tests: replace mat2XYZ
The primaries and the white point are the fundamental definition of the
color spaces in these tests. Instead of hard-coding mat2XYZ, use
LittleCMS to derive the result from the fundamental definition.
This removes derived hard-coded constants, which is a benefit in itself.
How these constants were originally produced was not mentioned in
0c5860fafb
but I was able to reproduce
them with python3:
import colour
import numpy as np
x = colour.RGB_COLOURSPACES['sRGB']
w_d50 = np.array([0.34567, 0.35850])
print(x.chromatically_adapt(w_d50, 'D50', 'Bradford'))
It's identical to 3-4 decimals of the hardcoded values, and also for
Adobe RGB. I printed the LittleCMS generated values as well, and they
are the same as with python up to roughly 4 decimals.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
This commit is contained in:
parent
7d38e044dd
commit
94ccce4e38
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@ -59,9 +59,6 @@ const struct lcms_pipeline pipeline_sRGB = {
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.mat = LCMSMAT3(1.0, 0.0, 0.0,
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0.0, 1.0, 0.0,
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0.0, 0.0, 1.0),
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.mat2XYZ = LCMSMAT3(0.436037, 0.385124, 0.143039,
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0.222482, 0.716913, 0.060605,
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0.013922, 0.097078, 0.713899),
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.post_fn = TRANSFER_FN_SRGB_EOTF_INVERSE
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};
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@ -76,9 +73,6 @@ const struct lcms_pipeline pipeline_adobeRGB = {
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.mat = LCMSMAT3( 0.715127, 0.284868, 0.000005,
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0.000001, 0.999995, 0.000004,
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-0.000003, 0.041155, 0.958848),
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.mat2XYZ = LCMSMAT3(0.609740, 0.205279, 0.149181,
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0.311111, 0.625681, 0.063208,
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0.019469, 0.060879, 0.744552),
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.post_fn = TRANSFER_FN_ADOBE_RGB_EOTF_INVERSE
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};
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@ -61,9 +61,6 @@ const struct lcms_pipeline pipeline_sRGB = {
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.mat = LCMSMAT3(1.0, 0.0, 0.0,
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0.0, 1.0, 0.0,
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0.0, 0.0, 1.0),
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.mat2XYZ = LCMSMAT3(0.436037, 0.385124, 0.143039,
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0.222482, 0.716913, 0.060605,
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0.013922, 0.097078, 0.713899),
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.post_fn = TRANSFER_FN_SRGB_EOTF_INVERSE
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};
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@ -32,11 +32,12 @@
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#include <assert.h>
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#include <stdlib.h>
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#include <libweston/matrix.h>
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#include "shared/helpers.h"
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#include "color_util.h"
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#include "lcms_util.h"
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static cmsCIExyY wp_d65 = { 0.31271, 0.32902, 1.0 };
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static const cmsCIExyY wp_d65 = { 0.31271, 0.32902, 1.0 };
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/*
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* MPE tone curves can only use LittleCMS parametric curve types 6-8 and not
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@ -280,32 +281,33 @@ roundtrip_verification(cmsPipeline *DToB, cmsPipeline *BToD, float tolerance)
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assert(stat.two_norm.max < tolerance);
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}
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struct transform_sampler_context {
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cmsHTRANSFORM t;
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};
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static cmsInt32Number
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sampler_matrix(const float src[], float dst[], void *cargo)
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transform_sampler(const float src[], float dst[], void *cargo)
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{
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const struct lcmsMAT3 *mat = cargo;
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struct color_float in = { .r = src[0], .g = src[1], .b = src[2] };
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struct color_float cf;
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unsigned i;
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const struct transform_sampler_context *tsc = cargo;
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cf = color_float_apply_matrix(mat, in);
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for (i = 0; i < COLOR_CHAN_NUM; i++)
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dst[i] = cf.rgb[i];
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cmsDoTransform(tsc->t, src, dst, 1);
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return 1;
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}
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static cmsStage *
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create_cLUT_from_matrix(cmsContext context_id, const struct lcmsMAT3 *mat,
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int dim_size)
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create_cLUT_from_transform(cmsContext context_id, const cmsHTRANSFORM t,
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int dim_size)
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{
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struct transform_sampler_context tsc;
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cmsStage *cLUT_stage;
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assert(dim_size);
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tsc.t = t;
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cLUT_stage = cmsStageAllocCLutFloat(context_id, dim_size, 3, 3, NULL);
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cmsStageSampleCLutFloat(cLUT_stage, sampler_matrix, (void *)mat, 0);
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cmsStageSampleCLutFloat(cLUT_stage, transform_sampler, &tsc, 0);
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return cLUT_stage;
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}
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@ -341,9 +343,41 @@ build_lcms_clut_profile_output(cmsContext context_id,
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cmsStage *stage;
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cmsStage *stage_inv_eotf;
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cmsStage *stage_eotf;
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struct lcmsMAT3 mat2XYZ_inv;
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cmsToneCurve *identity_curves[3];
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cmsHPROFILE linear_device;
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cmsHPROFILE pcs;
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cmsHTRANSFORM linear_device_to_pcs;
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cmsHTRANSFORM pcs_to_linear_device;
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lcmsMAT3_invert(&mat2XYZ_inv, &pipeline->mat2XYZ);
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identity_curves[0] = identity_curves[1] = identity_curves[2] =
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cmsBuildGamma(context_id, 1.0);
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linear_device = cmsCreateRGBProfileTHR(context_id, &wp_d65,
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&pipeline->prim_output,
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identity_curves);
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assert(cmsIsMatrixShaper(linear_device));
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cmsFreeToneCurve(identity_curves[0]);
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pcs = cmsCreateXYZProfileTHR(context_id);
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/*
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* Since linear_device is a matrix-shaper profile, all rendering intents
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* share the same device<->PCS transformations. We only need to pick
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* an arbitrary rendering intent that allows to turn BPC both on and off.
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*/
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linear_device_to_pcs = cmsCreateTransformTHR(context_id,
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linear_device, TYPE_RGB_FLT,
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pcs, TYPE_XYZ_FLT,
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INTENT_RELATIVE_COLORIMETRIC,
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cmsFLAGS_NOOPTIMIZE);
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pcs_to_linear_device = cmsCreateTransformTHR(context_id,
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pcs, TYPE_XYZ_FLT,
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linear_device, TYPE_RGB_FLT,
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INTENT_RELATIVE_COLORIMETRIC,
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cmsFLAGS_NOOPTIMIZE);
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cmsCloseProfile(linear_device);
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cmsCloseProfile(pcs);
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hRGB = cmsCreateProfilePlaceholder(context_id);
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cmsSetProfileVersion(hRGB, 4.3);
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@ -360,7 +394,8 @@ build_lcms_clut_profile_output(cmsContext context_id,
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*/
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BToD0 = cmsPipelineAlloc(context_id, 3, 3);
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stage = create_cLUT_from_matrix(context_id, &mat2XYZ_inv, clut_dim_size);
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stage = create_cLUT_from_transform(context_id, pcs_to_linear_device,
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clut_dim_size);
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cmsPipelineInsertStage(BToD0, cmsAT_END, stage);
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cmsPipelineInsertStage(BToD0, cmsAT_END, cmsStageDup(stage_inv_eotf));
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@ -375,7 +410,8 @@ build_lcms_clut_profile_output(cmsContext context_id,
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DToB0 = cmsPipelineAlloc(context_id, 3, 3);
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cmsPipelineInsertStage(DToB0, cmsAT_END, cmsStageDup(stage_eotf));
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stage = create_cLUT_from_matrix(context_id, &pipeline->mat2XYZ, clut_dim_size);
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stage = create_cLUT_from_transform(context_id, linear_device_to_pcs,
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clut_dim_size);
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cmsPipelineInsertStage(DToB0, cmsAT_END, stage);
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cmsWriteTag(hRGB, cmsSigDToB0Tag, DToB0);
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@ -392,6 +428,9 @@ build_lcms_clut_profile_output(cmsContext context_id,
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cmsStageFree(stage_eotf);
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cmsStageFree(stage_inv_eotf);
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cmsDeleteTransform(linear_device_to_pcs);
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cmsDeleteTransform(pcs_to_linear_device);
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return hRGB;
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}
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@ -36,6 +36,7 @@ struct lcms_pipeline {
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const char *color_space;
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/**
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* Chromaticities for output profile
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* White point is assumed to be D65.
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*/
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cmsCIExyYTRIPLE prim_output;
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/**
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* Transform matrix from sRGB to target chromaticities in prim_output
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*/
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struct lcmsMAT3 mat;
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/**
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* matrix from prim_output to XYZ, for example matrix conversion
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* sRGB->XYZ, adobeRGB->XYZ, bt2020->XYZ
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*/
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struct lcmsMAT3 mat2XYZ;
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/**
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* tone curve enum
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*/
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