redhat man page for sdl_setgammaramp

SDL_SetGammaRamp(3)						 SDL API Reference					       SDL_SetGammaRamp(3)

NAME
       SDL_SetGammaRamp- Sets the color gamma lookup tables for the display

SYNOPSIS
       #include "SDL.h"

       int SDL_SetGammaRamp(Uint16 *redtable, Uint16 *greentable, Uint16 *bluetable);

DESCRIPTION
       Sets  the gamma lookup tables for the display for each color component. Each table is an array of 256 Uint16 values, representing a mapping
       between the input and output for that channel. The input is the index into the array, and the output is the  16-bit  gamma  value  at  that
       index, scaled to the output color precision. You may pass NULL to any of the channels to leave them unchanged.

       This  function  adjusts the gamma based on lookup tables, you can also have the gamma calculated based on a "gamma function" parameter with
       SDL_SetGamma.

       Not all display hardware is able to change gamma.

RETURN VALUE
       Returns -1 on error (or if gamma adjustment is not supported).

SEE ALSO
       SDL_SetGamma SDL_GetGammaRamp

SDL
							      Tue 11 Sep 2001, 23:01					       SDL_SetGammaRamp(3)