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tests: add lcms-util with MPE curves

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This adds a new test helper library that depends on LittleCMS 2.

For starters, the library implements conversion from enum transfer_fn to
ICC multiProcessingElements compatible LittleCMS curve object.

That conversion allows encoding transfer funtions in ICC files and
LittleCMS pipelines with full float32 precision instead of forcing a
conversion to a 1D LUT which for power-type curves is surprisingly
imprecise.

This also adds CI tests to make sure the conversion matches our
hand-coded transfer functions.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
This commit is contained in:
Pekka Paalanen 2022-05-20 14:07:04 +03:00 committed by Pekka Paalanen
parent 0225453fb1
commit 44c3079567
6 changed files with 345 additions and 2 deletions
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2
tests/color_util.c
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@ -212,7 +212,7 @@ Power2_4_EOTF_inv(float o)
return pow(o, 1./2.4);
}
static float
float
apply_tone_curve(enum transfer_fn fn, float r)
{
float ret = 0;

3
tests/color_util.h
View File

@ -97,6 +97,9 @@ a8r8g8b8_to_float(uint32_t v);
bool
find_tone_curve_type(enum transfer_fn fn, int *type, double params[5]);
float
apply_tone_curve(enum transfer_fn fn, float r);
void
process_pixel_using_pipeline(enum transfer_fn pre_curve,
const struct lcmsMAT3 *mat,

85
tests/lcms-util-test.c Normal file
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@ -0,0 +1,85 @@
/*
* Copyright 2022 Collabora, Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "config.h"
#include <math.h>
#include <lcms2.h>
#include "weston-test-client-helper.h"
#include "color_util.h"
#include "lcms_util.h"
static void
compare_pipeline_to_transfer_fn(cmsPipeline *pipeline, enum transfer_fn fn,
struct scalar_stat *stat)
{
const unsigned N = 100000;
unsigned i;
for (i = 0; i < N; i++) {
float x = (double)i / N;
float ref = apply_tone_curve(fn, x);
float y;
cmsPipelineEvalFloat(&x, &y, pipeline);
scalar_stat_update(stat, y - ref, &(struct color_float){ .r = x });
}
}
static const enum transfer_fn build_MPE_curves_test_set[] = {
TRANSFER_FN_SRGB_EOTF,
TRANSFER_FN_SRGB_EOTF_INVERSE,
TRANSFER_FN_ADOBE_RGB_EOTF,
TRANSFER_FN_ADOBE_RGB_EOTF_INVERSE,
TRANSFER_FN_POWER2_4_EOTF,
TRANSFER_FN_POWER2_4_EOTF_INVERSE,
};
TEST_P(build_MPE_curves, build_MPE_curves_test_set)
{
const enum transfer_fn *fn = data;
const cmsContext ctx = 0;
cmsToneCurve *curve;
cmsStage *stage;
cmsPipeline *pipeline;
struct scalar_stat stat = {};
curve = build_MPE_curve(ctx, *fn);
stage = cmsStageAllocToneCurves(ctx, 1, &curve);
cmsFreeToneCurve(curve);
pipeline = cmsPipelineAlloc(ctx, 1, 1);
cmsPipelineInsertStage(pipeline, cmsAT_END, stage);
compare_pipeline_to_transfer_fn(pipeline, *fn, &stat);
testlog("Transfer function %s as a segmented curve element, error:\n",
transfer_fn_name(*fn));
scalar_stat_print_float(&stat);
assert(fabs(stat.max) < 1e-7);
assert(fabs(stat.min) < 1e-7);
cmsPipelineFree(pipeline);
}

200
tests/lcms_util.c Normal file
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@ -0,0 +1,200 @@
/*
* Copyright 2022 Collabora, Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "config.h"
#include <math.h>
#include <lcms2.h>
#include <assert.h>
#include "shared/helpers.h"
#include "color_util.h"
#include "lcms_util.h"
/*
* MPE tone curves can only use LittleCMS parametric curve types 6-8 and not
* inverses.
* type 6: Y = (aX + b)^g + c; params [g, a, b, c]
* type 7: Y = a log(bX^g + c) + d; params [g, a, b, c, d]
* type 8: Y = a b^(cX + d) + e; params [a, b, c, d, e]
* Additionally, type 0 is sampled segment.
*
* cmsCurveSegment.x1 is the breakpoint stored in ICC files, except for the
* last segment. First segment always begins at -Inf, and last segment always
* ends at Inf.
*/
static cmsToneCurve *
build_MPE_curve_sRGB(cmsContext ctx)
{
cmsCurveSegment segments[] = {
{
/* Constant zero segment */
.x0 = -HUGE_VAL,
.x1 = 0.0,
.Type = 6,
.Params = { 1.0, 0.0, 0.0, 0.0 },
},
{
/* Linear segment y = x / 12.92 */
.x0 = 0.0,
.x1 = 0.04045,
.Type = 0,
.nGridPoints = 2,
.SampledPoints = (float[]){ 0.0, 0.04045 / 12.92 },
},
{
/* Power segment y = ((x + 0.055) / 1.055)^2.4
* which is translated to
* y = (1/1.055 * x + 0.055 / 1.055)^2.4 + 0.0
*/
.x0 = 0.04045,
.x1 = 1.0,
.Type = 6,
.Params = { 2.4, 1.0 / 1.055, 0.055 / 1.055, 0.0 },
},
{
/* Constant one segment */
.x0 = 1.0,
.x1 = HUGE_VAL,
.Type = 6,
.Params = { 1.0, 0.0, 0.0, 1.0 },
}
};
return cmsBuildSegmentedToneCurve(ctx, ARRAY_LENGTH(segments), segments);
}
static cmsToneCurve *
build_MPE_curve_sRGB_inv(cmsContext ctx)
{
cmsCurveSegment segments[] = {
{
/* Constant zero segment */
.x0 = -HUGE_VAL,
.x1 = 0.0,
.Type = 6,
.Params = { 1.0, 0.0, 0.0, 0.0 },
},
{
/* Linear segment y = x * 12.92 */
.x0 = 0.0,
.x1 = 0.04045 / 12.92,
.Type = 0,
.nGridPoints = 2,
.SampledPoints = (float[]){ 0.0, 0.04045 },
},
{
/* Power segment y = 1.055 * x^(1/2.4) - 0.055
* which is translated to
* y = (1.055^2.4 * x + 0.0)^(1/2.4) - 0.055
*/
.x0 = 0.04045 / 12.92,
.x1 = 1.0,
.Type = 6,
.Params = { 1.0 / 2.4, pow(1.055, 2.4), 0.0, -0.055 },
},
{
/* Constant one segment */
.x0 = 1.0,
.x1 = HUGE_VAL,
.Type = 6,
.Params = { 1.0, 0.0, 0.0, 1.0 },
}
};
return cmsBuildSegmentedToneCurve(ctx, ARRAY_LENGTH(segments), segments);
}
static cmsToneCurve *
build_MPE_curve_power(cmsContext ctx, double exponent)
{
cmsCurveSegment segments[] = {
{
/* Constant zero segment */
.x0 = -HUGE_VAL,
.x1 = 0.0,
.Type = 6,
.Params = { 1.0, 0.0, 0.0, 0.0 },
},
{
/* Power segment y = x^exponent
* which is translated to
* y = (1.0 * x + 0.0)^exponent + 0.0
*/
.x0 = 0.0,
.x1 = 1.0,
.Type = 6,
.Params = { exponent, 1.0, 0.0, 0.0 },
},
{
/* Constant one segment */
.x0 = 1.0,
.x1 = HUGE_VAL,
.Type = 6,
.Params = { 1.0, 0.0, 0.0, 1.0 },
}
};
return cmsBuildSegmentedToneCurve(ctx, ARRAY_LENGTH(segments), segments);
}
cmsToneCurve *
build_MPE_curve(cmsContext ctx, enum transfer_fn fn)
{
switch (fn) {
case TRANSFER_FN_ADOBE_RGB_EOTF:
return build_MPE_curve_power(ctx, 563.0 / 256.0);
case TRANSFER_FN_ADOBE_RGB_EOTF_INVERSE:
return build_MPE_curve_power(ctx, 256.0 / 563.0);
case TRANSFER_FN_POWER2_4_EOTF:
return build_MPE_curve_power(ctx, 2.4);
case TRANSFER_FN_POWER2_4_EOTF_INVERSE:
return build_MPE_curve_power(ctx, 1.0 / 2.4);
case TRANSFER_FN_SRGB_EOTF:
return build_MPE_curve_sRGB(ctx);
case TRANSFER_FN_SRGB_EOTF_INVERSE:
return build_MPE_curve_sRGB_inv(ctx);
default:
assert(0 && "unimplemented MPE curve");
}
return NULL;
}
cmsStage *
build_MPE_curve_stage(cmsContext context_id, enum transfer_fn fn)
{
cmsToneCurve *c;
cmsStage *stage;
c = build_MPE_curve(context_id, fn);
stage = cmsStageAllocToneCurves(context_id, 3,
(cmsToneCurve *[3]){ c, c, c });
assert(stage);
cmsFreeToneCurve(c);
return stage;
}

36
tests/lcms_util.h Normal file
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@ -0,0 +1,36 @@
/*
* Copyright 2022 Collabora, Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#pragma once
#include <lcms2.h>
#include "color_util.h"
cmsToneCurve *
build_MPE_curve(cmsContext ctx, enum transfer_fn fn);
cmsStage *
build_MPE_curve_stage(cmsContext context_id, enum transfer_fn fn);

21
tests/meson.build
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@ -60,6 +60,21 @@ dep_test_client = declare_dependency(
]
)
lib_lcms_util = static_library(
'lib_lcms_util',
[ 'lcms_util.c' ],
include_directories: common_inc,
dependencies: [
dep_lcms2, dep_libm
],
build_by_default: false,
install: false,
)
dep_lcms_util = declare_dependency(
link_with: lib_lcms_util,
dependencies: [ dep_lcms2 ]
)
exe_plugin_test = shared_library(
'test-plugin',
'weston-test.c',
@ -243,11 +258,15 @@ if get_option('color-management-lcms')
error('color-management-lcms tests require lcms2 which was not found. Or, you can use \'-Dcolor-management-lcms=false\'.')
endif
tests += [
{ 'name': 'color-metadata-parsing' },
{
'name': 'color-shaper-matrix',
'dep_objs': [ dep_libm, dep_lcms2 ]
},
{ 'name': 'color-metadata-parsing' },
{
'name': 'lcms-util',
'dep_objs': [ dep_lcms_util ]
},
]
endif