gtk/testsuite/gdk/colorstate-internal.c

#include <gdk/gdk.h>
#include "gdkcolorstateprivate.h"
#include "gdkcolorprivate.h"
#include <math.h>

#include "gdkcolordefs.h"

typedef float (* TransferFunc) (float v);

typedef struct
{
  const char *name;
  TransferFunc oetf;
  TransferFunc eotf;
  float o_range[2];
  float e_range[2];
} TransferTest;

TransferTest transfers[] = {
  { "srgb",    srgb_oetf,    srgb_eotf,    { 0, 1 }, { 0, 1} },
  { "pq",      pq_oetf,      pq_eotf,      { 0, 49.2610855 }, { 0, 1 } },
  { "bt709",   bt709_oetf,   bt709_eotf,   { 0, 1 }, { 0, 1 } },
  { "hlg",     hlg_oetf,     hlg_eotf,     { 0, 1}, { 0, 1} },
  { "gamma22", gamma22_oetf, gamma22_eotf, { 0, 1 }, { 0, 1 } },
  { "gamma28", gamma28_oetf, gamma28_eotf, { 0, 1 }, { 0, 1 } },
  { "oklab",   to_oklab_nl,  from_oklab_nl,{ 0, 1 }, { 0, 1 } },
};

#define LERP(t, a, b) ((a) + (t) * ((b) - (a)))

#define ASSERT_IN_RANGE(v, a, b, epsilon) \
  g_assert_cmpfloat_with_epsilon (MIN(v,a), a, epsilon); \
  g_assert_cmpfloat_with_epsilon (MAX(v,b), b, epsilon); \

static void
test_transfer (gconstpointer data)
{
  TransferTest *transfer = (TransferTest *) data;
  float v, v1, v2;

  for (int i = 0; i < 1001; i++)
    {
      v = LERP (i/1000.0, transfer->e_range[0], transfer->e_range[1]);

      v1 = transfer->eotf (v);

      ASSERT_IN_RANGE (v1, transfer->o_range[0], transfer->o_range[1], 0.0001);

      v2 = transfer->oetf (v1);

      g_assert_cmpfloat_with_epsilon (v, v2, 0.05);
    }

  for (int i = 0; i < 1001; i++)
    {
      v = LERP (i/1000.0, transfer->o_range[0], transfer->o_range[1]);

      v1 = transfer->oetf (v);

      ASSERT_IN_RANGE (v1, transfer->e_range[0], transfer->e_range[1], 0.0001);

      v2 = transfer->eotf (v1);

      g_assert_cmpfloat_with_epsilon (v, v2, 0.05);
    }
}

static void
test_transfer_symmetry (gconstpointer data)
{
  TransferTest *transfer = (TransferTest *) data;
  float v, v1, v2;

  for (int i = 0; i < 11; i++)
    {
      v = LERP (i/10.0, transfer->e_range[0], transfer->e_range[1]);

      v1 = transfer->eotf (v);
      v2 = -transfer->eotf (-v);

      g_assert_cmpfloat_with_epsilon (v1, v2, 0.05);
   }

  for (int i = 0; i < 11; i++)
    {
      v = LERP (i/10.0, transfer->o_range[0], transfer->o_range[1]);

      v1 = transfer->oetf (v);
      v2 = -transfer->oetf (-v);

      g_assert_cmpfloat_with_epsilon (v1, v2, 0.05);
    }
}
typedef struct
{
  const char *name;
  const float *to_xyz;
  const float *from_xyz;
} MatrixTest;
static MatrixTest matrices[] = {
  { "srgb", srgb_to_xyz, xyz_to_srgb },
  { "rec2020", rec2020_to_xyz, xyz_to_rec2020 },
  { "pal", pal_to_xyz, xyz_to_pal },
  { "ntsc", ntsc_to_xyz, xyz_to_ntsc },
  { "p3", p3_to_xyz, xyz_to_p3 },
  { "srgb<>rec2020", rec2020_to_srgb, srgb_to_rec2020 },
  { "oklab<>lms", oklab_to_lms, lms_to_oklab },
  { "lms<>srgb", lms_to_srgb, srgb_to_lms },
};

#define IDX(i,j) 3*i+j
static inline void
multiply (float       res[9],
          const float m1[9],
          const float m2[9])
{
  for (int i = 0; i < 3; i++)
    for (int j = 0; j < 3; j++)
      res[IDX(i,j)] =   m1[IDX(i,0)] * m2[IDX(0,j)]
                      + m1[IDX(i,1)] * m2[IDX(1,j)]
                      + m1[IDX(i,2)] * m2[IDX(2,j)];
}

static inline void
difference (float       res[9],
            const float m1[9],
            const float m2[9])
{
  for (int i = 0; i < 9; i++)
    res[i] = m1[i] - m2[i];
}

static float
norm (const float m[9])
{
  float sum = 0;

  for (int i = 0; i < 9; i++)
    sum += m[i] * m[i];

  return sqrtf (sum);
}

static void
print_matrix (const float m[9])
{
  g_print ("%f %f %f\n%f %f %f\n%f %f %f\n",
           m[0], m[1], m[2],
           m[3], m[4], m[5],
           m[6], m[7], m[8]);
}

static void
test_matrix (gconstpointer data)
{
  MatrixTest *matrix = (MatrixTest *) data;
  float res[9];
  float res2[9];

  multiply (res, matrix->to_xyz, matrix->from_xyz);

  if (g_test_verbose ())
    print_matrix (res);

  difference (res2, res, identity);

  if (g_test_verbose ())
    g_print ("distance: %f\n", norm (res2));

  g_assert_cmpfloat_with_epsilon (norm (res2), 0, 0.001);
}

static void
test_srgb_to_rec2020 (void)
{
  float m[9], res[9];

  multiply (m, xyz_to_rec2020, srgb_to_xyz);
  difference (res, m, srgb_to_rec2020);

  g_assert_cmpfloat_with_epsilon (norm (res), 0, 0.001);
}

static void
test_rec2020_to_srgb (void)
{
  float m[9], res[9];

  multiply (m, xyz_to_srgb, rec2020_to_xyz);
  difference (res, m, rec2020_to_srgb);

  g_assert_cmpfloat_with_epsilon (norm (res), 0, 0.001);
}

/* Verify that this color is different enough in srgb-linear and srgb
 * to be detected.
 */
static void
test_color_mislabel (void)
{
  GdkColor color;
  GdkColor color1;
  GdkColor color2;
  guint red1, red2;

  gdk_color_init (&color, gdk_color_state_get_srgb_linear (), (float[]) { 0.604, 0, 0, 1 });
  gdk_color_convert (&color1, gdk_color_state_get_srgb (), &color);
  gdk_color_init (&color2, gdk_color_state_get_srgb (), (float[]) { 0.604, 0, 0, 1 });

  g_assert_true (!gdk_color_equal (&color1, &color2));

  red1 = round (color1.red * 255.0);
  red2 = round (color2.red * 255.0);

  g_assert_true (red1 != red2);
}

int
main (int argc, char *argv[])
{
  (g_test_init) (&argc, &argv, NULL);

  for (guint i = 0; i < G_N_ELEMENTS (transfers); i++)
    {
      TransferTest *test = &transfers[i];
      char *path = g_strdup_printf ("/colorstate/transfer/%s", test->name);
      g_test_add_data_func (path, test, test_transfer);
      g_free (path);
    }

  for (guint i = 0; i < G_N_ELEMENTS (transfers); i++)
    {
      TransferTest *test = &transfers[i];
      char *path = g_strdup_printf ("/colorstate/transfer-symmetry/%s", test->name);
      g_test_add_data_func (path, test, test_transfer_symmetry);
      g_free (path);
    }

  for (guint i = 0; i < G_N_ELEMENTS (matrices); i++)
    {
      MatrixTest *test = &matrices[i];
      char *path = g_strdup_printf ("/colorstate/matrix/%s", test->name);
      g_test_add_data_func (path, test, test_matrix);
      g_free (path);
    }

  g_test_add_func ("/colorstate/matrix/srgb_to_rec2020", test_srgb_to_rec2020);
  g_test_add_func ("/colorstate/matrix/rec2020_to_srgb", test_rec2020_to_srgb);
  g_test_add_func ("/color/mislabel", test_color_mislabel);

  return g_test_run ();
}