---
name: "SDL_DisplayFormatAlpha"
section: "3"
platform: "linux"
package: "libsdl1.2-dev"
version: "1.2.15+dfsg2-8"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/SDL_DisplayFormatAlpha"
---

# SDL\_DisplayFormatAlpha(3)

Convert a surface to the display format

## NAME

SDL\_DisplayFormatAlpha - Convert a surface to the display format

## SYNOPSIS

**#include "SDL.h"**

**SDL\_Surface \*SDL\_DisplayFormatAlpha**(**SDL\_Surface \*surface**);

## DESCRIPTION

This function takes a surface and copies it to a new surface of the pixel format and colors of the video framebuffer plus an alpha channel, suitable for fast blitting onto the display surface. It calls *SDL\_ConvertSurface*

If you want to take advantage of hardware colorkey or alpha blit acceleration, you should set the colorkey and alpha value before calling this function.

This function can be used to convert a colourkey to an alpha channel, if the **SDL\_SRCCOLORKEY** flag is set on the surface. The generated surface will then be transparent (alpha=0) where the pixels match the colourkey, and opaque (alpha=255) elsewhere.

## RETURN VALUE

If the conversion fails or runs out of memory, it returns **NULL**

## SEE ALSO

*SDL\_ConvertSurface*, *SDL\_SetAlpha*, *SDL\_SetColorKey*, *SDL\_DisplayFormat*, *SDL\_Surface*