure; call [SDL_GetError](SDL_GetError)() for more information. ## Remarks The parameter `opacity` will be clamped internally between 0.0f (transparent) and 1.0f (opaque). This function also returns -1 if setting the opacity isn't supported. ## Version This function is available since SDL 2.0.5. ## Related Functions * [SDL_GetWindowOpacity](SDL_GetWindowOpacity) ---- [CategoryAPI](CategoryAPI)