###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!) # SDL_ISPIXELFORMAT_ALPHA A macro to determine if an [SDL_PixelFormat](SDL_PixelFormat) has an alpha channel. ## Header File Defined in [](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_pixels.h) ## Syntax ```c #define SDL_ISPIXELFORMAT_ALPHA(format) \ ((SDL_ISPIXELFORMAT_PACKED(format) && \ ((SDL_PIXELORDER(format) == SDL_PACKEDORDER_ARGB) || \ (SDL_PIXELORDER(format) == SDL_PACKEDORDER_RGBA) || \ (SDL_PIXELORDER(format) == SDL_PACKEDORDER_ABGR) || \ (SDL_PIXELORDER(format) == SDL_PACKEDORDER_BGRA))) || \ (SDL_ISPIXELFORMAT_ARRAY(format) && \ ((SDL_PIXELORDER(format) == SDL_ARRAYORDER_ARGB) || \ (SDL_PIXELORDER(format) == SDL_ARRAYORDER_RGBA) || \ (SDL_PIXELORDER(format) == SDL_ARRAYORDER_ABGR) || \ (SDL_PIXELORDER(format) == SDL_ARRAYORDER_BGRA)))) ``` ## Macro Parameters | | | | ---------- | ----------------------------------------------- | | **format** | an [SDL_PixelFormat](SDL_PixelFormat) to check. | ## Return Value Returns true if the format has alpha, false otherwise. ## Remarks Note that this macro double-evaluates its parameter, so do not use expressions with side-effects here. ## Thread Safety It is safe to call this macro from any thread. ## Version This macro is available since SDL 3.1.3. ---- [CategoryAPI](CategoryAPI), [CategoryAPIMacro](CategoryAPIMacro), [CategoryPixels](CategoryPixels)