/**
* 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;
}
