MAN page from RedHat Other XITE-3.3-3.i386.rpm

GAMMAADJUST

Section: C Library Functions (3)
Updated: 16 Mar 1998
Index

NAME

gammaAdjust - Simple gamma correction

SYNTAX

#include <xite/histo.h>

BiffStatus gammaAdjust( IBAND inband,
IBAND outband, double adjust );

DESCRIPTION

A simple gamma corretion to make imagesdarker or brigter. The adjustparameter must bein the range -1.0 (much darker) to 1 (much brighter).If adjust = 0.0 the band is not changed.

If adjust > 0:
a= adjust**2/0.16;
b= 255.0 / log(a*255.0+1.0);
c= 256.0/a * log(1.0 + (exp(a) - 1.0) * i / 256.0);
col[i] = c;

If adjust < 0;
a= adjust**2/0.16;
b= 255.0 / log(a*255.0+1.0);
c= 256.0/a * log(1.0 + (exp(a) - 1.0) * (255-i) / 256.0);
col[i] = 255-c;

RETURN VALUE

0 - OK
2 - Bad pixtype
3 - Bad size
4 - Illegal value for adjust.

RESTRICTIONS

Works on unsigned byte bands only.

AUTHOR

Otto Milvang

This document was created byman2html,using the manual pages.