view docs/man3/SDL_SetGammaRamp.3 @ 1626:a80e1e0880b8

Fixed bug #176 [I'm fixing this for the public headers, but I'm not going to bother for the SDL library code (yet)] To clarify: Normaly, GCC (or, to be precise, the preprocessor) will ignore this, and compile the code happily. However, one can specify -Wundef to get a warning about this. One can probably argue whether to consider this a bug or not; but I think that (a) from a semantic point of view, using "#if FOO" when FOO is not defined is strange, and (b) since it is possible to trigger a warning about this, and a trivial fix exists, it should be corrected. I can think of two alternative patches, BTW: 1) Simply use #define HAVE_FOO 0, instead of not defining HAVE_FOO at all 2) Change #if HAVE_FOO to #if HAVE_FOO+0 which always does the right thing. But I think I still prefer the attached patch :-).
author Sam Lantinga <slouken@libsdl.org>
date Thu, 13 Apr 2006 13:38:40 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_SetGammaRamp" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_SetGammaRamp\- Sets the color gamma lookup tables for the display
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_SetGammaRamp\fP\fR(\fBUint16 *redtable, Uint16 *greentable, Uint16 *bluetable\fR);
.SH "DESCRIPTION"
.PP
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\&.
.PP
This function adjusts the gamma based on lookup tables, you can also have the gamma calculated based on a "gamma function" parameter with \fISDL_SetGamma\fR\&.
.PP
Not all display hardware is able to change gamma\&.
.SH "RETURN VALUE"
.PP
Returns -1 on error (or if gamma adjustment is not supported)\&.
.SH "SEE ALSO"
.PP
\fISDL_SetGamma\fR \fISDL_GetGammaRamp\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01