rt_util_rgb_to_hsv()

rt_errorstate rt_util_rgb_to_hsv	(	double	rgb[3],
		double	hsv[3]
	)

Definition at line 503 of file rt_util.c.

References DBL_EQ, ES_NONE, and s.

Referenced by test_rgb_to_hsv().

                                                 {
        int i;

        double minc;
        double maxc;

        double h = 0.;
        double s = 0.;
        double v = 0.;

        minc = rgb[0];
        maxc = rgb[0];

        /* get min and max values from RGB */
        for (i = 1; i < 3; i++) {
                if (rgb[i] > maxc)
                        maxc = rgb[i];
                if (rgb[i] < minc)
                        minc = rgb[i];
        }
        v = maxc;

        if (maxc != minc) {
                double diff = 0.;
                double rc = 0.;
                double gc = 0.;
                double bc = 0.;
                double junk = 0.;

                diff = maxc - minc;
                s = diff / maxc;
                rc = (maxc - rgb[0]) / diff;
                gc = (maxc - rgb[1]) / diff;
                bc = (maxc - rgb[2]) / diff;

                if (DBL_EQ(rgb[0], maxc))
                        h = bc - gc;
                else if (DBL_EQ(rgb[1], maxc))
                        h = 2.0 + rc - bc;
                else
                        h = 4.0 + gc - rc;

                h = modf((h / 6.0), &junk);
        }

        hsv[0] = h;
        hsv[1] = s;
        hsv[2] = v;

        return ES_NONE;
}

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