clutter/color-state: Create colorspace transform from primaries
Colorspace transformation matrices were hardcoded considering only known colorspaces like bt709 or bt2020. Now that a colorspace can be defined from its primaries, allow getting the colorspace transformation matrix from them and drop the hardcoding. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3948>
This commit is contained in:
Joan Torres
Marge Bot
parent
95c9ba514d
commit
a27da4e88f
1 changed files with 234 additions and 67 deletions
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@ -620,33 +620,6 @@ static const char srgb_inv_eotf_source[] =
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" return vec4 (srgb_inv_eotf (color.rgb), color.a);\n"
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"}\n";
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/* Calculated using:
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* numpy.dot(colour.models.RGB_COLOURSPACE_BT2020.matrix_XYZ_to_RGB,
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* colour.models.RGB_COLOURSPACE_BT709.matrix_RGB_to_XYZ)
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*/
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static const float bt709_to_bt2020_matrix[9] = {
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0.6274039f, 0.06909729f, 0.01639144f,
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0.32928304f, 0.9195404f, 0.08801331f,
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0.04331307f, 0.01136232f, 0.89559525f,
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};
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/*
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* Calculated using:
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* numpy.dot(colour.models.RGB_COLOURSPACE_BT709.matrix_XYZ_to_RGB,
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* colour.models.RGB_COLOURSPACE_BT2020.matrix_RGB_to_XYZ)
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*/
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static const float bt2020_to_bt709_matrix[9] = {
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1.660491f, -0.12455047f, -0.01815076f,
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-0.58764114f, 1.1328999f, -0.1005789f,
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-0.07284986f, -0.00834942f, 1.11872966f,
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};
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static const float identity_matrix[9] = {
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1.f, 0.f, 0.f,
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0.f, 1.f, 0.f,
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0.f, 0.f, 1.f,
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};
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typedef struct _TransferFunction
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{
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const char *source;
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@ -804,59 +777,253 @@ chromaticity_equal (float x1,
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G_APPROX_VALUE (y1, y2, 0.000001f);
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}
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static gboolean
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primaries_white_point_equal (ClutterColorState *color_state,
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ClutterColorState *other_color_state)
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{
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const ClutterPrimaries *primaries;
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const ClutterPrimaries *other_primaries;
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primaries = clutter_color_state_get_primaries (color_state);
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other_primaries = clutter_color_state_get_primaries (other_color_state);
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return chromaticity_equal (primaries->w_x, primaries->w_y,
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other_primaries->w_x, other_primaries->w_y);
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}
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static void
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get_white_chromaticity_in_XYZ (float x,
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float y,
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graphene_vec3_t *chromaticity_XYZ)
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{
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if (y == 0.0f)
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{
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/* Avoid a division by 0 */
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y = FLT_EPSILON;
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g_warning ("White point y coordinate is 0, something is probably wrong");
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}
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graphene_vec3_init (chromaticity_XYZ,
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x / y,
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1,
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(1 - x - y) / y);
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}
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/*
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* Get the matrix rgb_to_xyz that makes:
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*
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* color_XYZ = rgb_to_xyz * color_RGB
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*
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* Steps:
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*
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* (1) white_point_XYZ = rgb_to_xyz * white_point_RGB
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*
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* Breaking down rgb_to_xyz: rgb_to_xyz = primaries_mat * coefficients_mat
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*
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* (2) white_point_XYZ = primaries_mat * coefficients_mat * white_point_RGB
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*
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* white_point_RGB is (1, 1, 1) and coefficients_mat is a diagonal matrix:
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* coefficients_vec = coefficients_mat * white_point_RGB
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*
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* (3) white_point_XYZ = primaries_mat * coefficients_vec
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*
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* (4) primaries_mat^-1 * white_point_XYZ = coefficients_vec
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*
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* When coefficients_vec is calculated, coefficients_mat can be composed to
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* finally solve:
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*
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* (5) rgb_to_xyz = primaries_mat * coefficients_mat
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*
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* Notes:
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*
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* white_point_XYZ: xy white point coordinates transformed to XYZ space
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* using the maximum luminance: Y = 1
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*
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* primaries_mat: matrix made from xy chromaticities transformed to xyz
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* considering x + y + z = 1
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*
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* xyz_to_rgb = rgb_to_xyz^-1
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*
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* Reference:
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* https://www.ryanjuckett.com/rgb-color-space-conversion/
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*/
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static gboolean
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get_color_space_trans_matrices (ClutterColorState *color_state,
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graphene_matrix_t *rgb_to_xyz,
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graphene_matrix_t *xyz_to_rgb)
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{
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const ClutterPrimaries *primaries =
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clutter_color_state_get_primaries (color_state);
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graphene_matrix_t coefficients_mat;
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graphene_matrix_t inv_primaries_mat;
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graphene_matrix_t primaries_mat;
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graphene_vec3_t white_point_XYZ;
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graphene_vec3_t coefficients;
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graphene_matrix_init_from_float (
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&primaries_mat,
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(float [16]) {
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primaries->r_x, primaries->r_y, 1 - primaries->r_x - primaries->r_y, 0,
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primaries->g_x, primaries->g_y, 1 - primaries->g_x - primaries->g_y, 0,
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primaries->b_x, primaries->b_y, 1 - primaries->b_x - primaries->b_y, 0,
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0, 0, 0, 1,
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});
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if (!graphene_matrix_inverse (&primaries_mat, &inv_primaries_mat))
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return FALSE;
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get_white_chromaticity_in_XYZ (primaries->w_x, primaries->w_y, &white_point_XYZ);
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graphene_matrix_transform_vec3 (&inv_primaries_mat, &white_point_XYZ, &coefficients);
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graphene_matrix_init_from_float (
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&coefficients_mat,
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(float [16]) {
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graphene_vec3_get_x (&coefficients), 0, 0, 0,
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0, graphene_vec3_get_y (&coefficients), 0, 0,
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0, 0, graphene_vec3_get_z (&coefficients), 0,
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0, 0, 0, 1,
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});
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graphene_matrix_multiply (&coefficients_mat, &primaries_mat, rgb_to_xyz);
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if (!graphene_matrix_inverse (rgb_to_xyz, xyz_to_rgb))
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return FALSE;
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return TRUE;
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}
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/*
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* Get the matrix that converts XYZ chromaticity relative to src_white_point
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* to XYZ chromaticity relative to dst_white_point:
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*
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* dst_XYZ = chromatic_adaptation * src_XYZ
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*
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* Steps:
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*
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* chromatic_adaptation = bradford_mat^-1 * coefficients_mat * bradford_mat
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*
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* coefficients_mat = diag (coefficients)
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*
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* coefficients = dst_white_LMS / src_white_LMS
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*
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* dst_white_LMS = bradford_mat * dst_white_XYZ
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* src_white_LMS = bradford_mat * src_white_XYZ
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*
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* Notes:
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*
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* *_white_XYZ: xy white point coordinates transformed to XYZ space
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* using the maximum luminance: Y = 1
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*
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* Bradford matrix and reference:
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* http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
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*/
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static void
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get_chromatic_adaptation (ClutterColorState *color_state,
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ClutterColorState *target_color_state,
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graphene_matrix_t *chromatic_adaptation)
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{
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const ClutterPrimaries *source_primaries =
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clutter_color_state_get_primaries (color_state);
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const ClutterPrimaries *target_primaries =
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clutter_color_state_get_primaries (target_color_state);
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graphene_matrix_t coefficients_mat;
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graphene_matrix_t bradford_mat, inv_bradford_mat;
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graphene_vec3_t src_white_point_XYZ, dst_white_point_XYZ;
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graphene_vec3_t src_white_point_LMS, dst_white_point_LMS;
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graphene_vec3_t coefficients;
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graphene_matrix_init_from_float (
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&bradford_mat,
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(float [16]) {
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0.8951f, -0.7502f, 0.0389f, 0,
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0.2664f, 1.7135f, -0.0685f, 0,
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-0.1614f, 0.0367f, 1.0296f, 0,
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0, 0, 0, 1,
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});
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graphene_matrix_init_from_float (
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&inv_bradford_mat,
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(float [16]) {
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0.9869929f, 0.4323053f, -0.0085287f, 0,
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-0.1470543f, 0.5183603f, 0.0400428f, 0,
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0.1599627f, 0.0492912f, 0.9684867f, 0,
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0, 0, 0, 1,
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});
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get_white_chromaticity_in_XYZ (source_primaries->w_x, source_primaries->w_y,
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&src_white_point_XYZ);
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get_white_chromaticity_in_XYZ (target_primaries->w_x, target_primaries->w_y,
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&dst_white_point_XYZ);
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graphene_matrix_transform_vec3 (&bradford_mat, &src_white_point_XYZ,
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&src_white_point_LMS);
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graphene_matrix_transform_vec3 (&bradford_mat, &dst_white_point_XYZ,
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&dst_white_point_LMS);
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graphene_vec3_divide (&dst_white_point_LMS, &src_white_point_LMS,
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&coefficients);
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graphene_matrix_init_from_float (
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&coefficients_mat,
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(float [16]) {
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graphene_vec3_get_x (&coefficients), 0, 0, 0,
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0, graphene_vec3_get_y (&coefficients), 0, 0,
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0, 0, graphene_vec3_get_z (&coefficients), 0,
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0, 0, 0, 1,
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});
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graphene_matrix_multiply (&bradford_mat, &coefficients_mat,
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chromatic_adaptation);
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graphene_matrix_multiply (chromatic_adaptation, &inv_bradford_mat,
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chromatic_adaptation);
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}
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static void
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get_color_space_mapping_matrix (ClutterColorState *color_state,
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ClutterColorState *target_color_state,
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float out_color_space_mapping[9])
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{
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ClutterColorStatePrivate *priv =
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clutter_color_state_get_instance_private (color_state);
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ClutterColorStatePrivate *target_priv =
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clutter_color_state_get_instance_private (target_color_state);
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graphene_matrix_t matrix;
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graphene_matrix_t src_rgb_to_xyz, src_xyz_to_rgb;
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graphene_matrix_t target_rgb_to_xyz, target_xyz_to_rgb;
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graphene_matrix_t chromatic_adaptation;
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switch (priv->colorspace)
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if (!get_color_space_trans_matrices (color_state,
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&src_rgb_to_xyz,
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&src_xyz_to_rgb) ||
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!get_color_space_trans_matrices (target_color_state,
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&target_rgb_to_xyz,
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&target_xyz_to_rgb))
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{
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case CLUTTER_COLORSPACE_SRGB:
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case CLUTTER_COLORSPACE_DEFAULT:
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switch (target_priv->colorspace)
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graphene_matrix_init_identity (&matrix);
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}
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else
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{
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if (!primaries_white_point_equal (color_state, target_color_state))
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{
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case CLUTTER_COLORSPACE_BT2020:
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memcpy (out_color_space_mapping,
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bt709_to_bt2020_matrix,
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sizeof (bt709_to_bt2020_matrix));
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return;
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case CLUTTER_COLORSPACE_SRGB:
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case CLUTTER_COLORSPACE_DEFAULT:
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memcpy (out_color_space_mapping,
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identity_matrix,
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sizeof (identity_matrix));
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return;
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get_chromatic_adaptation (color_state, target_color_state,
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&chromatic_adaptation);
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graphene_matrix_multiply (&src_rgb_to_xyz, &chromatic_adaptation,
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&matrix);
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graphene_matrix_multiply (&matrix, &target_xyz_to_rgb,
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&matrix);
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}
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break;
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case CLUTTER_COLORSPACE_BT2020:
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switch (target_priv->colorspace)
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else
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{
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case CLUTTER_COLORSPACE_BT2020:
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memcpy (out_color_space_mapping,
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identity_matrix,
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sizeof (identity_matrix));
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return;
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case CLUTTER_COLORSPACE_SRGB:
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case CLUTTER_COLORSPACE_DEFAULT:
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memcpy (out_color_space_mapping,
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bt2020_to_bt709_matrix,
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sizeof (bt2020_to_bt709_matrix));
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return;
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graphene_matrix_multiply (&src_rgb_to_xyz, &target_xyz_to_rgb, &matrix);
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}
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break;
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}
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g_warning ("Unhandled colorspace %s",
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clutter_colorspace_to_string (priv->colorspace));
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memcpy (out_color_space_mapping,
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identity_matrix,
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sizeof (identity_matrix));
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out_color_space_mapping[0] = graphene_matrix_get_value (&matrix, 0, 0);
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out_color_space_mapping[1] = graphene_matrix_get_value (&matrix, 0, 1);
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out_color_space_mapping[2] = graphene_matrix_get_value (&matrix, 0, 2);
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out_color_space_mapping[3] = graphene_matrix_get_value (&matrix, 1, 0);
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out_color_space_mapping[4] = graphene_matrix_get_value (&matrix, 1, 1);
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out_color_space_mapping[5] = graphene_matrix_get_value (&matrix, 1, 2);
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out_color_space_mapping[6] = graphene_matrix_get_value (&matrix, 2, 0);
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out_color_space_mapping[7] = graphene_matrix_get_value (&matrix, 2, 1);
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out_color_space_mapping[8] = graphene_matrix_get_value (&matrix, 2, 2);
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}
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static CoglSnippet *
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