NAME

SDL_PremultiplyAlpha - Premultiply the alpha on a block of pixels.

SYNOPSIS

#include <SDL3/SDL_surface.h>

bool SDL_PremultiplyAlpha(int width, int height, SDL_PixelFormat src_format, const void *src, int src_pitch, SDL_PixelFormat dst_format, void *dst, int dst_pitch, bool linear);

DESCRIPTION

This is safe to use with src == dst, but not for other overlapping areas.

FUNCTION PARAMETERS

width

the width of the block to convert, in pixels.

height

the height of the block to convert, in pixels.

src_format

an SDL_PixelFormat value of the src pixels format.

src

a pointer to the source pixels.

src_pitch

the pitch of the source pixels, in bytes.

dst_format

an SDL_PixelFormat value of the dst pixels format.

dst

a pointer to be filled in with premultiplied pixel data.

dst_pitch

the pitch of the destination pixels, in bytes.

linear

true to convert from sRGB to linear space for the alpha multiplication, false to do multiplication in sRGB space.

RETURN VALUE

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

THREAD SAFETY

The same destination pixels should not be used from two threads at once. It is safe to use the same source pixels from multiple threads.

AVAILABILITY

This function is available since SDL 3.2.0.