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+/**
+ * Copyright © 2016 Mattias Andrée <maandree@kth.se>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "libcolour.h"
+
+#include <errno.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+#define WASDIV0(x) (isinf(x) || isnan(x))
+
+
+
+static void to_rgb(const libcolour_colour_t* restrict from, libcolour_rgb_t* restrict to);
+static void to_srgb(const libcolour_colour_t* restrict from, libcolour_srgb_t* restrict to);
+static void to_ciexyy(const libcolour_colour_t* restrict from, libcolour_ciexyy_t* restrict to);
+static void to_ciexyz(const libcolour_colour_t* restrict from, libcolour_ciexyz_t* restrict to);
+static void to_cielab(const libcolour_colour_t* restrict from, libcolour_cielab_t* restrict to);
+static void to_cieluv(const libcolour_colour_t* restrict from, libcolour_cieluv_t* restrict to);
+static void to_cielchuv(const libcolour_colour_t* restrict from, libcolour_cielchuv_t* restrict to);
+static void to_yiq(const libcolour_colour_t* restrict from, libcolour_yiq_t* restrict to);
+static void to_ydbdr(const libcolour_colour_t* restrict from, libcolour_ydbdr_t* restrict to);
+static void to_yuv(const libcolour_colour_t* restrict from, libcolour_yuv_t* restrict to);
+static void to_ypbpr(const libcolour_colour_t* restrict from, libcolour_ypbpr_t* restrict to);
+static void to_ycgco(const libcolour_colour_t* restrict from, libcolour_ycgco_t* restrict to);
+static void to_cie1960ucs(const libcolour_colour_t* restrict from, libcolour_cie1960ucs_t* restrict to);
+static void to_cieuvw(const libcolour_colour_t* restrict from, libcolour_cieuvw_t* restrict to);
+
+
+static void ciexyz_to_rgb(const libcolour_ciexyz_t* restrict from, libcolour_rgb_t* restrict to)
+{
+ double X = from->X, Y = from->Y, Z = from->Z;
+ to->R = to->Minv[0][0] * X + to->Minv[0][1] * Y + to->Minv[0][2] * Z;
+ to->G = to->Minv[1][0] * X + to->Minv[1][1] * Y + to->Minv[1][2] * Z;
+ to->B = to->Minv[2][0] * X + to->Minv[2][1] * Y + to->Minv[2][2] * Z;
+}
+
+static void to_rgb(const libcolour_colour_t* restrict from, libcolour_rgb_t* restrict to)
+{
+ int have_gamma = 0, with_gamma = to->with_gamma;
+ libcolour_ciexyz_t tmp;
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYZ:
+ ciexyz_to_rgb(&from->ciexyz, to);
+ break;
+ case LIBCOLOUR_RGB:
+ if (!memcmp(from->rgb.M, to->M, sizeof(double[3][3]))) {
+ have_gamma = from->rgb.with_gamma;
+ *to = from->rgb;
+ break;
+ }
+ /* fall through */
+ default:
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp);
+ ciexyz_to_rgb(&tmp, to);
+ break;
+ }
+
+ if (have_gamma != with_gamma) {
+ if (with_gamma) {
+ switch (to->encoding_type) {
+ case LIBCOLOUR_ENCODING_TYPE_LINEAR:
+ break;
+ case LIBCOLOUR_ENCODING_TYPE_SIMPLE:
+ to->R = pow(to->R, 1 / to->gamma);
+ to->G = pow(to->G, 1 / to->gamma);
+ to->B = pow(to->B, 1 / to->gamma);
+ break;
+ case LIBCOLOUR_ENCODING_TYPE_REGULAR:
+ to->R <= to->transition ? to->slope * to->R : (1 + to->offset) * pow(to->R, 1 / to->gamma) - to->offset;
+ to->G <= to->transition ? to->slope * to->G : (1 + to->offset) * pow(to->G, 1 / to->gamma) - to->offset;
+ to->B <= to->transition ? to->slope * to->B : (1 + to->offset) * pow(to->B, 1 / to->gamma) - to->offset;
+ break;
+ case LIBCOLOUR_ENCODING_TYPE_CUSTOM:
+ to->R = (to->to_encoded_red)(to->R);
+ to->G = (to->to_encoded_green)(to->G);
+ to->B = (to->to_encoded_blue)(to->B);
+ break;
+ default:
+ fprintf(stderr, "libcolour: invalid encoding type\n");
+ abort();
+ }
+ } else {
+ switch (to->encoding_type) {
+ case LIBCOLOUR_ENCODING_TYPE_LINEAR:
+ break;
+ case LIBCOLOUR_ENCODING_TYPE_SIMPLE:
+ to->R = pow(to->R, to->gamma);
+ to->G = pow(to->G, to->gamma);
+ to->B = pow(to->B, to->gamma);
+ break;
+ case LIBCOLOUR_ENCODING_TYPE_REGULAR:
+ to->R <= to->transitioninv ? to->R * to->slope : pow((to->R + to->offset) / (1 + to->offset), to->gamma);
+ to->G <= to->transitioninv ? to->G * to->slope : pow((to->G + to->offset) / (1 + to->offset), to->gamma);
+ to->B <= to->transitioninv ? to->B * to->slope : pow((to->B + to->offset) / (1 + to->offset), to->gamma);
+ break;
+ case LIBCOLOUR_ENCODING_TYPE_CUSTOM:
+ to->R = (to->to_decoded_red)(to->R);
+ to->G = (to->to_decoded_green)(to->G);
+ to->B = (to->to_decoded_blue)(to->B);
+ break;
+ default:
+ fprintf(stderr, "libcolour: invalid encoding type\n");
+ abort();
+ }
+ }
+ }
+}
+
+
+static void ciexyz_to_srgb(const libcolour_ciexyz_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ double X = from->X, Y = from->Y, Z = from->Z;
+ to->R = 3.240450 * X + -1.537140 * Y + -0.4985320 * Z;
+ to->G = -0.969266 * X + 1.876010 * Y + 0.0415561 * Z;
+ to->B = 0.0556434 * X + -0.204026 * Y + 1.0572300 * Z;
+}
+
+static void srgb_to_srgb(const libcolour_srgb_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ if (from->with_gamma == to->with_gamma) {
+ *to = *from;
+ } else if (to->with_gamma) {
+ to->R = libcolour_srgb_encode(from->R);
+ to->G = libcolour_srgb_encode(from->G);
+ to->B = libcolour_srgb_encode(from->B);
+ } else {
+ to->R = libcolour_srgb_decode(from->R);
+ to->G = libcolour_srgb_decode(from->G);
+ to->B = libcolour_srgb_decode(from->B);
+ }
+}
+
+static void yiq_to_srgb(const libcolour_yiq_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ double Y = from->Y, I = from->I, Q = from->Q;
+ to->R = Y + I * 0.956 + Q * 0.621;
+ to->G = Y - I * 0.272 - Q * 0.647;
+ to->B = Y - I * 1.106 + Q * 1.703;
+}
+
+static void ydbdr_to_srgb(const libcolour_ydbdr_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ double Y = from->Y, Db = from->Db, Dr = from->Dr;
+ to->R = Y + Db * 0.000092303716148 - Dr * 0.525912630661865;
+ to->G = Y - Db * 0.129132898890509 + Dr * 0.267899328207599;
+ to->B = Y + Db * 0.664679059978955 - Dr * 0.000079202543533;
+}
+
+static void ypbpr_to_srgb(const libcolour_ypbpr_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ double Y = from->Y, Pb = from->Pb, Pr = from->Pr;
+ to->R = Pr + Y;
+ to->B = Pb + Y;
+ to->G = (Y - to->R * 0.2126 - to->B * 0.0722) / 0.7152;
+}
+
+static void ycgco_to_srgb(const libcolour_ycgco_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ double Y = from->Y, Cg = from->Cg, Co = from->Co;
+ to->R = Y - Cg + Co;
+ to->G = Y + Cg;
+ to->B = Y - Cg - Co;
+}
+
+static void other_to_srgb(const libcolour_colour_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ libcolour_ciexyz_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp);
+ ciexyz_to_srgb(&tmp, to);
+}
+
+static void to_srgb(const libcolour_colour_t* restrict from, libcolour_srgb_t* restrict to)
+{
+ libcolour_srgb_t tmp;
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYZ:
+ ciexyz_to_srgb(&from->ciexyz, to);
+ break;
+ case LIBCOLOUR_SRGB:
+ srgb_to_srgb(&from->srgb, to);
+ return;
+ case LIBCOLOUR_YIQ:
+ yiq_to_srgb(&from->yiq, to);
+ break;
+ case LIBCOLOUR_YDBDR:
+ ydbdr_to_srgb(&from->ydbdr, to);
+ break;
+ case LIBCOLOUR_YPBPR:
+ ypbpr_to_srgb(&from->ypbpr, to);
+ break;
+ case LIBCOLOUR_YCGCO:
+ ycgco_to_srgb(&from->ycgco, to);
+ break;
+ default:
+ other_to_srgb(from, to);
+ break;
+ }
+ if (to->with_gamma) {
+ tmp = *to;
+ tmp.with_gamma = 0;
+ srgb_to_srgb(&tmp, to);
+ }
+}
+
+
+static void ciexyz_to_ciexyy(const libcolour_ciexyz_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ double X = from->X, Y = from->Y, Z = from->Z;
+ double s = X + Y + Z;
+ to->x = X / s;
+ to->y = Y / s;
+ to->Y = Y;
+ if (WASDIV0(to->x) || WASDIV0(to->y))
+ to->x = to->y = 0;
+}
+
+static void other_to_ciexyy(const libcolour_colour_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ libcolour_ciexyz_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp);
+ ciexyz_to_ciexyy(&tmp, to);
+}
+
+static void srgb_to_ciexyy(const libcolour_srgb_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ libcolour_srgb_t tmp;
+ tmp.model = LIBCOLOUR_SRGB;
+ if (from->with_gamma) {
+ tmp.with_gamma = 0;
+ to_srgb((const libcolour_colour_t*)from, &tmp);
+ } else {
+ tmp = *from;
+ }
+ if (tmp.R == 0 && tmp.G == 0 && tmp.B == 0) {
+ to->x = 0.31272660439158;
+ to->y = 0.32902315240275;
+ to->Y = 0;
+ } else {
+ other_to_ciexyy((const libcolour_colour_t*)&tmp, to);
+ }
+}
+
+static void to_ciexyy(const libcolour_colour_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYY:
+ *to = from->ciexyy;
+ return;
+ case LIBCOLOUR_CIEXYZ:
+ ciexyz_to_ciexyy(&from->ciexyz, to);
+ return;
+ case LIBCOLOUR_SRGB:
+ srgb_to_ciexyy(&from->srgb, to);
+ return;
+ default:
+ other_to_ciexyy(from, to);
+ return;
+ }
+}
+
+
+static void rgb_to_ciexyz(const libcolour_rgb_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_rgb_t tmp;
+ double R, G, B;
+ if (from->with_gamma) {
+ tmp = *from;
+ tmp.with_gamma = 0;
+ to_rgb((const libcolour_colour_t*)from, &tmp);
+ R = tmp.R, G = tmp.G, B = tmp.B;
+ } else {
+ R = from->R, G = from->G, B = from->B;
+ }
+ to->X = from->M[0][0] * R + from->M[0][1] * G + from->M[0][2] * B;
+ to->Y = from->M[1][0] * R + from->M[1][1] * G + from->M[1][2] * B;
+ to->Z = from->M[2][0] * R + from->M[2][1] * G + from->M[2][2] * B;
+}
+
+static void srgb_to_ciexyz(const libcolour_srgb_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_srgb_t tmp;
+ double R, G, B;
+ if (from->with_gamma) {
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.with_gamma = 0;
+ to_srgb((const libcolour_colour_t*)from, &tmp);
+ R = tmp.R, G = tmp.G, B = tmp.B;
+ } else {
+ R = from->R, G = from->G, B = from->B;
+ }
+ to->X = 0.4124564 * R + 0.3575761 * G + 0.1804375 * B;
+ to->Y = 0.2126729 * R + 0.7151522 * G + 0.0721750 * B;
+ to->Z = 0.0193339 * R + 0.1191920 * G + 0.9503041 * B;
+}
+
+static void ciexyy_to_ciexyz(const libcolour_ciexyy_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ double x = from->x, y = from->y, Y = from->Y;
+ double Yy = Y / y;
+ if (WASDIV0(Yy)) {
+ to->X = to->Y = to->Z = Y;
+ } else {
+ to->X = x * Yy;
+ to->Y = Y;
+ to->Z = (1 - x - y) * Yy;
+ }
+}
+
+static inline double cielab_finv(double t)
+{
+ return (t > 6. / 29.) ? t * t * t : (t - 4. / 29.) * 108 / 841;
+}
+
+static void cielab_to_ciexyz(const libcolour_cielab_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ double L = from->L, a = from->a, b = from->b;
+ to->Y = (L + 16) / 116;
+ to->X = to->Y + a / 500;
+ to->Z = to->Y - b / 200;
+ to->X = cielab_finv(to->X) * 0.95047;
+ to->Y = cielab_finv(to->Y) * 1.08883;
+ to->Z = cielab_finv(to->Z);
+}
+
+static void cieluv_to_ciexyz(const libcolour_cieluv_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ double X = from->white.X, Y = from->white.Y, L = from->L, L13 = from->L * 13;
+ double t = X + 15 * Y + 3 * from->white.Z;
+ double u = from->u / L13 + 4 * X / t;
+ double v = from->v / L13 + 9 * Y / t;
+ if (L <= 8) {
+ Y *= L * 27 / 24389;
+ } else {
+ L = (L + 16) / 116;
+ Y *= L * L * L;
+ }
+ to->X = 2.25 * Y * u / v;
+ to->Y = Y;
+ to->Z = Y * (3 / v - 0.75 * u / v - 5);
+}
+
+static void cielchuv_to_ciexyz(const libcolour_cielchuv_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_cieluv_t tmp;
+ tmp.model = LIBCOLOUR_CIELUV;
+ tmp.white = from->white;
+ to_cieluv((const libcolour_colour_t*)from, &tmp);
+ cieluv_to_ciexyz(&tmp, to);
+}
+
+static void yuv_to_ciexyz(const libcolour_yuv_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_ydbdr_t tmp;
+ tmp.model = LIBCOLOUR_YDBDR;
+ to_ydbdr((const libcolour_colour_t*)from, &tmp);
+ to_ciexyz((const libcolour_colour_t*)&tmp, to);
+}
+
+static void cie1960ucs_to_ciexyz(const libcolour_cie1960ucs_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ double u = from->u, v = from->v, Y = from->Y;
+ to->X = 1.5 * Y * u / v;
+ to->Y = Y;
+ to->Z = (4 * Y - Y * u - 10 * Y * v) / (2 * v);
+}
+
+static void cieuvw_to_ciexyz(const libcolour_cieuvw_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_cie1960ucs_t tmp;
+ tmp.model = LIBCOLOUR_CIE1960UCS;
+ to_cie1960ucs((const libcolour_colour_t*)from, &tmp);
+ cie1960ucs_to_ciexyz(&tmp, to);
+}
+
+static void other_to_ciexyz(const libcolour_colour_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_srgb_t tmp;
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.with_gamma = 0;
+ to_srgb(from, &tmp);
+ srgb_to_ciexyz(&tmp, to);
+}
+
+static void to_ciexyz(const libcolour_colour_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_RGB:
+ rgb_to_ciexyz(&from->rgb, to);
+ return;
+ case LIBCOLOUR_SRGB:
+ srgb_to_ciexyz(&from->srgb, to);
+ return;
+ case LIBCOLOUR_CIEXYY:
+ ciexyy_to_ciexyz(&from->ciexyy, to);
+ return;
+ case LIBCOLOUR_CIEXYZ:
+ *to = from->ciexyz;
+ return;
+ case LIBCOLOUR_CIELAB:
+ cielab_to_ciexyz(&from->cielab, to);
+ return;
+ case LIBCOLOUR_CIELUV:
+ cieluv_to_ciexyz(&from->cieluv, to);
+ return;
+ case LIBCOLOUR_CIELCHUV:
+ cielchuv_to_ciexyz(&from->cielchuv, to);
+ return;
+ case LIBCOLOUR_YUV:
+ yuv_to_ciexyz(&from->yuv, to);
+ return;
+ case LIBCOLOUR_CIE1960UCS:
+ cie1960ucs_to_ciexyz(&from->cie1960ucs, to);
+ return;
+ case LIBCOLOUR_CIEUVW:
+ cieuvw_to_ciexyz(&from->cieuvw, to);
+ return;
+ default:
+ other_to_ciexyz(from, to);
+ return;
+ }
+}
+
+
+static inline double cielab_f(double t)
+{
+ return (t > 216. / 24389.) ? cbrt(t) : t * 841. / 108. + 4. / 29.;
+}
+
+static void ciexyz_to_cielab(const libcolour_ciexyz_t* restrict from, libcolour_cielab_t* restrict to)
+{
+ double X = from->X, Y = from->Y, Z = from->Z;
+ X /= 0.95047;
+ Y /= 1.08883;
+ Y = cielab_f(Y);
+ to->L = 116 * Y - 16;
+ to->a = 500 * (cielab_f(X) - Y);
+ to->b = 200 * (Y - cielab_f(Z));
+}
+
+static void other_to_cielab(const libcolour_colour_t* restrict from, libcolour_cielab_t* restrict to)
+{
+ libcolour_ciexyz_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp);
+ ciexyz_to_cielab(&tmp, to);
+}
+
+static void to_cielab(const libcolour_colour_t* restrict from, libcolour_cielab_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYZ:
+ ciexyz_to_cielab(&from->ciexyz, to);
+ return;
+ case LIBCOLOUR_CIELAB:
+ *to = from->cielab;
+ return;
+ default:
+ other_to_cielab(from, to);
+ return;
+ }
+}
+
+
+static void ciexyz_to_cieluv(const libcolour_ciexyz_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ double t, u, v, y, y2;
+ t = to->white.X + 15 * to->white.Y + 3 * to->white.Z;
+ u = 4 * to->white.X / t;
+ v = 9 * to->white.Y / t;
+ t = from->X + 15 * from->Y + 3 * from->Z;
+ u = 4 * from->X / t - u;
+ v = 9 * from->Y / t - v;
+ y = from->Y / to->white.Y;
+ y2 = y * 24389;
+ y = y2 <= 216 ? y2 / 27 : cbrt(y) * 116 - 16;
+ to->L = y;
+ y *= 13;
+ to->u = u * y;
+ to->v = v * y;
+}
+
+static void cielchuv_to_cieluv(const libcolour_cielchuv_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ libcolour_ciexyz_t tmp;
+ libcolour_cielchuv_t tmp2;
+ double L, C, h;
+ if (to->white.X != from->white.X || to->white.Y != from->white.Y || to->white.Z != from->white.Z) {
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ tmp2.model = LIBCOLOUR_CIELCHUV;
+ tmp2.white = to->white;
+ to_ciexyz((const libcolour_colour_t*)from, &tmp);
+ to_cielchuv((const libcolour_colour_t*)&tmp, &tmp2);
+ L = tmp2.L, C = tmp2.C, h = tmp2.h;
+ } else {
+ L = from->L, C = from->C, h = from->h;
+ }
+ to->L = L;
+ to->u = C * cos(h);
+ to->v = C * sin(h);
+}
+
+static void other_to_cieluv(const libcolour_colour_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ libcolour_ciexyz_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp);
+ ciexyz_to_cieluv(&tmp, to);
+}
+
+static void to_cieluv(const libcolour_colour_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYZ:
+ ciexyz_to_cieluv(&from->ciexyz, to);
+ return;
+ case LIBCOLOUR_CIELCHUV:
+ cielchuv_to_cieluv(&from->cielchuv, to);
+ return;
+ case LIBCOLOUR_CIELUV:
+ if (to->white.X == from->cieluv.white.X &&
+ to->white.Y == from->cieluv.white.Y &&
+ to->white.Z == from->cieluv.white.Z) {
+ *to = from->cieluv;
+ return;
+ }
+ /* fall through */
+ default:
+ other_to_cieluv(from, to);
+ return;
+ }
+}
+
+
+static void cieluv_to_cielchuv(const libcolour_cieluv_t* restrict from, libcolour_cielchuv_t* restrict to)
+{
+ libcolour_cieluv_t tmp;
+ double L, u, v;
+ if (to->white.X != from->white.X || to->white.Y != from->white.Y || to->white.Z != from->white.Z) {
+ tmp.model = LIBCOLOUR_CIELUV;
+ tmp.white = to->white;
+ to_cieluv((const libcolour_colour_t*)from, &tmp);
+ L = tmp.L, u = tmp.u, v = tmp.v;
+ } else {
+ L = from->L, u = from->u, v = from->v;
+ }
+ to->L = L;
+ to->C = sqrt(u * u + v * v);
+ to->h = atan2(v, u);
+}
+
+static void other_to_cielchuv(const libcolour_colour_t* restrict from, libcolour_cielchuv_t* restrict to)
+{
+ libcolour_cieluv_t tmp;
+ tmp.model = LIBCOLOUR_CIELUV;
+ tmp.white = to->white;
+ to_cieluv(from, &tmp);
+ cieluv_to_cielchuv(&tmp, to);
+}
+
+static void to_cielchuv(const libcolour_colour_t* restrict from, libcolour_cielchuv_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIELUV:
+ cieluv_to_cielchuv(&from->cieluv, to);
+ return;
+ case LIBCOLOUR_CIELCHUV:
+ if (to->white.X == from->cielchuv.white.X &&
+ to->white.Y == from->cielchuv.white.Y &&
+ to->white.Z == from->cielchuv.white.Z) {
+ *to = from->cielchuv;
+ return;
+ }
+ /* fall through */
+ default:
+ other_to_cielchuv(from, to);
+ return;
+ }
+}
+
+
+static void to_yiq(const libcolour_colour_t* restrict from, libcolour_yiq_t* restrict to)
+{
+ /* TODO to_yiq: add direct conversion from and to CIE XYZ and use it as the default intermediary */
+ double r, g, b;
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YIQ:
+ *to = from->yiq;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_SRGB:
+ if (tmp.srgb.with_gamma) {
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ }
+ r = tmp.srgb.R;
+ g = tmp.srgb.G;
+ b = tmp.srgb.B;
+ to->Y = r * 0.29893602129377540 + g * 0.5870430744511212 + b * 0.11402090425510336;
+ to->I = r * 0.59594574307079930 - g * 0.2743886357457892 - b * 0.32155710732501010;
+ to->Q = r * 0.21149734030682846 - g * 0.5229106903029739 + b * 0.31141334999614540;
+ return;
+ }
+}
+
+
+static void to_ydbdr(const libcolour_colour_t* restrict from, libcolour_ydbdr_t* restrict to)
+{
+ /* TODO to_ydbdr: add direct conversion from and to CIE XYZ and use it as the default intermediary */
+ double r, g, b;
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YDBDR:
+ *to = from->ydbdr;
+ return;
+ case LIBCOLOUR_YUV:
+ to->Y = tmp.yuv.Y;
+ to->Db = tmp.yuv.U * 3.069;
+ to->Dr = -tmp.yuv.V * 2.169;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_SRGB:
+ if (tmp.srgb.with_gamma) {
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ }
+ r = tmp.srgb.R;
+ g = tmp.srgb.G;
+ b = tmp.srgb.B;
+ to->Y = r * 0.299 + g * 0.587 + b * 0.114;
+ to->Db = -r * 0.450 - g * 0.883 + b * 1.333;
+ to->Dr = -r * 1.333 + g * 1.116 + b * 0.217;
+ return;
+ }
+}
+
+
+static void to_yuv(const libcolour_colour_t* restrict from, libcolour_yuv_t* restrict to)
+{
+ /* TODO to_yuv: add direct conversion from and to CIE XYZ and use it as the default intermediary */
+ /* TODO to_yub: add direct conversion from and to sRGB */
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YUV:
+ *to = from->yuv;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_YDBDR;
+ to_ydbdr(from, &tmp.ydbdr);
+ /* fall through */
+ case LIBCOLOUR_YDBDR:
+ to->Y = tmp.ydbdr.Y;
+ to->U = tmp.ydbdr.Db / 3.069;
+ to->V = -tmp.ydbdr.Dr / 2.169;
+ return;
+ }
+}
+
+
+static void to_ypbpr(const libcolour_colour_t* restrict from, libcolour_ypbpr_t* restrict to)
+{
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YPBPR:
+ *to = from->ypbpr;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_SRGB:
+ if (tmp.srgb.with_gamma) {
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ }
+ to->Y = tmp.srgb.R * 0.2126 + tmp.srgb.G * 0.7152 + tmp.srgb.B * 0.0722;
+ to->Pb = tmp.srgb.B - to->Y;
+ to->Pr = tmp.srgb.R - to->Y;
+ return;
+ }
+}
+
+
+static void to_ycgco(const libcolour_colour_t* restrict from, libcolour_ycgco_t* restrict to)
+{
+ /* TODO to_ycgco: add direct conversion from and to CIE XYZ and use it as the default intermediary */
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YCGCO:
+ *to = from->ycgco;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_SRGB:
+ if (tmp.srgb.with_gamma) {
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ }
+ to->Y = tmp.srgb.R / 4 + tmp.srgb.G / 2 + tmp.srgb.B / 4;
+ to->Cg = -tmp.srgb.R / 4 + tmp.srgb.G / 2 - tmp.srgb.B / 4;
+ to->Co = tmp.srgb.R / 2 - tmp.srgb.B / 2;
+ return;
+ }
+}
+
+
+static void to_cie1960ucs(const libcolour_colour_t* restrict from, libcolour_cie1960ucs_t* restrict to)
+{
+ libcolour_colour_t tmp = *from;
+ double u, v, w, y;
+ switch (from->model) {
+ case LIBCOLOUR_CIE1960UCS:
+ *to = from->cie1960ucs;
+ return;
+ case LIBCOLOUR_CIEUVW:
+ u = from->cieuvw.U, v = from->cieuvw.V, w = from->cieuvw.W;
+ y = (w + 17) / 25;
+ y *= y * y;
+ w *= 13;
+ to->u = u / w + from->cieuvw.u0;
+ to->v = v / w + from->cieuvw.v0;
+ to->Y = y;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp.ciexyz);
+ /* fall through */
+ case LIBCOLOUR_CIEXYZ:
+ w = tmp.ciexyz.X + 15 * tmp.ciexyz.Y + 3 * tmp.ciexyz.Z;
+ to->u = 4 * tmp.ciexyz.X / w;
+ to->v = 6 * tmp.ciexyz.Y / w;
+ to->Y = tmp.ciexyz.Y;
+ return;
+ }
+}
+
+
+static void to_cieuvw(const libcolour_colour_t* restrict from, libcolour_cieuvw_t* restrict to)
+{
+ double U, V, W, w;
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_CIEUVW:
+ U = from->cieuvw.U, V = from->cieuvw.V, W = from->cieuvw.W;
+ w = W * 13;
+ U += w * (from->cieuvw.u0 - to->u0);
+ V += w * (from->cieuvw.v0 - to->v0);
+ to->U = U, to->V = V, to->W = W;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_CIE1960UCS;
+ to_cie1960ucs(from, &tmp.cie1960ucs);
+ /* fall through */
+ case LIBCOLOUR_CIE1960UCS:
+ U = tmp.cie1960ucs.u, V = tmp.cie1960ucs.v, W = tmp.cie1960ucs.Y;
+ W = 25 * cbrt(W) - 17;
+ w = W * 13;
+ to->U = w * (U - to->u0);
+ to->V = w * (V - to->v0);
+ to->W = W;
+ return;
+ }
+}
+
+
+
+int libcolour_convert(const libcolour_colour_t* restrict from, libcolour_colour_t* restrict to)
+{
+#define X(C, T) 1 +
+ if (from->model < 0 || from->model > LIBCOLOUR_LIST_MODELS 0) {
+#undef X
+ errno = EINVAL;
+ return -1;
+ }
+ switch (to->model) {
+ case LIBCOLOUR_RGB:
+ to_rgb(from, &to->rgb);
+ break;
+ case LIBCOLOUR_SRGB:
+ to_srgb(from, &to->srgb);
+ break;
+ case LIBCOLOUR_CIEXYY:
+ to_ciexyy(from, &to->ciexyy);
+ break;
+ case LIBCOLOUR_CIEXYZ:
+ to_ciexyz(from, &to->ciexyz);
+ break;
+ case LIBCOLOUR_CIELAB:
+ to_cielab(from, &to->cielab);
+ break;
+ case LIBCOLOUR_CIELUV:
+ to_cieluv(from, &to->cieluv);
+ break;
+ case LIBCOLOUR_CIELCHUV:
+ to_cielchuv(from, &to->cielchuv);
+ break;
+ case LIBCOLOUR_YIQ:
+ to_yiq(from, &to->yiq);
+ break;
+ case LIBCOLOUR_YDBDR:
+ to_ydbdr(from, &to->ydbdr);
+ break;
+ case LIBCOLOUR_YUV:
+ to_yuv(from, &to->yuv);
+ break;
+ case LIBCOLOUR_YPBPR:
+ to_ypbpr(from, &to->ypbpr);
+ break;
+ case LIBCOLOUR_YCGCO:
+ to_ycgco(from, &to->ycgco);
+ break;
+ case LIBCOLOUR_CIE1960UCS:
+ to_cie1960ucs(from, &to->cie1960ucs);
+ break;
+ case LIBCOLOUR_CIEUVW:
+ to_cieuvw(from, &to->cieuvw);
+ break;
+ default:
+ errno = EINVAL;
+ return -1;
+ }
+ return 0;
+}
+
generated by cgit v1.2.3-70-g09d2 (git 2.47.0) at 2024-11-17 12:37:35 +0000