Add libclut_model_rgb_to_ciexyz and libclut_model_ciexyz_to_rgb

Signed-off-by: Mattias Andrée <maandree@kth.se>

5 files changed, 308 insertions, 33 deletions

diff --git a/NEWS b/NEWS
index 8f651d3..1cefe93 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,12 @@ libclut NEWS                                          -*- outline -*-
 
   New RGB colour spaces added: ITU-R BT.709 and Lightroom RGB.
 
+  libclut_model_get_rgb_conversion_matrix accepts NULL as
+  as the first and second argument.
+
+  Add the functions libclut_model_rgb_to_xyz and
+  libclut_model_rgb_to_xyz.
+
 * Noteworthy changes in release 1.0 (2016-(12)Dec-02) [stable]
 
   RGB colour space conversion added.
diff --git a/doc/info/chap/colour-spaces.texinfo b/doc/info/chap/colour-spaces.texinfo
index e1dfae1..b190ada 100644
--- a/doc/info/chap/colour-spaces.texinfo
+++ b/doc/info/chap/colour-spaces.texinfo
@@ -895,9 +895,11 @@ This function is not available as a macro, thus, linking with
 Parameters:
 @table @code
 @item const libclut_rgb_colour_space_t* from
-Description of the input colour space.
+Description of the input colour space. CIE XYZ is
+used use if this parameter is @code{NULL}.
 @item const libclut_rgb_colour_space_t* to
-Description of the output colour space.
+Description of the output colour space. CIE XYZ is
+used use if this parameter is @code{NULL}.
 @item libclut_colour_space_conversion_matrix_t M
 Matrix to fill with values so it can be used for
 converting from the input colour space to the
@@ -923,7 +925,7 @@ function.
 @table @code
 @item libclut_model_convert_rgb(r, g, b, M, *out_r, *out_g, *out_b)
 Convert a single RGB colour into another RGB colour space.
-The colour space must have same gamma functions as RGB.
+The colour space must have same gamma functions as sRGB.
 
 This macro is also available a function. If the function is
 used, linking with @option{-lclut} is required, otherwise,
@@ -949,6 +951,7 @@ Output parameter for the green value of the colour after conversion.
 Output parameter for the blue value of the colour after conversion.
 @end table
 
+
 @item libclut_convert_rgb_inplace(clut, max, type, m, trunc)
 Convert the curves between two RGB colour spaces.
 
@@ -986,6 +989,7 @@ out of gamut are truncated. (Not necessarily the best
 approximation.)
 @end table
 
+
 @item libclut_convert_rgb(clut, max, type, m, trunc, out)
 Convert the curves between two RGB colour spaces.
 
@@ -1031,3 +1035,68 @@ the same data type as @code{clut}. And have the same values on
 @code{clut}.
 @end table
 @end table
+
+There is also two functions for converting between a custom RGB
+colour space and CIE XYZ, one function in each direction. Note
+that the three functions above do not work if one of the colour
+spaces is CIE XYZ.
+
+@table @code
+@item libclut_model_rgb_to_ciexyz(r, g, b, M, *X, *Y, *Z)
+Convert a single RGB colour if a custom RGB colour space
+to CIE XYZ.
+
+The RGB colour space must have the same gamma function as sRGB.
+
+This macro is also available a function. If the function is
+used, linking with @option{-lclut} is required, otherwise,
+linking with @option{-lm} is required, or @option{-lclut} if
+@code{libclut_model_standard_to_linear1} is undefined.
+
+Parameters:
+@table @code
+@item double r
+The red component.
+@item double g
+The green component.
+@item double b
+The blue component.
+@item libclut_colour_space_conversion_matrix_t M
+The conversion matrix.
+@item double* X
+Output parameter for the X component.
+@item double* Y
+Output parameter for the Y component.
+@item double* Z
+Output parameter for the Z component.
+@end table
+
+
+@item libclut_model_rgb_to_ciexyz(X, Y, Z, M, *r, *g, *b)
+Convert a single colour from CIE XYZ to a custom RGB colour space.
+
+The RGB colour space must have the same gamma function as sRGB.
+
+This macro is also available a function. If the function is
+used, linking with @option{-lclut} is required, otherwise,
+linking with @option{-lm} is required, or @option{-lclut} if
+@code{libclut_model_linear_to_standard1} is undefined.
+
+Parameters:
+@table @code
+@item double X
+The X component.
+@item double Y
+The Y component.
+@item double Z
+The Z component.
+@item libclut_colour_space_conversion_matrix_t M
+The conversion matrix.
+@item double* r
+Output parameter for the red component.
+@item double* g
+Output parameter for the green component.
+@item double* b
+Output parameter for the blue component.
+@end table
+@end table
diff --git a/src/libclut.c b/src/libclut.c
index 9395c71..52c9615 100644
--- a/src/libclut.c
+++ b/src/libclut.c
@@ -647,8 +647,10 @@ static int get_conversion_matrix(const libclut_rgb_colour_space_t* cs, libclut_c
  * 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   from  The input colour space, the Y-component is only necessary
+ *                for the white point, `NULL` for CIE XYZ.
+ * @param   to    The output colour space, the Y-component is only necessary
+ *                for the white point, `NULL` for CIE XYZ.
  * @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.
@@ -662,24 +664,44 @@ int libclut_model_get_rgb_conversion_matrix(const libclut_rgb_colour_space_t* fr
 {
   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];
+  if (from != NULL)
+    {
+      if (get_conversion_matrix(from, A))
+	return -1;
+    }
+  else
+    {
+      A[0][0] = A[1][1] = A[2][2] = 1;
+      A[0][1] = A[1][0] = A[2][0] = 0;
+      A[0][2] = A[1][2] = A[2][1] = 0;
+    }
   
-  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 (to != NULL)
+    {
+      if (get_conversion_matrix(to, M))
+	return -1;
+      if (!invert(M, B))
+	return errno = EINVAL, -1;
+      
+      if (from != NULL)
+	{
+	  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];
+	}
+      else
+	memcpy(M, B, sizeof(B));
+    }
+  else
+    memcpy(M, A, sizeof(A));
   
   if (Minv != NULL)
     {
@@ -694,9 +716,8 @@ int libclut_model_get_rgb_conversion_matrix(const libclut_rgb_colour_space_t* fr
 
 /**
  * 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.
+ * Both RGB colour spaces must have same gamma functions as sRGB.
  * 
  * @param  r      The red component of the colour to convert.
  * @param  g      The green component of the colour to convert.
@@ -712,3 +733,43 @@ void (libclut_model_convert_rgb)(double r, double g, double b, libclut_colour_sp
   libclut_model_convert_rgb(r, g, b, M, out_r, out_g, out_b);
 }
 
+
+/**
+ * Convert an RGB colour of a custom RGB colour space to CIE XYZ.
+ * 
+ * The RGB colour space must have same gamma functions as sRGB.
+ * 
+ * @param  r  The red component.
+ * @param  g  The green component.
+ * @param  b  The blue component.
+ * @param  M  Conversion matrix, create with `libclut_model_get_rgb_conversion_matrix`.
+ * @param  x  Output parameter for the X component.
+ * @param  y  Output parameter for the Y component.
+ * @param  z  Output parameter for the Z component.
+ */
+void (libclut_model_rgb_to_ciexyz)(double r, double g, double b, libclut_colour_space_conversion_matrix_t M,
+				   double* x, double* y, double* z)
+{
+  libclut_model_rgb_to_ciexyz(r, g, b, M, x, y, z);
+}
+
+
+/**
+ * Convert a CIE XYZ colour to a custom RGB colour space.
+ * 
+ * The RGB colour space must have same gamma functions as sRGB.
+ * 
+ * @param  x  The X component.
+ * @param  y  The Y component.
+ * @param  z  The Z component.
+ * @param  M  Conversion matrix, create with `libclut_model_get_rgb_conversion_matrix`.
+ * @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_rgb)(double x, double y, double z, libclut_colour_space_conversion_matrix_t M,
+				   double* r, double* g, double* b)
+{
+  libclut_model_ciexyz_to_rgb(x, y, z, M, r, g, b);
+}
+
diff --git a/src/libclut.h b/src/libclut.h
index e1601f1..7c0dcd8 100644
--- a/src/libclut.h
+++ b/src/libclut.h
@@ -630,7 +630,7 @@ static inline int libclut_0__(double x)  {  return libclut_eq__(x, 0);  }
 /**
  * Convert the curves between two RGB colour spaces.
  * 
- * Both RGB colour space must have same gamma functions as sRGB.
+ * Both RGB colour spaces must have same gamma functions as sRGB.
  * 
  * Requires that `clut->red_size`, `clut->green_size`
  * and `clut->blue_size` are equal.
@@ -692,7 +692,7 @@ static inline int libclut_0__(double x)  {  return libclut_eq__(x, 0);  }
 /**
  * Convert the curves between two RGB colour spaces.
  * 
- * Both RGB colour space must have same gamma functions as sRGB.
+ * Both RGB colour spaces must have same gamma functions as sRGB.
  * 
  * None of the parameter may have side-effects.
  * 
@@ -1871,7 +1871,7 @@ void (libclut_model_linear_to_ciexyz)(double, double, double, double*, double*,
 
 
 /**
- * Convert [0, 1] linear sRGB to CIE xyY.
+ * Convert [0, 1] sRGB to CIE xyY.
  * 
  * The macro variant requires linking with '-lclut'
  * if any of `libclut_model_ciexyz_to_ciexyy`,
@@ -2499,8 +2499,10 @@ void (libclut_model_cie_1960_ucs_to_cieuvw)(double, double, double, double, doub
  * 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   from  The input colour space, the Y-component is only necessary
+ *                for the white point, `NULL` for CIE XYZ.
+ * @param   to    The output colour space, the Y-component is only necessary
+ *                for the white point, `NULL` for CIE XYZ.
  * @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.
@@ -2517,7 +2519,7 @@ int libclut_model_get_rgb_conversion_matrix(const libclut_rgb_colour_space_t*,
 /**
  * Convert an RGB colour into another RGB colour space.
  * 
- * Both RGB colour space must have same gamma functions as RGB.
+ * Both RGB colour spaces must have same gamma functions as sRGB.
  * 
  * Requires linking with '-lclut', or '-lm' if
  * `libclut_model_standard_to_linear1` or
@@ -2527,7 +2529,7 @@ int libclut_model_get_rgb_conversion_matrix(const libclut_rgb_colour_space_t*,
  * @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`,
- *                must not have side-effects (unless libclut_model_convert_rgb1 is undefined).
+ *                must not have side-effects.
  * @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.
@@ -2548,6 +2550,70 @@ void (libclut_model_convert_rgb)(double, double, double, libclut_colour_space_co
   while (0)
 
 
+/**
+ * Convert an RGB colour of a custom RGB colour space to CIE XYZ.
+ * 
+ * The RGB colour space must have same gamma functions as sRGB.
+ * 
+ * Requires linking with '-lclut', or '-lm' if
+ * `libclut_model_standard_to_linear1` is not undefined.
+ * 
+ * @param  r  The red component.
+ * @param  g  The green component.
+ * @param  b  The blue component.
+ * @param  M  Conversion matrix, create with `libclut_model_get_rgb_conversion_matrix`,
+ *            must not have side-effects.
+ * @param  x  Output parameter for the X component.
+ * @param  y  Output parameter for the Y component
+ * @param  z  Output parameter for the Z component.
+ */
+LIBCLUT_GCC_ONLY__(__attribute__((__leaf__)))
+void (libclut_model_rgb_to_ciexyz)(double, double, double, libclut_colour_space_conversion_matrix_t,
+				   double*, double*, double*);
+#define libclut_model_rgb_to_ciexyz(r, g, b, M, x, y, z)		\
+  do									\
+    {									\
+      double r__ = libclut_model_standard_to_linear1(r);		\
+      double g__ = libclut_model_standard_to_linear1(g);		\
+      double b__ = libclut_model_standard_to_linear1(b);		\
+      *(x) = (M)[0][0] * r__ + (M)[0][1] * g__ + (M)[0][2] * b__;	\
+      *(y) = (M)[1][0] * r__ + (M)[1][1] * g__ + (M)[1][2] * b__;	\
+      *(z) = (M)[2][0] * r__ + (M)[2][1] * g__ + (M)[2][2] * b__;	\
+    }									\
+  while (0)
+
+
+/**
+ * Convert a CIE XYZ colour to a custom RGB colour space.
+ * 
+ * The RGB colour space must have same gamma functions as sRGB.
+ * 
+ * Requires linking with '-lclut', or '-lm' if
+ * `libclut_model_linear_to_standard1` is not undefined.
+ * 
+ * @param  x  The X component.
+ * @param  y  The Y component.
+ * @param  z  The Z component.
+ * @param  M  Conversion matrix, create with `libclut_model_get_rgb_conversion_matrix`,
+ *            must not have side-effects.
+ * @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_rgb)(double, double, double, libclut_colour_space_conversion_matrix_t,
+				   double*, double*, double*);
+#define libclut_model_ciexyz_to_rgb(x, y, z, M, r, g, b)						\
+  do													\
+    {													\
+      double x__ = (x), y__ = (y), z__ = (z);								\
+      *(r) = libclut_model_linear_to_standard1((M)[0][0] * x__ + (M)[0][1] * y__ + (M)[0][2] * z__);	\
+      *(g) = libclut_model_linear_to_standard1((M)[1][0] * x__ + (M)[1][1] * y__ + (M)[1][2] * z__);	\
+      *(b) = libclut_model_linear_to_standard1((M)[2][0] * x__ + (M)[2][1] * y__ + (M)[2][2] * z__);	\
+    }													\
+  while (0)
+
+
 
 #if defined(__clang__)
 # pragma GCC diagnostic pop
diff --git a/src/test.c b/src/test.c
index b4491a8..28e8e7d 100644
--- a/src/test.c
+++ b/src/test.c
@@ -145,7 +145,7 @@ int main(int argc, char *argv[])
   struct dclut d1, d2;
   size_t i, j;
   int rc = 0;
-  double param, r, g, b;
+  double param, r, g, b, x, y, z;
   
   t1.  red_size = t2.  red_size = t3.  red_size = d1.  red_size = d2.  red_size = 256;
   t1.green_size = t2.green_size = t3.green_size = d1.green_size = d2.green_size = 256;
@@ -360,11 +360,84 @@ int main(int argc, char *argv[])
   
   libclut_convert_rgb_inplace(&t1, 1, double, M, trunc); /* TODO test */
   libclut_convert_rgb(&t1, 1, double, M, trunc, &t2);    /* TODO test */
+
   
+  if (libclut_model_get_rgb_conversion_matrix(&srgb, NULL, M, Minv))
+    {
+      printf("libclut_model_get_rgb_conversion_matrix failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
+  libclut_model_rgb_to_ciexyz(0.1, 0.5, 0.9, M, &x, &y, &z);
+  if (0.2227 > x || x > 0.2228 ||
+      0.2120 > y || y > 0.2121 ||
+      0.7739 > z || z > 0.7741)
+    {
+      printf("libclut_model_get_rgb_conversion_matrix or libclut_model_rgb_to_ciexyz failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
+  libclut_model_ciexyz_to_rgb(x, y, z, Minv, &r, &g, &b);
+  if (0.0999 > r || r > 1.0001 ||
+      0.4999 > g || g > 0.5001 ||
+      0.8999 > b || b > 0.9001)
+    {
+      printf("libclut_model_get_rgb_conversion_matrix or libclut_model_ciexyz_to_rgb failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
   
- rgb_conversion_done:
+  
+  if (libclut_model_get_rgb_conversion_matrix(NULL, &srgb, Minv, M))
+    {
+      printf("libclut_model_get_rgb_conversion_matrix failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
+  libclut_model_rgb_to_ciexyz(0.1, 0.5, 0.9, M, &r, &g, &b);
+  libclut_model_ciexyz_to_rgb(r, g, b, Minv, &r, &g, &b);
+  if (0.0999 > r || r > 1.0001 ||
+      0.4999 > g || g > 0.5001 ||
+      0.8999 > b || b > 0.9001)
+    {
+      printf("libclut_model_get_rgb_conversion_matrix failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
 
   
+  if (libclut_model_get_rgb_conversion_matrix(NULL, NULL, M, Minv))
+    {
+      printf("libclut_model_get_rgb_conversion_matrix failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
+  if (0.999999 > M[0][0] || M[0][0] > 1.000001 ||
+      -.999999 > M[0][1] || M[0][1] > 0.000001 ||
+      -.999999 > M[0][2] || M[0][2] > 0.000001 ||
+      -.999999 > M[1][0] || M[1][0] > 0.000001 ||
+      0.999999 > M[1][1] || M[1][1] > 1.000001 ||
+      -.999999 > M[1][2] || M[1][2] > 0.000001 ||
+      -.999999 > M[2][0] || M[2][0] > 0.000001 ||
+      -.999999 > M[2][1] || M[2][1] > 0.000001 ||
+      0.999999 > M[2][2] || M[2][2] > 1.000001)
+    {
+      printf("libclut_model_get_rgb_conversion_matrix failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
+  if (0.999999 > Minv[0][0] || Minv[0][0] > 1.000001 ||
+      -.999999 > Minv[0][1] || Minv[0][1] > 0.000001 ||
+      -.999999 > Minv[0][2] || Minv[0][2] > 0.000001 ||
+      -.999999 > Minv[1][0] || Minv[1][0] > 0.000001 ||
+      0.999999 > Minv[1][1] || Minv[1][1] > 1.000001 ||
+      -.999999 > Minv[1][2] || Minv[1][2] > 0.000001 ||
+      -.999999 > Minv[2][0] || Minv[2][0] > 0.000001 ||
+      -.999999 > Minv[2][1] || Minv[2][1] > 0.000001 ||
+      0.999999 > Minv[2][2] || Minv[2][2] > 1.000001)
+    {
+      printf("libclut_model_get_rgb_conversion_matrix failed\n"), rc = 1;
+      goto rgb_conversion_done;
+    }
+  
+  
+  libclut_model_get_rgb_conversion_matrix(&srgb, &wgrgb, M, NULL); /* Just testing that we don't get a segfault. */
+ rgb_conversion_done:
+  
+  
   libclut_model_ciexyz_to_cieluv(1, 1, 1, 1, 1, 1, &r, &g, &b); /* TODO test */
   libclut_model_cieluv_to_ciexyz(1, 1, 1, 1, 1, 1, &r, &g, &b); /* TODO test */
   libclut_model_cielch_to_cieluv(1, 1, &r, &g); /* TODO test */