/**
* Copyright © 2016 Mattias Andrée <maandree@member.fsf.org>
*
* 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 "libclut.h"
#include <errno.h>
/**
* Convert one component from [0, 1] linear RGB to [0, 1] sRGB.
*
* @param c The linear RGB value.
* @return Corresponding sRGB value.
*/
double (libclut_model_linear_to_standard1)(double c)
{
return libclut_model_linear_to_standard1(c);
}
/**
* Convert [0, 1] linear RGB to [0, 1] sRGB.
*
* @param r Pointer to the linear red component,
* and output parameter for the red component.
* @param g Pointer to the linear green component,
* and output parameter for the green component.
* @param b Pointer to the linear blue component,
* and output parameter for the blue component.
*/
void (libclut_model_linear_to_standard)(double* r, double* g, double* b)
{
libclut_model_linear_to_standard(r, g, b);
}
/**
* Convert one component from [0, 1] sRGB to [0, 1] linear RGB.
*
* @param c The sRGB value.
* @return Corresponding linear RGB value.
*/
double (libclut_model_standard_to_linear1)(double c)
{
return libclut_model_standard_to_linear1(c);
}
/**
* Convert [0, 1] sRGB to [0, 1] linear RGB.
*
* @param r Pointer to the red component, and output
* parameter for the linear red component.
* @param g Pointer to the green component, and output
* parameter for the linear green component.
* @param b Pointer to the blue component, and output
* parameter for the linear blue component.
*/
void (libclut_model_standard_to_linear)(double* r, double* g, double* b)
{
libclut_model_standard_to_linear(r, g, b);
}
/**
* Convert CIE xyY to CIE XYZ.
*
* @param x The x parameter.
* @param y The y parameter.
* @param Y The Y parameter. This is also the Y (middle) parameter for the CIE XYZ colour.
* @param X Output parameter for the X parameter.
* @param Z Output parameter for the Z parameter.
*/
void (libclut_model_ciexyy_to_ciexyz)(double x, double y, double Y, double* X, double* Z)
{
libclut_model_ciexyy_to_ciexyz(x, y, Y, X, Z);
}
/**
* Convert CIE XYZ to CIE xyY.
*
* @param X The X parameter.
* @param Y The Y parameter. This is also the Y (last) parameter for the CIE xyY colour.
* @param Z The Z parameter.
* @param x Output parameter for the x parameter.
* @param y Output parameter for the y parameter.
*/
void (libclut_model_ciexyz_to_ciexyy)(double X, double Y, double Z, double* x, double* y)
{
libclut_model_ciexyz_to_ciexyy(X, Y, Z, x, y);
}
/**
* Convert CIE XYZ to [0, 1] linear RGB.
*
* @param X The X parameter.
* @param Y The Y parameter.
* @param Z The Z parameter.
* @param r Output parameter for the red component.
* @param g Output parameter for the green component.
* @param b Output parameter for the blue component.
*/
void (libclut_model_ciexyz_to_linear)(double X, double Y, double Z, double* r, double* g, double* b)
{
libclut_model_ciexyz_to_linear(X, Y, Z, r, g, b);
}
/**
* Convert [0, 1] linear RGB to CIE XYZ.
*
* @param r The red component.
* @param g The green component.
* @param b The blue component.
* @param X Output parameter for the X parameter.
* @param Y Output parameter for the Y parameter.
* @param Z Output parameter for the Z parameter.
*/
void (libclut_model_linear_to_ciexyz)(double r, double g, double b, double* X, double* Y, double* Z)
{
libclut_model_linear_to_ciexyz(r, g, b, X, Y, Z);
}
/**
* Convert [0, 1] linear RGB to CIE xyY.
*
* @param r The red component.
* @param g The green component.
* @param b The blue component.
* @param x Output parameter for the x parameter.
* @param y Output parameter for the y parameter.
* @param Y Output parameter for the Y parameter.
*/
void (libclut_model_srgb_to_ciexyy)(double r, double g, double b, double* x, double* y, double* Y)
{
libclut_model_srgb_to_ciexyy(r, g, b, x, y, Y);
}
/**
* Convert CIE xyY to [0, 1] sRGB.
*
* @param x The x parameter.
* @param y The y parameter.
* @param Y The Y parameter.
* @param r Output parameter for the red component.
* @param g Output parameter for the green component.
* @param b Output parameter for the blue component.
*/
void (libclut_model_ciexyy_to_srgb)(double x, double y, double Y, double* r, double* g, double* b)
{
libclut_model_ciexyy_to_srgb(x, y, Y, r, g, b);
}
/**
* Convert from CIE XYZ to CIE L*a*b*.
*
* @param X The X parameter.
* @param Y The Y parameter.
* @param Z The Z parameter.
* @param L Output parameter for the L* component.
* @param a Output parameter for the a* component.
* @param b Output parameter for the b* component.
*/
void (libclut_model_ciexyz_to_cielab)(double X, double Y, double Z, double* L, double* a, double* b)
{
libclut_model_ciexyz_to_cielab(X, Y, Z, L, a, b);
}
/**
* Convert from CIE L*a*b* to CIE XYZ.
*
* @param L The L* component.
* @param a The a* component.
* @param b The b* component.
* @param X Output parameter for the X parameter.
* @param Y Output parameter for the Y parameter.
* @param Z Output parameter for the Z parameter.
*/
void (libclut_model_cielab_to_ciexyz)(double L, double a, double b, double* X, double* Y, double* Z)
{
libclut_model_cielab_to_ciexyz(L, a, b, X, Y, Z);
}
/**
* Divide all values in a row by a divisor.
*
* @param m The first part of the row.
* @param a The second part of the row.
* @param d The divisor.
*/
static void divrow(double m[3], double a[3], double d)
{
m[0] /= d, m[1] /= d, m[2] /= d;
a[0] /= d, a[1] /= d, a[2] /= d;
}
/**
* Subtract all values in a row by corresponding value
* in another row multiplied by a common value.
*
* @param a1 The first part of the minuend/difference row.
* @param a2 The second part of the minuend/difference row.
* @param b1 The first part of the subtrahend row.
* @param b2 The second part of the subtrahend row.
* @param m The multiplier.
*/
static void subrow(double a1[3], double a2[3], double b1[3], double b2[3], double m)
{
a1[0] -= b1[0] * m, a1[1] -= b1[1] * m, a1[2] -= b1[2] * m;
a2[0] -= b2[0] * m, a2[1] -= b2[1] * m, a2[2] -= b2[2] * m;
}
/**
* Invert a matrix.
*
* @param M The matrix to invert, will be modified to an
* identity matrix, possibly with reordered rows.
* @param A The inversion of M (as input).
* @return 1 on success, 0 if the matrix is not invertible.
*/
static int invert(libclut_colour_space_conversion_matrix_t M, libclut_colour_space_conversion_matrix_t A)
{
int r0 = 0, r1 = 1, r2 = 2, t, swapped = 0;
libclut_colour_space_conversion_matrix_t T;
A[0][0] = A[1][1] = A[2][2] = 1;
A[0][1] = A[0][2] = A[1][0] = A[1][2] = A[2][0] = A[2][1] = 0;
if (libclut_0__(M[r0][0]))
{
if (libclut_0__(M[r1][0]))
{
if (libclut_0__(M[r2][0]))
return 0;
t = r0, r0 = r2, r2 = t;
}
else
t = r0, r0 = r1, r1 = t;
swapped = 1;
}
divrow(M[r0], A[r0], M[r0][0]);
subrow(M[r1], A[r1], M[r0], A[r0], M[r1][0]);
subrow(M[r2], A[r2], M[r0], A[r0], M[r2][0]);
if (libclut_0__(M[r1][1]))
{
if (libclut_0__(M[r2][1]))
return 0;
t = r1, r1 = r2, r2 = t;
swapped = 1;
}
divrow(M[r1], A[r1], M[r1][1]);
subrow(M[r2], A[r2], M[r1], A[r1], M[r2][1]);
if (libclut_0__(M[r2][2]))
return 0;
divrow(M[r2], A[r2], M[r2][2]);
subrow(M[r1], A[r1], M[r2], A[r2], M[r1][2]);
subrow(M[r0], A[r0], M[r2], A[r2], M[r0][2]);
subrow(M[r0], A[r0], M[r1], A[r1], M[r0][1]);
if (swapped)
{
memcpy(T, A, sizeof(T));
memcpy(A[0], T[r0], sizeof(*T));
memcpy(A[1], T[r1], sizeof(*T));
memcpy(A[2], T[r2], sizeof(*T));
}
return 1;
}
/**
* Create an RGB to CIE XYZ conversion matrix.
*
* @param cs The colour space.
* @param M The output matrix.
* @return Zero on success, -1 on error.
*
* @throws EINVAL The colour space cannot be used.
*/
static int get_conversion_matrix(const libclut_rgb_colour_space_t* cs, libclut_colour_space_conversion_matrix_t M)
{
#define XYY_TO_XYZ(x, y, Y, Xp, Yp, Zp) \
(libclut_0__(Y)) ? \
(*(Xp) = *(Zp) = 0, *(Yp) = (Y)) : \
(*(Xp) = (x) * (Y) / (y), \
*(Yp) = (Y), \
*(Zp) = (1 - (x) - (y)) * (Y) / (y))
double Xr, Yr, Zr, Xg, Yg, Zg, Xb, Yb, Zb, Xw, Yw, Zw, Sr, Sg, Sb;
libclut_colour_space_conversion_matrix_t M2;
XYY_TO_XYZ(cs->red_x, cs->red_y, 1, &Xr, &Yr, &Zr);
XYY_TO_XYZ(cs->green_x, cs->green_y, 1, &Xg, &Yg, &Zg);
XYY_TO_XYZ(cs->blue_x, cs->blue_y, 1, &Xb, &Yb, &Zb);
XYY_TO_XYZ(cs->white_x, cs->white_y, cs->white_Y, &Xw, &Yw, &Zw);
M2[0][0] = Xr, M2[0][1] = Xg, M2[0][2] = Xb;
M2[1][0] = Yr, M2[1][1] = Yg, M2[1][2] = Yb;
M2[2][0] = Zr, M2[2][1] = Zg, M2[2][2] = Zb;
if (!invert(M2, M))
return errno = EINVAL, -1;
Sr = M[0][0] * Xw + M[0][1] * Yw + M[0][2] * Zw;
Sg = M[1][0] * Xw + M[1][1] * Yw + M[1][2] * Zw;
Sb = M[2][0] * Xw + M[2][1] * Yw + M[2][2] * Zw;
M[0][0] = Sr * Xr, M[0][1] = Sg * Xg, M[0][2] = Sb * Xb;
M[1][0] = Sr * Yr, M[1][1] = Sg * Yg, M[1][2] = Sb * Yb;
M[2][0] = Sr * Zr, M[2][1] = Sg * Zg, M[2][2] = Sb * Zb;
return 0;
#undef XYY_TO_XYZ
}
/**
* Create a matrix for converting values between
* two RGB colour spaces.
*
* @param from The input colour space, the Y-component is only necessary for the whitepoint.
* @param to The output colour space, the Y-component is only necessary for the whitepoint.
* @param M Output matrix for conversion from `from` to `to`.
* @param Minv Output matrix for conversion from `to` to `from`, may be `NULL`.
* @return Zero on success, -1 on error.
*
* @throws EINVAL The colour space cannot be used.
*/
int libclut_model_get_rgb_conversion_matrix(const libclut_rgb_colour_space_t* from,
const libclut_rgb_colour_space_t* to,
libclut_colour_space_conversion_matrix_t M,
libclut_colour_space_conversion_matrix_t Minv)
{
libclut_colour_space_conversion_matrix_t A, B;
if (get_conversion_matrix(from, A))
return -1;
if (get_conversion_matrix(to, M))
return -1;
if (!invert(M, B))
return errno = EINVAL, -1;
M[0][0] = B[0][0] * A[0][0] + B[0][1] * A[1][0] + B[0][2] * A[2][0];
M[0][1] = B[0][0] * A[0][1] + B[0][1] * A[1][1] + B[0][2] * A[2][1];
M[0][2] = B[0][0] * A[0][2] + B[0][1] * A[1][2] + B[0][2] * A[2][2];
M[1][0] = B[1][0] * A[0][0] + B[1][1] * A[1][0] + B[1][2] * A[2][0];
M[1][1] = B[1][0] * A[0][1] + B[1][1] * A[1][1] + B[1][2] * A[2][1];
M[1][2] = B[1][0] * A[0][2] + B[1][1] * A[1][2] + B[1][2] * A[2][2];
M[2][0] = B[2][0] * A[0][0] + B[2][1] * A[1][0] + B[2][2] * A[2][0];
M[2][1] = B[2][0] * A[0][1] + B[2][1] * A[1][1] + B[2][2] * A[2][1];
M[2][2] = B[2][0] * A[0][2] + B[2][1] * A[1][2] + B[2][2] * A[2][2];
if (Minv != NULL)
{
memcpy(A, M, sizeof(A));
if (!invert(A, Minv))
return errno = EINVAL, -1;
}
return 0;
}
/**
* Convert an RGB colour into another RGB colour space.
* None of the parameter may have side-effects.
*
* Both RGB colour space must have same gamma functions as RGB.
*
* @param r The red component of the colour to convert.
* @param g The green component of the colour to convert.
* @param b The blue component of the colour to convert.
* @param M Conversion matrix, create with `libclut_model_get_rgb_conversion_matrix`.
* @param out_r Output parameter for the new red component.
* @param out_g Output parameter for the new green component.
* @param out_b Output parameter for the new blue component.
*/
void (libclut_model_convert_rgb)(double r, double g, double b, libclut_colour_space_conversion_matrix_t M,
double *out_r, double *out_g, double *out_b)
{
libclut_model_convert_rgb(r, g, b, M, out_r, out_g, out_b);
}
