/**
* 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->R <= to->transition ? to->slope * to->R : (1 + to->offset) * pow(to->R, 1 / to->gamma) - to->offset;
to->G = to->G <= to->transition ? to->slope * to->G : (1 + to->offset) * pow(to->G, 1 / to->gamma) - to->offset;
to->B = 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->R <= to->transitioninv ? to->R * to->slope : pow((to->R + to->offset) / (1 + to->offset), to->gamma);
to->G = to->G <= to->transitioninv ? to->G * to->slope : pow((to->G + to->offset) / (1 + to->offset), to->gamma);
to->B = 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;
#define MULTIPLY(CX, CY, CZ) ((CX) * X + (CY) * Y + (CZ) * Z)
to->R = MULTIPLY(3.240446254647737500675930277794, -1.537134761820080575134284117667, -0.498530193022728718155178739835);
to->G = MULTIPLY(-0.969266606244679751469561779231, 1.876011959788370209167851498933, 0.041556042214430065351304932619);
to->B = MULTIPLY(0.055643503564352832235773149705, -0.204026179735960239147729566866, 1.057226567722703292062647051353);
#undef MULTIPLY
}
static inline double srgb_encode(double t)
{
double sign = 1;
if (t < 0) {
t = -t;
sign = -1;
}
t = t <= 0.0031306684425217108 ? 12.92 * t : 1.055 * pow(t, 1 / 2.4) - 0.055;
return t * sign;
}
static inline double srgb_decode(double t)
{
double sign = 1;
if (t < 0) {
t = -t;
sign = -1;
}
t = t <= 0.040448236277380506 ? t / 12.92 : pow((t + 0.055) / 1.055, 2.4);
return t * sign;
}
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 = srgb_encode(from->R);
to->G = srgb_encode(from->G);
to->B = srgb_encode(from->B);
} else {
to->R = srgb_decode(from->R);
to->G = srgb_decode(from->G);
to->B = 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 * 0.95629483232089407263032398986979387700557708740234 + Q * 0.62102512544472865396727456754888407886028289794922;
to->G = Y - I * 0.27212147408397735492968649850809015333652496337891 - Q * 0.64738095351761570928061928498209454119205474853516;
to->B = Y - I * 1.10698990856712820018969978264067322015762329101562 + Q * 1.70461497549882934343656870623817667365074157714844;
/* ⎛1 1000 cos 33° / 877 1000 sin 33° / 877 ⎞
⎜1 9500 sin 33° / 24067 - 299000 * cos 33° / 514799 -9500 cos 33° / 24067 - 299000 * sin 33° / 514799⎟
⎝1 -250 sin 33° / 123 250 cos 33° / 123 ⎠
*/
}
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;
}
#define MULTIPLIY(CR, CG, CB) ((CR) * R + (CG) * G + (CB) * B)
to->X = MULTIPLIY(0.412457445582367576708548995157, 0.357575865245515878143578447634, 0.180437247826399665973085006954);
to->Y = MULTIPLIY(0.212673370378408277403536885686, 0.715151730491031756287156895269, 0.072174899130559869164791564344);
to->Z = MULTIPLIY(0.019333942761673460208893260415, 0.119191955081838593666354597644, 0.950302838552371742508739771438);
#undef MULTIPLIY
}
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 * 0.299 + g * 0.587 + b * 0.114;
to->I = r * 0.59571613491277464191853141528554260730743408203125 /* (0.877 cos 33°)(1 - 0.299) - (0.492 sin 33°)(-0.299) */
- g * 0.27445283783925644716106262421817518770694732666016 /* (0.877 cos 33°)(-0.587) - (0.492 sin 33°)(-0.587) */
- b * 0.32126329707351808373516632855171337723731994628906; /* (0.877 cos 33°)(-0.114) - (0.492 sin 33°)(1 - 0.114) */
to->Q = r * 0.21145640212011795888713550084503367543220520019531 /* (0.877 sin 33°)(1 - 0.299) + (0.492 cos 33°)(-0.299) */
- g * 0.52259104529161115593183239980135113000869750976562 /* (0.877 sin 33°)(-0.587) + (0.492 cos 33°)(-0.587) */
+ b * 0.31113464317149330806699936147197149693965911865234; /* (0.877 sin 33°)(-0.114) + (0.492 cos 33°)(1 - 0.114) */
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;
}
