/*

 * Copyright © 2023  Behdad Esfahbod

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

#ifndef HB_SUBSET_INSTANCER_SOLVER_HH

#define HB_SUBSET_INSTANCER_SOLVER_HH

#include "hb.hh"

/* pre-normalized distances */

struct TripleDistances

{

  TripleDistances (): negative (1.0), positive (1.0) {}

  TripleDistances (double neg_, double pos_): negative (neg_), positive (pos_) {}

  TripleDistances (double min, double default_, double max)

  {

    negative = default_ - min;

    positive = max - default_;

  }

  double negative;

  double positive;

};

struct Triple

{

  Triple () = default;

  Triple (double minimum_, double middle_, double maximum_) :

    minimum (minimum_), middle (middle_), maximum (maximum_) {}

  bool operator == (const Triple &o) const

  {

    return minimum == o.minimum &&

     middle  == o.middle  &&

     maximum == o.maximum;

  }

  bool operator != (const Triple o) const

  { return !(*this == o); }

  bool is_point () const

  { return minimum == middle && middle == maximum; }

  bool contains (double point) const

  { return minimum <= point && point <= maximum; }

  /* from hb_array_t hash ()*/

  uint32_t hash () const

  {

    uint32_t current = /*cbf29ce4*/0x84222325;

    current = current ^ hb_hash (minimum);

    current = current * 16777619;

    current = current ^ hb_hash (middle);

    current = current * 16777619;

    current = current ^ hb_hash (maximum);

    current = current * 16777619;

    return current;

  }

  double minimum = 0;

  double middle = 0;

  double maximum = 0;

};

using rebase_tent_result_item_t = hb_pair_t<double, Triple>;

using rebase_tent_result_t = hb_vector_t<rebase_tent_result_item_t>;

/* renormalize a normalized value v to the range of an axis,

 * considering the prenormalized distances as well as the new axis limits.

 * Ported from fonttools */

HB_INTERNAL double renormalizeValue (double v, const Triple &triple,

                                    const TripleDistances &triple_distances,

                                    bool extrapolate = true);

/* Given a tuple (lower,peak,upper) "tent" and new axis limits

 * (axisMin,axisDefault,axisMax), solves how to represent the tent

 * under the new axis configuration.  All values are in normalized

 * -1,0,+1 coordinate system. Tent values can be outside this range.

 *

 * Return value: a list of tuples. Each tuple is of the form

 * (scalar,tent), where scalar is a multipler to multiply any

 * delta-sets by, and tent is a new tent for that output delta-set.

 * If tent value is Triple{}, that is a special deltaset that should

 * be always-enabled (called "gain").

 */

HB_INTERNAL void rebase_tent (Triple tent,

            Triple axisLimit,

            TripleDistances axis_triple_distances,

            rebase_tent_result_t &out,

            rebase_tent_result_t &scratch);

#endif /* HB_SUBSET_INSTANCER_SOLVER_HH */