1<HTML 2><HEAD 3><TITLE 4>SDL_SetGammaRamp</TITLE 5><META 6NAME="GENERATOR" 7CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ 8"><LINK 9REL="HOME" 10TITLE="SDL Library Documentation" 11HREF="index.html"><LINK 12REL="UP" 13TITLE="Video" 14HREF="video.html"><LINK 15REL="PREVIOUS" 16TITLE="SDL_GetGammaRamp" 17HREF="sdlgetgammaramp.html"><LINK 18REL="NEXT" 19TITLE="SDL_MapRGB" 20HREF="sdlmaprgb.html"></HEAD 21><BODY 22CLASS="REFENTRY" 23BGCOLOR="#FFF8DC" 24TEXT="#000000" 25LINK="#0000ee" 26VLINK="#551a8b" 27ALINK="#ff0000" 28><DIV 29CLASS="NAVHEADER" 30><TABLE 31SUMMARY="Header navigation table" 32WIDTH="100%" 33BORDER="0" 34CELLPADDING="0" 35CELLSPACING="0" 36><TR 37><TH 38COLSPAN="3" 39ALIGN="center" 40>SDL Library Documentation</TH 41></TR 42><TR 43><TD 44WIDTH="10%" 45ALIGN="left" 46VALIGN="bottom" 47><A 48HREF="sdlgetgammaramp.html" 49ACCESSKEY="P" 50>Prev</A 51></TD 52><TD 53WIDTH="80%" 54ALIGN="center" 55VALIGN="bottom" 56></TD 57><TD 58WIDTH="10%" 59ALIGN="right" 60VALIGN="bottom" 61><A 62HREF="sdlmaprgb.html" 63ACCESSKEY="N" 64>Next</A 65></TD 66></TR 67></TABLE 68><HR 69ALIGN="LEFT" 70WIDTH="100%"></DIV 71><H1 72><A 73NAME="SDLSETGAMMARAMP" 74></A 75>SDL_SetGammaRamp</H1 76><DIV 77CLASS="REFNAMEDIV" 78><A 79NAME="AEN1624" 80></A 81><H2 82>Name</H2 83>SDL_SetGammaRamp -- Sets the color gamma lookup tables for the display</DIV 84><DIV 85CLASS="REFSYNOPSISDIV" 86><A 87NAME="AEN1627" 88></A 89><H2 90>Synopsis</H2 91><DIV 92CLASS="FUNCSYNOPSIS" 93><A 94NAME="AEN1628" 95></A 96><P 97></P 98><PRE 99CLASS="FUNCSYNOPSISINFO" 100>#include "SDL.h"</PRE 101><P 102><CODE 103><CODE 104CLASS="FUNCDEF" 105>int <B 106CLASS="FSFUNC" 107>SDL_SetGammaRamp</B 108></CODE 109>(Uint16 *redtable, Uint16 *greentable, Uint16 *bluetable);</CODE 110></P 111><P 112></P 113></DIV 114></DIV 115><DIV 116CLASS="REFSECT1" 117><A 118NAME="AEN1634" 119></A 120><H2 121>Description</H2 122><P 123>Sets the gamma lookup tables for the display for each color component. 124Each table is an array of 256 Uint16 values, representing a mapping 125between the input and output for that channel. The input is the index 126into the array, and the output is the 16-bit gamma value at that index, 127scaled to the output color precision. You may pass NULL to any of the 128channels to leave them unchanged.</P 129><P 130>This function adjusts the gamma based on lookup tables, you can also 131have the gamma calculated based on a "gamma function" parameter with 132<A 133HREF="sdlsetgamma.html" 134>SDL_SetGamma</A 135>.</P 136><P 137>Not all display hardware is able to change gamma.</P 138></DIV 139><DIV 140CLASS="REFSECT1" 141><A 142NAME="AEN1640" 143></A 144><H2 145>Return Value</H2 146><P 147>Returns -1 on error (or if gamma adjustment is not supported).</P 148></DIV 149><DIV 150CLASS="REFSECT1" 151><A 152NAME="AEN1643" 153></A 154><H2 155>See Also</H2 156><P 157><A 158HREF="sdlsetgamma.html" 159>SDL_SetGamma</A 160> 161<A 162HREF="sdlgetgammaramp.html" 163>SDL_GetGammaRamp</A 164></P 165></DIV 166><DIV 167CLASS="NAVFOOTER" 168><HR 169ALIGN="LEFT" 170WIDTH="100%"><TABLE 171SUMMARY="Footer navigation table" 172WIDTH="100%" 173BORDER="0" 174CELLPADDING="0" 175CELLSPACING="0" 176><TR 177><TD 178WIDTH="33%" 179ALIGN="left" 180VALIGN="top" 181><A 182HREF="sdlgetgammaramp.html" 183ACCESSKEY="P" 184>Prev</A 185></TD 186><TD 187WIDTH="34%" 188ALIGN="center" 189VALIGN="top" 190><A 191HREF="index.html" 192ACCESSKEY="H" 193>Home</A 194></TD 195><TD 196WIDTH="33%" 197ALIGN="right" 198VALIGN="top" 199><A 200HREF="sdlmaprgb.html" 201ACCESSKEY="N" 202>Next</A 203></TD 204></TR 205><TR 206><TD 207WIDTH="33%" 208ALIGN="left" 209VALIGN="top" 210>SDL_GetGammaRamp</TD 211><TD 212WIDTH="34%" 213ALIGN="center" 214VALIGN="top" 215><A 216HREF="video.html" 217ACCESSKEY="U" 218>Up</A 219></TD 220><TD 221WIDTH="33%" 222ALIGN="right" 223VALIGN="top" 224>SDL_MapRGB</TD 225></TR 226></TABLE 227></DIV 228></BODY 229></HTML 230>