(This is the legacy documentation for SDL2, the previous stable version; SDL3 is the current stable version.)

SDL_PremultiplyAlpha

Premultiply the alpha on a block of pixels.

Header File

Defined in SDL_surface.h

Syntax

int SDL_PremultiplyAlpha(int width, int height,
                         Uint32 src_format,
                         const void * src, int src_pitch,
                         Uint32 dst_format,
                         void * dst, int dst_pitch);

Function Parameters

int	width	the width of the block to convert, in pixels.
int	height	the height of the block to convert, in pixels.
Uint32	src_format	an SDL_PixelFormatEnum value of the src pixels format.
const void *	src	a pointer to the source pixels.
int	src_pitch	the pitch of the source pixels, in bytes.
Uint32	dst_format	an SDL_PixelFormatEnum value of the dst pixels format.
void *	dst	a pointer to be filled in with premultiplied pixel data.
int	dst_pitch	the pitch of the destination pixels, in bytes.

Return Value

(int) Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.

Remarks

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

This function is currently only implemented for SDL_PIXELFORMAT_ARGB8888.

Version

This function is available since SDL 2.0.18.

---

CategoryAPI, CategoryAPIFunction, CategorySurface

[ front page | index | search | recent changes | git repo | offline html ]

All wiki content is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0).
Wiki powered by ghwikipp.