gamma.c File Reference

#include <math.h>
#include "round.h"

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Functions
int	gamma (int x, float gamma_value)

Function Documentation

int gamma	(	int	x,
		float	gamma_value
	)

Definition at line 24 of file gamma.c.

{
    static int gammamap[256];
    static float gv = 0.0;

    if (gv != gamma_value) {
        int i;

        gv = gamma_value;
        for (i = 0 ; i < 256 ; i++)
            gammamap[i] =
                round_positive(255.0 * pow( i/255.0, 1.0/gv));
    }

    return gammamap[x];
}