258 static bool tf_is_valid(const skcms_TransferFunction* tf) {  in tf_is_valid()  argument
260     if (!isfinitef_(tf->a + tf->b + tf->c + tf->d + tf->e + tf->f + tf->g)) {  in tf_is_valid()
265     if (tf->a < 0 || tf->c < 0 || tf->d < 0 || tf->g < 0) {  in tf_is_valid()
1411 float skcms_TransferFunction_eval(const skcms_TransferFunction* tf, float x) {  in skcms_TransferFunction_eval()  argument
1415     return sign * (x < tf->d ? tf->c * x + tf->f  in skcms_TransferFunction_eval()
1416                              : powf_(tf->a * x + tf->b, tf->g) + tf->e);  in skcms_TransferFunction_eval()
1523                           const skcms_TransferFunction* tf,  in rg_nonlinear()  argument
1529                 c = tf->c, d = tf->d, f = tf->f;  in rg_nonlinear()
1551                               const skcms_TransferFunction* tf,  in gauss_newton_step()  argument
1597         float resid = rg_nonlinear(x,curve,tf,P, dfdP);  in gauss_newton_step()
1632 static bool fit_nonlinear(const skcms_Curve* curve, int L, int N, skcms_TransferFunction* tf) {  in fit_nonlinear()  argument
1633     float P[3] = { tf->g, tf->a, tf->b };  in fit_nonlinear()
1645         if (P[1] * tf->d + P[2] < 0) {  in fit_nonlinear()
1646             P[2] = -P[1] * tf->d;  in fit_nonlinear()
1649                 P[1] * tf->d + P[2] >= 0);  in fit_nonlinear()
1651         if (!gauss_newton_step(curve, tf,  in fit_nonlinear()
1662     if (P[1] * tf->d + P[2] < 0) {  in fit_nonlinear()
1663         P[2] = -P[1] * tf->d;  in fit_nonlinear()
1666     tf->g = P[0];  in fit_nonlinear()
1667     tf->a = P[1];  in fit_nonlinear()
1668     tf->b = P[2];  in fit_nonlinear()
1669     tf->e =   tf->c*tf->d + tf->f  in fit_nonlinear()
1670       - powf_(tf->a*tf->d + tf->b, tf->g);  in fit_nonlinear()
1697         skcms_TransferFunction tf,  in skcms_ApproximateCurve()  local
1701         tf.f = 0.0f;  in skcms_ApproximateCurve()
1702         int L = fit_linear(curve, N, kTolerances[t], &tf.c, &tf.d);  in skcms_ApproximateCurve()
1707             tf.g = 1;  in skcms_ApproximateCurve()
1708             tf.a = tf.c;  in skcms_ApproximateCurve()
1709             tf.b = tf.f;  in skcms_ApproximateCurve()
1710             tf.c = tf.d = tf.e = tf.f = 0;  in skcms_ApproximateCurve()
1713             tf.g = 1;  in skcms_ApproximateCurve()
1714             tf.a = (eval_curve(curve, (N-1)*dx) -  in skcms_ApproximateCurve()
1717             tf.b = eval_curve(curve, (N-2)*dx)  in skcms_ApproximateCurve()
1718                  - tf.a * (N-2)*dx;  in skcms_ApproximateCurve()
1719             tf.e = 0;  in skcms_ApproximateCurve()
1725             tf.g = log2f_(mid_y) / log2f_(mid_x);  in skcms_ApproximateCurve()
1726             tf.a = 1;  in skcms_ApproximateCurve()
1727             tf.b = 0;  in skcms_ApproximateCurve()
1728             tf.e =    tf.c*tf.d + tf.f  in skcms_ApproximateCurve()
1729               - powf_(tf.a*tf.d + tf.b, tf.g);  in skcms_ApproximateCurve()
1732             if (!skcms_TransferFunction_invert(&tf, &tf_inv) ||  in skcms_ApproximateCurve()
1738             if (!skcms_TransferFunction_invert(&tf_inv, &tf)) {  in skcms_ApproximateCurve()
1750         if (!skcms_TransferFunction_invert(&tf, &tf_inv)) {  in skcms_ApproximateCurve()
1757             *approx    = tf;  in skcms_ApproximateCurve()
1984 static bool is_identity_tf(const skcms_TransferFunction* tf) {  in is_identity_tf()  argument
1985     return tf->g == 1 && tf->a == 1  in is_identity_tf()
1986         && tf->b == 0 && tf->c == 0 && tf->d == 0 && tf->e == 0 && tf->f == 0;  in is_identity_tf()
2337     skcms_TransferFunction tf[3];  in skcms_MakeUsableAsDestination()  local
2342             tf[i] = profile->trc[i].parametric;  in skcms_MakeUsableAsDestination()
2348         if (!skcms_ApproximateCurve(&profile->trc[i], &tf[i], &max_error)) {  in skcms_MakeUsableAsDestination()
2355         profile->trc[i].parametric = tf[i];  in skcms_MakeUsableAsDestination()