/*

 * HEIF codec.

 * Copyright (c) 2020 struktur AG, Dirk Farin <farin@struktur.de>

 *

 * This file is part of libheif.

 *

 * libheif is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation, either version 3 of

 * the License, or (at your option) any later version.

 *

 * libheif is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with libheif.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "nclx.h"

heif::primaries::primaries(float gx, float gy, float bx, float by, float rx, float ry, float wx, float wy)

{

  defined = true;

  redX = rx;

  redY = ry;

  greenX = gx;

  greenY = gy;

  blueX = bx;

  blueY = by;

  whiteX = wx;

  whiteY = wy;

}

heif::primaries heif::get_colour_primaries(uint16_t primaries_idx)

{

  switch (primaries_idx) {

    case 1:

      return {0.300f, 0.600f, 0.150f, 0.060f, 0.640f, 0.330f, 0.3127f, 0.3290f};

    case 4:

      return {0.21f, 0.71f, 0.14f, 0.08f, 0.67f, 0.33f, 0.310f, 0.316f};

    case 5:

      return {0.29f, 0.60f, 0.15f, 0.06f, 0.64f, 0.33f, 0.3127f, 0.3290f};

    case 6:

    case 7:

      return {0.310f, 0.595f, 0.155f, 0.070f, 0.630f, 0.340f, 0.3127f, 0.3290f};

    case 8:

      return {0.243f, 0.692f, 0.145f, 0.049f, 0.681f, 0.319f, 0.310f, 0.316f};

    case 9:

      return {0.170f, 0.797f, 0.131f, 0.046f, 0.708f, 0.292f, 0.3127f, 0.3290f};

    case 10:

      return {0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.333333f, 0.33333f};

    case 11:

      return {0.265f, 0.690f, 0.150f, 0.060f, 0.680f, 0.320f, 0.314f, 0.351f};

    case 12:

      return {0.265f, 0.690f, 0.150f, 0.060f, 0.680f, 0.320f, 0.3127f, 0.3290f};

    case 22:

      return {0.295f, 0.605f, 0.155f, 0.077f, 0.630f, 0.340f, 0.3127f, 0.3290f};

    default:

      return {};

  }

}

heif::Kr_Kb heif::get_Kr_Kb(uint16_t matrix_coefficients_idx, uint16_t primaries_idx)

{

  Kr_Kb result;

  if (matrix_coefficients_idx == 12 ||

      matrix_coefficients_idx == 13) {

    primaries p = get_colour_primaries(primaries_idx);

    float zr = 1 - (p.redX + p.redY);

    float zg = 1 - (p.greenX + p.greenY);

    float zb = 1 - (p.blueX + p.blueY);

    float zw = 1 - (p.whiteX + p.whiteY);

    float denom = p.whiteY * (p.redX * (p.greenY * zb - p.blueY * zg) + p.greenX * (p.blueY * zr - p.redY * zb) +

                              p.blueX * (p.redY * zg - p.greenY * zr));

    if (denom == 0.0f) {

      return result;

    }

    result.Kr = (p.redY * (p.whiteX * (p.greenY * zb - p.blueY * zg) + p.whiteY * (p.blueX * zg - p.greenX * zb) +

                           zw * (p.greenX * p.blueY - p.blueX * p.greenY))) / denom;

    result.Kb = (p.blueY * (p.whiteX * (p.redY * zg - p.greenY * zr) + p.whiteY * (p.greenX * zr - p.redX * zg) +

                            zw * (p.redX * p.greenY - p.greenX * p.redY))) / denom;

  }

  else

    switch (matrix_coefficients_idx) {

      case 1:

        result.Kr = 0.2126f;

        result.Kb = 0.0722f;

        break;

      case 4:

        result.Kr = 0.30f;

        result.Kb = 0.11f;

        break;

      case 5:

      case 6:

        result.Kr = 0.299f;

        result.Kb = 0.114f;

        break;

      case 7:

        result.Kr = 0.212f;

        result.Kb = 0.087f;

        break;

      case 9:

      case 10:

        result.Kr = 0.2627f;

        result.Kb = 0.0593f;

        break;

      default:;

    }

  return result;

}

heif::YCbCr_to_RGB_coefficients heif::YCbCr_to_RGB_coefficients::defaults()

{

  YCbCr_to_RGB_coefficients coeffs;

  coeffs.defined = true;

  coeffs.r_cr = 1.402f;

  coeffs.g_cb = -0.344136f;

  coeffs.g_cr = -0.714136f;

  coeffs.b_cb = 1.772f;

  return coeffs;

}

heif::YCbCr_to_RGB_coefficients

heif::get_YCbCr_to_RGB_coefficients(uint16_t matrix_coefficients_idx, uint16_t primaries_idx)

{

  YCbCr_to_RGB_coefficients coeffs;

  Kr_Kb k = get_Kr_Kb(matrix_coefficients_idx, primaries_idx);

  if (k.Kb != 0 || k.Kr != 0) { // both will be != 0 when valid

    coeffs.defined = true;

    coeffs.r_cr = 2 * (-k.Kr + 1);

    coeffs.g_cb = 2 * k.Kb * (-k.Kb + 1) / (k.Kb + k.Kr - 1);

    coeffs.g_cr = 2 * k.Kr * (-k.Kr + 1) / (k.Kb + k.Kr - 1);

    coeffs.b_cb = 2 * (-k.Kb + 1);

  }

  else {

    coeffs = YCbCr_to_RGB_coefficients::defaults();

  }

  return coeffs;

}

heif::RGB_to_YCbCr_coefficients

heif::get_RGB_to_YCbCr_coefficients(uint16_t matrix_coefficients_idx, uint16_t primaries_idx)

{

  RGB_to_YCbCr_coefficients coeffs;

  Kr_Kb k = get_Kr_Kb(matrix_coefficients_idx, primaries_idx);

  if (k.Kb != 0 || k.Kr != 0) { // both will be != 0 when valid

    coeffs.defined = true;

    coeffs.c[0][0] = k.Kr;

    coeffs.c[0][1] = 1 - k.Kr - k.Kb;

    coeffs.c[0][2] = k.Kb;

    coeffs.c[1][0] = -k.Kr / (1 - k.Kb) / 2;

    coeffs.c[1][1] = -(1 - k.Kr - k.Kb) / (1 - k.Kb) / 2;

    coeffs.c[1][2] = 0.5f;

    coeffs.c[2][0] = 0.5f;

    coeffs.c[2][1] = -(1 - k.Kr - k.Kb) / (1 - k.Kr) / 2;

    coeffs.c[2][2] = -k.Kb / (1 - k.Kr) / 2;

  }

  else {

    coeffs = RGB_to_YCbCr_coefficients::defaults();

  }

  return coeffs;

}

heif::RGB_to_YCbCr_coefficients heif::RGB_to_YCbCr_coefficients::defaults()

{

  RGB_to_YCbCr_coefficients coeffs;

  coeffs.defined = true;

  coeffs.c[0][0] = 0.299f;

  coeffs.c[0][1] = 0.587f;

  coeffs.c[0][2] = 0.114f;

  coeffs.c[1][0] = -0.168735f;

  coeffs.c[1][1] = -0.331264f;

  coeffs.c[1][2] = 0.5f;

  coeffs.c[2][0] = 0.5f;

  coeffs.c[2][1] = -0.418688f;

  coeffs.c[2][2] = -0.081312f;

  return coeffs;

}