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

SDL_GetRGBA

Get RGBA values from a pixel in the specified format.

Header File

Syntax

void SDL_GetRGBA(Uint32 pixel, const SDL_PixelFormatDetails *format, const SDL_Palette *palette, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);

Function Parameters

Uint32	pixel	a pixel value.
const SDL_PixelFormatDetails *	format	a pointer to SDL_PixelFormatDetails describing the pixel format.
const SDL_Palette *	palette	an optional palette for indexed formats, may be NULL.
Uint8 *	r	a pointer filled in with the red component, may be NULL.
Uint8 *	g	a pointer filled in with the green component, may be NULL.
Uint8 *	b	a pointer filled in with the blue component, may be NULL.
Uint8 *	a	a pointer filled in with the alpha component, may be NULL.

Remarks

This function uses the entire 8-bit [0..255] range when converting color components from pixel formats with less than 8-bits per RGB component (e.g., a completely white pixel in 16-bit RGB565 format would return [0xff, 0xff, 0xff] not [0xf8, 0xfc, 0xf8]).

If the surface has no alpha component, the alpha will be returned as 0xff (100% opaque).

Thread Safety

It is safe to call this function from any thread, as long as the palette is not modified.

Version

This function is available since SDL 3.1.3.