diff options
| -rw-r--r-- | libglitter.h | 8 | ||||
| -rw-r--r-- | libglitter_colour_space_convert_rasters_double.c | 14 | ||||
| -rw-r--r-- | libglitter_get_colour_space_conversion_matrix_double.c | 48 |
3 files changed, 34 insertions, 36 deletions
diff --git a/libglitter.h b/libglitter.h index 649d522..7e2a1ea 100644 --- a/libglitter.h +++ b/libglitter.h @@ -272,9 +272,11 @@ void libglitter_per_channel_desaturate_float(float **, size_t, size_t, size_t, s * uses some other colour space, this function can output * the conversion matrix for the CIE XYZ colour space, * which can that be right-hand multiplied to get the - * conversion matrix for some other colour + * conversion matrix for some other colour; but be aware + * that the output matrix is in column-major order, not + * row-major order * - * @param matrix Output buffer for the conversion matrix + * @param matrix Output buffer for the conversion matrix, in column-major order * @param c1x The CIE x value (as in CIE xyY) of the output's first primary colour * @param c1y The CIE y value (as in CIE xyY) of the output's first primary colour * @param c2x The CIE x value (as in CIE xyY) of the output's second primary colour @@ -329,7 +331,7 @@ void libglitter_get_colour_space_conversion_matrix_float(float[3][3], float, flo * values per cell) * @param width The horizontal number of pixels in the rasters * @param height The vertical number of pixels in the rasters - * @param matrix Colour space conversion matrix + * @param matrix Colour space conversion matrix, in column-major order */ void libglitter_colour_space_convert_rasters_double(size_t n, size_t m, double **, const double **, size_t, size_t, size_t, size_t, size_t, size_t, const double[n][m]); diff --git a/libglitter_colour_space_convert_rasters_double.c b/libglitter_colour_space_convert_rasters_double.c index 7128998..3923911 100644 --- a/libglitter_colour_space_convert_rasters_double.c +++ b/libglitter_colour_space_convert_rasters_double.c @@ -6,9 +6,9 @@ static void multiply_33(double **outputs, size_t opos, const double **inputs, size_t ipos, const double matrix[3][3]) { double i0 = inputs[0][ipos], i1 = inputs[1][ipos], i2 = inputs[2][ipos]; - outputs[0][opos] = i0 * matrix[0][0] + i1 * matrix[1][0] + i2 * matrix[2][0]; - outputs[1][opos] = i0 * matrix[0][1] + i1 * matrix[1][1] + i2 * matrix[2][1]; - outputs[2][opos] = i0 * matrix[0][2] + i1 * matrix[1][2] + i2 * matrix[2][2]; + outputs[0][opos] = i0 * matrix[0][0] + i1 * matrix[0][1] + i2 * matrix[0][2]; + outputs[1][opos] = i0 * matrix[1][0] + i1 * matrix[1][1] + i2 * matrix[1][2]; + outputs[2][opos] = i0 * matrix[2][0] + i1 * matrix[2][1] + i2 * matrix[2][2]; } @@ -20,9 +20,9 @@ multiply_nn(size_t n, double **outputs, size_t opos, const double **inputs, size for (j = 0; j < n; j++) buffer[j] = inputs[j][ipos]; for (i = 0; i < n; i++) { - outputs[i][opos] = buffer[0] * matrix[0][i]; + outputs[i][opos] = buffer[0] * matrix[i][0]; for (j = 1; j < n; j++) - outputs[i][opos] += buffer[j] * matrix[j][i]; + outputs[i][opos] += buffer[j] * matrix[i][j]; } } @@ -35,9 +35,9 @@ multiply_nm(size_t n, size_t m, double **outputs /* m */, size_t opos, const dou for (j = 0; j < n; j++) buffer[j] = inputs[j][ipos]; for (i = 0; i < m; i++) { - outputs[i][opos] = buffer[0] * matrix[0][i]; + outputs[i][opos] = buffer[0] * matrix[i][0]; for (j = 1; j < n; j++) - outputs[i][opos] += buffer[j] * matrix[j][i]; + outputs[i][opos] += buffer[j] * matrix[i][j]; } } diff --git a/libglitter_get_colour_space_conversion_matrix_double.c b/libglitter_get_colour_space_conversion_matrix_double.c index 3ee734d..e0f6aa1 100644 --- a/libglitter_get_colour_space_conversion_matrix_double.c +++ b/libglitter_get_colour_space_conversion_matrix_double.c @@ -12,12 +12,13 @@ /** - * CIE XYZ-to-sRGB conversion matrix + * CIE XYZ-to-sRGB conversion matrix, + * in column-major order */ static const double srgb[3][3] = { - { 3.240446254647737056586720427731, -1.537134761820080353089679192635, -0.498530193022728773666329971093}, - {-0.969266606244679751469561779231, 1.876011959788370209167851498933, 0.041556042214430065351304932619}, - { 0.055643503564352832235773149705, -0.204026179735960239147729566866, 1.057226567722703292062647051353}}; + { 3.240446254647737056586720427731, -0.969266606244679751469561779231, 0.055643503564352832235773149705}, + {-1.537134761820080353089679192635, 1.876011959788370209167851498933, -0.204026179735960239147729566866}, + {-0.498530193022728773666329971093, 0.041556042214430065351304932619, 1.057226567722703292062647051353}}; #if defined(__GNUC__) && !defined(__clang__) @@ -26,7 +27,7 @@ static const double srgb[3][3] = { static void -invert(double m[3][4]) +invert(double m[3][4]) /* row-major order */ { double t; size_t i; @@ -55,7 +56,7 @@ libglitter_get_colour_space_conversion_matrix_double(double matrix[3][3], double double y1, y2, y3; double z1, z2, z3; - /* Get colour space in CIE XYZ */ + /* Get colour space in CIE XYZ (the matrix is in row-major order) */ mat[0][0] = x1 = X(c1x, c1y); mat[0][1] = x2 = X(c2x, c2y); mat[0][2] = x3 = X(c3x, c3y); @@ -73,30 +74,25 @@ libglitter_get_colour_space_conversion_matrix_double(double matrix[3][3], double y2 = mat[1][3]; y3 = mat[2][3]; - /* [[x1, x2, x3], [y1, y2, y3], [z1, z2, z3]] is + /* [x1, x2, x3; y1, y2, y3; z1, z2, z3] is * the output RGB-to-CIE XYZ conversion matrix. * If sRGB is desired, it is multiplied by the * CIE XYZ-to-sRGB conversion matrix to get the - * output RGB-to-sRGB conversion matrix. */ + * output RGB-to-sRGB conversion matrix. The + * matrices are in column-major order. */ if (!xyz) { - matrix[0][0] = x1 * srgb[0][0] + x2 * srgb[1][0] + x3 * srgb[2][0]; - matrix[0][1] = x1 * srgb[0][1] + x2 * srgb[1][1] + x3 * srgb[2][1]; - matrix[0][2] = x1 * srgb[0][2] + x2 * srgb[1][2] + x3 * srgb[2][2]; - matrix[1][0] = y1 * srgb[0][0] + y2 * srgb[1][0] + y3 * srgb[2][0]; - matrix[1][1] = y1 * srgb[0][1] + y2 * srgb[1][1] + y3 * srgb[2][1]; - matrix[1][2] = y1 * srgb[0][2] + y2 * srgb[1][2] + y3 * srgb[2][2]; - matrix[2][0] = z1 * srgb[0][0] + z2 * srgb[1][0] + z3 * srgb[2][0]; - matrix[2][1] = z1 * srgb[0][1] + z2 * srgb[1][1] + z3 * srgb[2][1]; - matrix[2][2] = z1 * srgb[0][2] + z2 * srgb[1][2] + z3 * srgb[2][2]; + matrix[0][0] = x1 * srgb[0][0] + x2 * srgb[0][1] + x3 * srgb[0][2]; + matrix[1][0] = x1 * srgb[1][0] + x2 * srgb[1][1] + x3 * srgb[1][2]; + matrix[2][0] = x1 * srgb[2][0] + x2 * srgb[2][1] + x3 * srgb[2][2]; + matrix[0][1] = y1 * srgb[0][0] + y2 * srgb[0][1] + y3 * srgb[0][2]; + matrix[1][1] = y1 * srgb[1][0] + y2 * srgb[1][1] + y3 * srgb[1][2]; + matrix[2][1] = y1 * srgb[2][0] + y2 * srgb[2][1] + y3 * srgb[2][2]; + matrix[0][2] = z1 * srgb[0][0] + z2 * srgb[0][1] + z3 * srgb[0][2]; + matrix[1][2] = z1 * srgb[1][0] + z2 * srgb[1][1] + z3 * srgb[1][2]; + matrix[2][2] = z1 * srgb[2][0] + z2 * srgb[2][1] + z3 * srgb[2][2]; } else { - matrix[0][0] = x1; - matrix[0][1] = x2; - matrix[0][2] = x3; - matrix[1][0] = y1; - matrix[1][1] = y2; - matrix[1][2] = y3; - matrix[2][0] = z1; - matrix[2][1] = z2; - matrix[2][2] = z3; + matrix[0][0] = x1, matrix[1][0] = x2, matrix[2][0] = x3; + matrix[0][1] = y1, matrix[1][1] = y2, matrix[2][1] = y3; + matrix[0][2] = z1, matrix[1][2] = z2, matrix[2][2] = z3; } } |