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color-lcms: use weston_mat4f for matrix stages

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This makes multiply_matrix_stages() handle offset vectors correctly, but
they will not apprear here yet, because
is_matrix_stage_with_zero_offset() forbids merging such matrices.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
This commit is contained in:
Pekka Paalanen 2025-03-25 16:07:16 +02:00
parent d3561621e3
commit b872c71820
1 changed files with 38 additions and 52 deletions
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90
libweston/color-lcms/color-transform.c
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@ -28,6 +28,7 @@
#include <assert.h>
#include <libweston/libweston.h>
#include <libweston/linalg.h>
#include <lcms2_plugin.h>
#include "color.h"
@ -176,56 +177,34 @@ cmlcms_color_transform_destroy(struct cmlcms_color_transform *xform)
free(xform);
}
/**
* Matrix infinity norm
*
* http://www.netlib.org/lapack/lug/node75.html
*/
static double
matrix_inf_norm(const cmsMAT3 *mat)
{
unsigned row;
double infnorm = -1.0;
for (row = 0; row < 3; row++) {
unsigned col;
double sum = 0.0;
for (col = 0; col < 3; col++)
sum += fabs(mat->v[row].n[col]);
if (infnorm < sum)
infnorm = sum;
}
return infnorm;
}
/*
* The method of testing for identity matrix is from
* https://gitlab.freedesktop.org/pq/fourbyfour/-/blob/master/README.d/precision_testing.md#inversion-error
*/
static bool
matrix_is_identity(const cmsMAT3 *mat, int bits_precision)
matrix_is_identity(struct weston_mat4f M, int bits_precision)
{
cmsMAT3 tmp = *mat;
double err;
int i;
/* subtract identity matrix */
for (i = 0; i < 3; i++)
tmp.v[i].n[i] -= 1.0;
err = matrix_inf_norm(&tmp);
return -log2(err) >= bits_precision;
M = weston_m4f_sub_m4f(M, WESTON_MAT4F_IDENTITY);
return -log2(weston_m4f_inf_norm(M)) >= bits_precision;
}
static const cmsMAT3 *
stage_matrix(const _cmsStageMatrixData *smd)
static struct weston_mat4f
stage_matrix_get_mat4(const _cmsStageMatrixData *smd)
{
/* Both are row-major. */
return (const cmsMAT3 *)smd->Double;
const double *p = smd->Offset;
const double *d = smd->Double;
struct weston_vec3f t = WESTON_VEC3F_ZERO;
struct weston_mat3f A = WESTON_MAT3F(
/* smd is row-major. */
d[0], d[1], d[2],
d[3], d[4], d[5],
d[6], d[7], d[8]
);
if (p)
t = WESTON_VEC3F(p[0], p[1], p[2]);
return weston_m4f_from_m3f_v3f(A, t);
}
static bool
@ -253,30 +232,37 @@ is_matrix_stage_with_zero_offset(const cmsStage *stage)
static bool
is_identity_matrix_stage(const cmsStage *stage)
{
_cmsStageMatrixData *data;
const _cmsStageMatrixData *data;
struct weston_mat4f M;
if (!is_matrix_stage_with_zero_offset(stage))
return false;
data = cmsStageData(stage);
return matrix_is_identity(stage_matrix(data),
MATRIX_PRECISION_BITS);
M = stage_matrix_get_mat4(data);
return matrix_is_identity(M, MATRIX_PRECISION_BITS);
}
/* Returns the matrix (next * prev). */
static cmsStage *
multiply_matrix_stages(cmsContext context_id, cmsStage *next, cmsStage *prev)
{
_cmsStageMatrixData *prev_, *next_;
cmsMAT3 res;
struct weston_mat4f M_prev = stage_matrix_get_mat4(cmsStageData(prev));
struct weston_mat4f M_next = stage_matrix_get_mat4(cmsStageData(next));
struct weston_mat4f R = weston_m4f_mul_m4f(M_next, M_prev);
double A[9] = {
/* row-major */
R.col[0].el[0], R.col[1].el[0], R.col[2].el[0],
R.col[0].el[1], R.col[1].el[1], R.col[2].el[1],
R.col[0].el[2], R.col[1].el[2], R.col[2].el[2]
};
double t[3] = {
R.col[3].el[0], R.col[3].el[1], R.col[3].el[2]
};
cmsStage *ret;
prev_ = cmsStageData(prev);
next_ = cmsStageData(next);
_cmsMAT3per(&res, stage_matrix(next_), stage_matrix(prev_));
ret = cmsStageAllocMatrix(context_id, 3, 3,
(const cmsFloat64Number*)&res, NULL);
ret = cmsStageAllocMatrix(context_id, 3, 3, A, t);
abort_oom_if_null(ret);
return ret;
}