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-rw-r--r--src/libcolour.c952
-rw-r--r--src/libcolour.h196
2 files changed, 1148 insertions, 0 deletions
diff --git a/src/libcolour.c b/src/libcolour.c
new file mode 100644
index 0000000..e613280
--- /dev/null
+++ b/src/libcolour.c
@@ -0,0 +1,952 @@
+/**
+ * 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 <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_cielch(const libcolour_colour_t* restrict from, libcolour_cielch_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_colour_t tmp;
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYZ:
+ ciexyz_to_rgb(&from->ciexyz, to);
+ break;
+ case LIBCOLOUR_RGB:
+ if (!memcmp(from->M, to->M, sizeof(double[3][3]))) {
+ have_gamma = from->with_gamma;
+ *to = *from;
+ break;
+ }
+ /* fall through */
+ default:
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp.ciexyz);
+ ciexyz_to_rgb(&tmp.ciexyz, to);
+ break;
+ }
+ if (have_gamma != with_gamma) {
+ if (with_gamma) {
+ to->R = to->regular_gamma ? pow(to->R, 1 / to->gamma) : (to->to_encoded_red)(to->R);
+ to->G = to->regular_gamma ? pow(to->G, 1 / to->gamma) : (to->to_encoded_green)(to->G);
+ to->B = to->regular_gamma ? pow(to->B, 1 / to->gamma) : (to->to_encoded_blue)(to->B);
+ } else {
+ to->R = to->regular_gamma ? pow(to->R, to->gamma) : (to->to_decoded_red)(to->R);
+ to->G = to->regular_gamma ? pow(to->G, to->gamma) : (to->to_decoded_green)(to->G);
+ to->B = to->regular_gamma ? pow(to->B, to->gamma) : (to->to_decoded_blue)(to->B);
+ }
+ }
+}
+
+
+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) {
+ from->R = libcolour_srgb_encode(to->R);
+ from->G = libcolour_srgb_encode(to->G);
+ from->B = libcolour_srgb_encode(to->B);
+ } else {
+ from->R = libcolour_srgb_decode(to->R);
+ from->G = libcolour_srgb_decode(to->G);
+ from->B = libcolour_srgb_decode(to->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_colour_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp.ciexyz);
+ ciexyz_to_srgb(&tmp.ciexyz, 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 srgb_to_ciexyy(const libcolour_srgb_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ tmp.model = LIBCOLOUR_SRGB;
+ if (from->with_gamma) {
+ tmp.srgb.with_gamma = 0;
+ to_srgb((const libcolour_colour_t *)from, &tmp.srgb);
+ } else {
+ tmp.srgb = *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(&tmp, to);
+ }
+}
+
+static void other_to_ciexyy(const libcolour_colour_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp.ciexyz);
+ ciexyz_to_ciexyy(&tmp.ciexyz, to);
+}
+
+static void to_ciexyy(const libcolour_colour_t* restrict from, libcolour_ciexyy_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIEXYY:
+ *to = *from;
+ 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_colour_t tmp;
+ double R, G, B;
+ if (from->with_gamma) {
+ tmp = *from;
+ tmp.rgb.with_gamma = 0;
+ to_rgb(from, &tmp);
+ R = tmp.R, G = tmp.G, B = tmp.B;
+ } else {
+ R = from->R, G = from->G, B = from->B;
+ }
+ to->X = to->M[0][0] * R + to->M[0][1] * G + to->M[0][2] * B;
+ to->Y = to->M[1][0] * R + to->M[1][1] * G + to->M[1][2] * B;
+ to->Z = to->M[2][0] * R + to->M[2][1] * G + to->M[2][2] * B;
+}
+
+static void srgb_to_ciexyz(const libcolour_srgb_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ double R, G, B;
+ if (from->with_gamma) {
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.srgb.with_gamma = 0;
+ to_srgb(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 x)
+{
+ double x3 = x * x * x;
+ return (x3 > 0.00885642) ? x3 : (x - 0.1379310) / (7.78 + 703 / 99900);
+}
+
+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 / 300;
+ to->X = cielab_finv(to->X) * 0.95047;
+ to->Y = cielab_finv(to->Y);
+ to->Z = cielab_finv(to->Z) * 1.08883;
+}
+
+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 cielch_to_ciexyz(const libcolour_cielch_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ tmp.model = LIBCOLOUR_YUV;
+ tmp.yuv.white = from.white;
+ to_yuv((const libcolour_colour_t*)from, &tmp.yuv);
+ yuv_to_ciexyz(&tmp.yuv, to);
+}
+
+static void yuv_to_ciexyz(const libcolour_yuv_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ tmp.model = LIBCOLOUR_YDBDR;
+ to_ydbdr((const libcolour_colour_t*)from, &tmp.ydbdr);
+ ydbdr_to_ciexyz(&tmp.ydbdr, 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_colour_t tmp;
+ tmp.model = LIBCOLOUR_CIE1969UCS;
+ to_cie1960ucs((const libcolour_cieuvw_t*)from, &tmp.cie1960ucs);
+ cie1960ucs_to_ciexyz(&tmp.cie1960ucs, to);
+}
+
+static void other_to_ciexyz(const libcolour_colour_t* restrict from, libcolour_ciexyz_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ tmp.model = LIBCOLOUR_SRGB;
+ tmp.srgb.with_gamma = 0;
+ to_srgb(from, &tmp.srgb);
+ srgb_to_ciexyz(&tmp.srgb, 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
+ return;
+ case LIBCOLOUR_CIELAB:
+ cielab_to_ciexyz(&from->cielab, to);
+ return;
+ case LIBCOLOUR_CIELUV:
+ cieluv_to_ciexyz(&from->cieluv, to);
+ return;
+ case LIBCOLOUR_CIELCH:
+ cielch_to_ciexyz(&from->cielch, 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 x)
+{
+ return (x > 0.00885642) ? cbrt(x) : x * (7.78 + 703 / 99900) + 0.1379310;
+}
+
+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_colour_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp.ciexyz);
+ ciexyz_to_cielab(&tmp.ciexyz, 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;
+ return;
+ default:
+ other_to_cielab(from, to);
+ return;
+ }
+}
+
+
+static void ciexyz_to_cieluv(const libcolour_ciexyz_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ libcolour_ciexyz_t white;
+ double t, u, v, y, y2;
+ if (to->white.model == LIBCOLOUR_CIEXYZ) {
+ white = to->white.ciexyz;
+ } else {
+ white.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(&to->white, &white);
+ }
+ t = white.X + 15 * white.Y + 3 * white.Z;
+ u = 4 * white.x / t;
+ v = 9 * white.y / t;
+ t = from->X + 15 * from->Y + 4 * from->Z;
+ u = 4 * from->x / t - u;
+ v = 9 * from->y / t - v;
+ y = from->Y = 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 cielch_to_cieluv(const libcolour_cielch_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ libcolour_ciexyz_t from_white, to_white;
+ libcolour_colour_t tmp, tmp2;
+ double L, C, h;
+ if (from->white.model == LIBCOLOUR_CIEXYZ) {
+ from_white = from->white.ciexyz;
+ } else {
+ from_white.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(&from->white, &from_white);
+ }
+ if (to->white.model == LIBCOLOUR_CIEXYZ) {
+ to_white = to->white.ciexyz;
+ } else {
+ to_white.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(&to->white, &to_white);
+ }
+ 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_CIELCH;
+ tmp2.cielch.white.ciexyz = to_white;
+ to_ciexyz(from, &tmp.ciexyz);
+ to_cielch(&tmp, &tmp2.cielch);
+ L = tmp2.cielch.L, C = tmp2.cielch.C, h = tmp2.cielch.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_colour_t tmp;
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(from, &tmp.ciexyz);
+ ciexyz_to_cieluv(&tmp.ciexyz, to);
+}
+
+static void to_cieluv(const libcolour_colour_t* restrict from, libcolour_cieluv_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIELCH:
+ cielch_to_cielab(&from->cielch, to);
+ return;
+ case LIBCOLOUR_CIELUV:
+ if (to->cieluv.model == LIBCOLOUR_CIEXYZ &&
+ from->cieluv.model == LIBCOLOUR_CIEXYZ &&
+ to->cieluv.white.X == from->cieluv.white.X &&
+ to->cieluv.white.Y == from->cieluv.white.Y &&
+ to->cieluv.white.Z == from->cieluv.white.Z) {
+ *to = *from;
+ return;
+ }
+ /* fall through */
+ default:
+ other_to_cieluv(from, to);
+ return;
+ }
+}
+
+
+static void cieluv_to_cielch(const libcolour_cieluv_t* restrict from, libcolour_cielch_t* restrict to)
+{
+ libcolour_ciexyz_t from_white, to_white;
+ libcolour_cieluv_t tmp;
+ double L, u, v;
+ if (from->white.model == LIBCOLOUR_CIEXYZ) {
+ from_white = from->white.ciexyz;
+ } else {
+ from_white.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(&from->white, &from_white);
+ }
+ if (to->white.model == LIBCOLOUR_CIEXYZ) {
+ to_white = to->white.ciexyz;
+ } else {
+ to_white.model = LIBCOLOUR_CIEXYZ;
+ to_ciexyz(&to->white, &to_white);
+ }
+ 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.ciexyz = to_white;
+ to_cieluv(from, &tmp);
+ L = tmp.L, u = tmp.u, v = tmp.v;
+ } else {
+ L = from->L, u = from->u, v = from->u;
+ }
+ to->L = L;
+ to->C = sqrt(u * u + v * v);
+ to->h = atan2(v, u);
+}
+
+static void other_to_cielch(const libcolour_colour_t* restrict from, libcolour_cielch_t* restrict to)
+{
+ libcolour_colour_t tmp;
+ tmp.model = LIBCOLOUR_CIELUV;
+ tmp.white = to.white;
+ to_cieluv(from, &tmp.cieluv);
+ cieluv_to_cielch(&tmp.cieluv, to);
+}
+
+static void to_cielch(const libcolour_colour_t* restrict from, libcolour_cielch_t* restrict to)
+{
+ switch (from->model) {
+ case LIBCOLOUR_CIELUV:
+ cieluv_to_cielch(&from->cieluv, to);
+ return;
+ case LIBCOLOUR_CIELCH:
+ if (to->cielch.model == LIBCOLOUR_CIEXYZ &&
+ from->cielch.model == LIBCOLOUR_CIEXYZ &&
+ to->cielch.white.X == from->cielcg.white.X &&
+ to->cielch.white.Y == from->cielch.white.Y &&
+ to->cielch.white.Z == from->cielch.white.Z) {
+ *to = *from;
+ return;
+ }
+ /* fall through */
+ default:
+ other_to_cielch(from, to);
+ return;
+ }
+}
+
+
+static void to_yiq(const libcolour_colour_t* restrict from, libcolour_yiq_t* restrict to)
+{
+ double r, g, b;
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YIQ:
+ *to = *from;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_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)
+{
+ double r, g, b;
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YDBDR:
+ *to = *from;
+ 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;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_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)
+{
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YUV:
+ *to = *from;
+ 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;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_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)
+{
+ libcolour_colour_t tmp = *from;
+ switch (from->model) {
+ case LIBCOLOUR_YCGCO:
+ *to = *from;
+ return;
+ default:
+ tmp.model = LIBCOLOUR_SRGB;
+ to_srgb(from, &tmp.srgb);
+ /* fall through */
+ case LIBCOLOUR_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;
+ 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 = from->cie1960ucs.u, V = from->cie1960ucs.v, W = from->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)
+{
+ if (from->model < 0 || from->model > LIBCOLOUR_CIEUVW) {
+ 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_CIELCH:
+ to_cielch(from, &to->cielch);
+ 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;
+}
+
+
+double libcolour_srgb_encode(double x)
+{
+ return x <= 0.0031308 ? 12.92 * x : 1.055 * pow(x, 1 / 2.4) - 0.055;
+}
+
+double libcolour_srgb_decode(double x)
+{
+ return x <= 0.04045 ? x / 12.92 : pow((x + 0.055) / 1.055, 2.4);
+}
+
+
+int libcolour_delta_e(const libcolour_colour_t* a, const libcolour_colour_t* b, double* e)
+{
+ libcolour_colour_t u, v;
+ u.model = v.model = LIBCOLOUR_CIELAB;
+ if (libcolour_convert(a, &u))
+ return -1;
+ if (libcolour_convert(b, &v))
+ return -1;
+ u.L -= v.L, u.L *= u.L;
+ u.a -= v.a, u.a *= u.a;
+ u.b -= v.b, u.b *= u.b;
+ *e = sqrt(u.L + u.a + u.b);
+ return 0;
+}
+
+
+static int eliminate(double** M, size_t n, size_t m)
+{
+ size_t r1, r2, c;
+ double d;
+ double* R1;
+ double* R2;
+ for (r1 = 0; r1 < n; r1++) {
+ R1 = M[r1];
+ if (R1[r1] == 0) {
+ for (r2 = r1 + 1; r2 < n; r2++)
+ if (M[r2][r1] != 0)
+ break;
+ if (r2 == n) {
+ errno = EDOM;
+ return -1;
+ }
+ R2 = M[r2];
+ for (c = 0; c < m; c++)
+ d = R1[c], R1[c] = R2[c], R2[c] = d;
+ }
+ d = R1[r1];
+ for (c = 0; c < m; c++)
+ R1[c] /= d;
+ for (r2 = r1 + 1; r2 < n; r2++) {
+ R2 = M[r2];
+ d = R2[r1];
+ for (c = 0; c < m; c++)
+ R2[c] -= R1[c] * d;
+ }
+ }
+ for (r1 = n; --r1;) {
+ R1 = M[r1];
+ for (r2 = r1; --r2;) {
+ R2 = M[r2];
+ d = R2[r1];
+ for (c = 0; c < m; c++)
+ R2[c] -= R1[c] * d;
+ }
+ }
+ return 0;
+}
+
+
+int libcolour_proper(libcolour_colour_t* colour)
+{
+ libcolour_colour_t tmp, r, g, b;
+ double m[3][4]
+ switch (colour->model) {
+ case LIBCOLOUR_RGB:
+ if (colour->rgb.red.model != LIBCOLOUR_CIEXYY) {
+ tmp.model = LIBCOLOUR_CIEXYY;
+ libcolour_convert(&colour->rgb.red, &tmp);
+ colour->rgb.red = tmp;
+ }
+ if (colour->rgb.green.model != LIBCOLOUR_CIEXYY) {
+ tmp.model = LIBCOLOUR_CIEXYY;
+ libcolour_convert(&colour->rgb.green, &tmp);
+ colour->rgb.green = tmp;
+ }
+ if (colour->rgb.blue.model != LIBCOLOUR_CIEXYY) {
+ tmp.model = LIBCOLOUR_CIEXYY;
+ libcolour_convert(&colour->rgb.blue, &tmp);
+ colour->rgb.blue = tmp;
+ }
+ if (colour->rgb.white.model != LIBCOLOUR_CIEXYY) {
+ tmp.model = LIBCOLOUR_CIEXYY;
+ libcolour_convert(&colour->rgb.white, &tmp);
+ colour->rgb.white = tmp;
+ }
+ colour->rgb.red.ciexyy.Y = 1;
+ colour->rgb.green.ciexyy.Y = 1;
+ colour->rgb.blue.ciexyy.Y = 1;
+ r.model = g.model = b.model = tmp.model = LIBCOLOUR_CIEXYZ;
+ libcolour_convert(&colour->rgb.red, &r);
+ libcolour_convert(&colour->rgb.green, &g);
+ libcolour_convert(&colour->rgb.blue, &b);
+ libcolour_convert(&colour->rgb.white, &tmp);
+ m[0][0] = r.ciexyz.X, m[0][1] = g.ciexyz.X, m[0][2] = b.ciexyz.X, m[0][3] = tmp.ciexyz.X;
+ m[1][0] = r.ciexyz.Y, m[1][1] = g.ciexyz.Y, m[1][2] = b.ciexyz.Y, m[1][3] = tmp.ciexyz.Y;
+ m[2][0] = r.ciexyz.Z, m[2][1] = g.ciexyz.Z, m[2][2] = b.ciexyz.Z, m[2][3] = tmp.ciexyz.Z;
+ if (eliminate(m, 3, 4))
+ return -1;
+ colour->rgb.red.ciexyy.Y = m[0][3];
+ colour->rgb.green.ciexyy.Y = m[1][3];
+ colour->rgb.blue.ciexyy.Y = m[2][3];
+ break;
+ case LIBCOLOUR_CIELUV:
+ if (colour->cieluv.white.model != LIBCOLOUR_CIEXYZ) {
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ libcolour_convert(&colour->cieluv.white, &tmp);
+ colour->cieluv.white = tmp;
+ }
+ break;
+ case LIBCOLOUR_CIELCH:
+ if (colour->cielch.white.model != LIBCOLOUR_CIEXYZ) {
+ tmp.model = LIBCOLOUR_CIEXYZ;
+ libcolour_convert(&colour->cielch.white, &tmp);
+ colour->cielch.white = tmp;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
diff --git a/src/libcolour.h b/src/libcolour.h
new file mode 100644
index 0000000..f579dfb
--- /dev/null
+++ b/src/libcolour.h
@@ -0,0 +1,196 @@
+/**
+ * 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/>.
+ */
+#ifndef LIBCOLOUR_H
+#define LIBCOLOUR_H
+
+
+
+union libcolour_colour;
+
+
+typedef enum libcolour_model {
+ LIBCOLOUR_RGB,
+ LIBCOLOUR_SRGB,
+ LIBCOLOUR_CIEXYY,
+ LIBCOLOUR_CIEXYZ,
+ LIBCOLOUR_CIELAB,
+ LIBCOLOUR_CIELUV,
+ LIBCOLOUR_CIELCH,
+ LIBCOLOUR_YIQ,
+ LIBCOLOUR_YDBDR,
+ LIBCOLOUR_YUV,
+ LIBCOLOUR_YPBPR,
+ LIBCOLOUR_YCGCO,
+ LIBCOLOUR_CIE1960UCS,
+ LIBCOLOUR_CIEUVW
+} libcolour_model_t;
+
+
+typedef enum libcolour_rgb_colour_space {
+} libcolour_rgb_colour_space_t;
+
+
+typedef struct libcolour_rgb {
+ enum libcolour_model model;
+ double R;
+ double G;
+ double B;
+ int with_gamma;
+ int regular_gamma;
+ double gamma;
+ union libcolour_colour red;
+ union libcolour_colour green;
+ union libcolour_colour blue;
+ union libcolour_colour white;
+ double (*to_encoded_red)(double);
+ double (*to_decoded_red)(double);
+ double (*to_encoded_green)(double);
+ double (*to_decoded_green)(double);
+ double (*to_encoded_blue)(double);
+ double (*to_decoded_blue)(double);
+ double M[3][3];
+ double Minv[3][3];
+ enum libcolour_rgb_colour_space colour_space;
+} libcolour_srgb_t;
+
+typedef struct libcolour_srgb {
+ enum libcolour_model model;
+ double R;
+ double G;
+ double B;
+ int with_gamma;
+} libcolour_srgb_t;
+
+typedef struct libcolour_ciexyy {
+ enum libcolour_model model;
+ double x;
+ double y;
+ double Y;
+} libcolour_ciexyy_t;
+
+typedef struct libcolour_ciexyz {
+ enum libcolour_model model;
+ double X;
+ double Y;
+ double Z;
+} libcolour_ciexyz_t;
+
+typedef struct libcolour_cielab {
+ enum libcolour_model model;
+ double L;
+ double a;
+ double n;
+} libcolour_cielab_t;
+
+typedef struct libcolour_cieluv {
+ enum libcolour_model model;
+ double L;
+ double u;
+ double v;
+ union libcolour_colour white;
+} libcolour_cieluv_t;
+
+typedef struct libcolour_cielch {
+ enum libcolour_model model;
+ double L;
+ double C;
+ double h;
+ union libcolour_colour white;
+} libcolour_cielch_t;
+
+typedef struct libcolour_yiq {
+ enum libcolour_model model;
+ double Y;
+ double I;
+ double Q;
+} libcolour_yiq_t;
+
+typedef struct libcolour_ydbdr {
+ enum libcolour_model model;
+ double Y;
+ double Db;
+ double Dr;
+} libcolour_ydbdr_t;
+
+typedef struct libcolour_yuv {
+ enum libcolour_model model;
+ double Y;
+ double U;
+ double V;
+} libcolour_yuv_t;
+
+typedef struct libcolour_ypbpr {
+ enum libcolour_model model;
+ double Y;
+ double Pb;
+ double Pr;
+} libcolour_ypbpr_t;
+
+typedef struct libcolour_ycgco {
+ enum libcolour_model model;
+ double Y;
+ double Cg;
+ double Co;
+} libcolour_ycgco_t;
+
+typedef struct libcolour_cie1960ucs {
+ enum libcolour_model model;
+ double u;
+ double v;
+ double Y;
+} libcolour_cie1960ucs_t;
+
+typedef struct libcolour_cieuvw {
+ enum libcolour_model model;
+ double U;
+ double V;
+ double W;
+ double u0;
+ double v0;
+} libcolour_cieuvw_t;
+
+
+typedef union libcolour_colour {
+ enum libcolour_model model;
+ struct libcolour_rgb rgb;
+ struct libcolour_srgb srgb;
+ struct libcolour_ciexyy ciexyy;
+ struct libcolour_ciexyz ciexyz;
+ struct libcolour_cielab cielab;
+ struct libcolour_cieluv cieluv;
+ struct libcolour_cielch cielch;
+ struct libcolour_yiq yiq;
+ struct libcolour_ydbdr ydbdr;
+ struct libcolour_yuv yuv;
+ struct libcolour_ypbpr ypbpr;
+ struct libcolour_ycgco ycgco;
+ struct libcolour_cie1960ucs cie1960ucs;
+ struct libcolour_cieuvw cieuvw;
+} libcolour_colour_t;
+
+
+
+int libcolour_convert(const libcolour_colour_t* restrict from, libcolour_colour_t* restrict to);
+double libcolour_srgb_encode(double);
+double libcolour_srgb_decode(double);
+int libcolour_delta_e(const libcolour_colour_t*, const libcolour_colour_t*, double*);
+int libcolour_proper(libcolour_colour_t*);
+
+
+
+#endif
+
generated by cgit v1.2.3-70-g09d2 (git 2.47.0) at 2024-11-17 19:02:45 +0000