libclut.c

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

2 files changed, 423 insertions, 0 deletions

diff --git a/src/libclut.c b/src/libclut.c
new file mode 100644
index 0000000..dc9294c
--- /dev/null
+++ b/src/libclut.c
@@ -0,0 +1,258 @@
+/**
+ * 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"
+
+
+
+/**
+ * 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 (c <= 0.0031308) ? (12.92 * c) : ((1.0 + 0.055) * pow(c, 1.0 / 2.4));
+}
+
+
+/**
+ * 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)
+{
+  *r = libclut_model_linear_to_standard1(*r):
+  *g = libclut_model_linear_to_standard1(*g);
+  *b = libclut_model_linear_to_standard1(*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 (c <= 0.04045) ? (c / 12.92) : pow((c + 0.055) / (1.0 + 0.055), 2.4);
+}
+
+
+/**
+ * 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)
+{
+  *r = libclut_model_standard_to_linear1(*r):
+  *g = libclut_model_standard_to_linear1(*g);
+  *b = libclut_model_standard_to_linear1(*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)
+{
+  *X = (y == 0.0) ? Y : (Y * x / y);
+  *Z = (y == 0.0) ? Y : (Y * (1 - x - y) / y);
+}
+
+
+/**
+ * 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)
+{
+  double s = X + Y + Z;
+  if (s == 0.0)
+    *x = *y = 0.0;
+  else
+    *x = X / s, *y = Y / s;
+}
+
+
+/**
+ * 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)
+{
+  *r = ( 3.2404500 * X) + (-1.537140 * Y) + (-0.4985320 * Z);
+  *g = (-0.9692660 * X) + ( 1.876010 * Y) + ( 0.0415561 * Z);
+  *b = ( 0.0556434 * X) + (-0.204026 * Y) + ( 1.0572300 * Z);
+}
+
+
+/**
+ * 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)
+{
+  *X = (0.4124564 * r) + (0.3575761 * g) + (0.1804375 * b);
+  *Y = (0.2126729 * r) + (0.7151522 * g) + (0.0721750 * b);
+  *Z = (0.0193339 * r) + (0.1191920 * g) + (0.9503041 * b);
+}
+
+
+/**
+ * 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)
+{
+  double X, Z;
+  libclut_model_standard_to_linear(&r, &g, &b);
+  libclut_model_linear_to_ciexyz(r, g, b, &X, Y, &Z);
+  libclut_model_ciexyz_to_ciexyy(X, *Y, Z, x, 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)
+{
+  double X, Z;
+  libclut_model_ciexyy_to_ciexyz(x, y, Y, &X, &Z);
+  libclut_model_ciexyz_to_linear(X, *Y, Z, r, g, b);
+  libclut_model_linear_to_standard(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)
+{
+#define F(C)  ((C) > 0.00885642) ? pow((C), 1.0 / 3.0) : ((7.78 + 703.0 / 99900.0) * (C) + 0.1379310)
+  X /= 0.95047, Z /= 1.08883;
+  X = F(X), Y = F(Y), Z = F(Z);
+  *L = 116.0 * Y - 16.0;
+  *a = 500.0 * (X - Y);
+  *b = 200.0 * (Y - Z);
+#undef F
+}
+
+
+/**
+ * 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_xiexyz(double L, double a, double b, double* X, double* Y, double* Z)
+{
+#define F(C)  (((C)*(C)*(C) > 0.00885642) ? ((C)*(C)*(C)) : (((C) - 0.1379310) / (7.78 + 703.0 / 99900.0)))
+    *Y = (l + 16.0) / 116.0;
+    *X = a / 500.0 + *Y;
+    *Z = *Y - b / 200.0;
+    *X = F(*X) * 0.95047;
+    *Y = F(*Y);
+    *Z = F(*Z) * 1.08883;
+#undef F
+}
+
+
+/**
+ * Convert the distance (∆E*_ab) between two [0, 1] sRGB colours.
+ * 
+ * @param   r1  The red component of the first colour.
+ * @param   g1  The green component of the first colour.
+ * @param   b1  The blue component of the first colour.
+ * @param   r2  The red component of the second colour.
+ * @param   g2  The green component of the second colour.
+ * @param   b2  The blue component of the second colour.
+ * @return      The difference.
+ */
+double libclut_model_delta_e(double r1, double g1, double b1, double r2, double g2, double b2)
+{
+  double X1, Y1, Z1,     L1, a1, b1,            X2, Y2, Z2,     L2, a2, b2;
+  standard_to_linear(&r1, &g1, &b1),            standard_to_linear(&r2, &g2, &b2);
+  linear_to_ciexyz(r1, g1, b1, &X1, &Y1, &Z1),  linear_to_ciexyz(r2, g2, b2, &X2, &Y2, &Z2);
+  ciexyz_to_cielab(X1, Y1, Z1, &L1, &a1, &b1),  ciexyz_to_cielab(X2, Y2, Z2, &L2, &a2, &b2);
+  L1 -= L2,  L1 *= L1;
+  a1 -= a2,  a1 *= a1;
+  b1 -= b2,  b1 *= b1;
+  return L1 + a1 + b1;
+}
+
diff --git a/src/libclut.h b/src/libclut.h
index d4c76dd..4670c16 100644
--- a/src/libclut.h
+++ b/src/libclut.h
@@ -748,5 +748,170 @@
 
 
 
+#if __GNUC__
+#define LIBCLUT_GCC_ONLY__(x)  x
+#else
+#define LIBCLUT_GCC_ONLY__(x)  /* do nothing */
+#endif
+
+
+/**
+ * Convert one component from [0, 1] linear RGB to [0, 1] sRGB.
+ * 
+ * @param   c  The linear RGB value.
+ * @return     Corresponding sRGB value.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((const, leaf)))
+double libclut_model_linear_to_standard1(double 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);
+
+/**
+ * Convert one component from [0, 1] sRGB to [0, 1] linear RGB.
+ * 
+ * @param   c  The sRGB value.
+ * @return     Corresponding linear RGB value.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((const, leaf)))
+double libclut_model_standard_to_linear1(double 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);
+
+/**
+ * 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.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((leaf)))
+void libclut_model_ciexyy_to_ciexyz(double x, double y, double Y, double* X, double* 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.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((leaf)))
+void libclut_model_ciexyz_to_ciexyy(double X, double Y, double Z, double* x, double* 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.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((leaf)))
+void libclut_model_ciexyz_to_linear(double X, double Y, double Z, double* r, double* g, double* 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.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((leaf)))
+void libclut_model_linear_to_ciexyz(double r, double g, double b, double* X, double* Y, double* 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);
+
+/**
+ * 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);
+
+/**
+ * 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.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((leaf)))
+void libclut_model_ciexyz_to_cielab(double X, double Y, double Z, double* L, double* a, double* 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.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((leaf)))
+void libclut_model_cielab_to_xiexyz(double L, double a, double b, double* X, double* Y, double* Z);
+
+/**
+ * Convert the distance (∆E*_ab) between two [0, 1] sRGB colours.
+ * 
+ * @param   r1  The red component of the first colour.
+ * @param   g1  The green component of the first colour.
+ * @param   b1  The blue component of the first colour.
+ * @param   r2  The red component of the second colour.
+ * @param   g2  The green component of the second colour.
+ * @param   b2  The blue component of the second colour.
+ * @return      The difference.
+ */
+double libclut_model_delta_e(double r1, double g1, double b1, double r2, double g2, double b2);
+
+
+
 #endif