curve.h

// SPDX-FileCopyrightText: © 2020, 2023-2026 Alexandros Theodotou <alex@zrythm.org>
// SPDX-License-Identifier: LicenseRef-ZrythmLicense
 
#pragma once
 
#include <QObject>
#include <QtQmlIntegration/qqmlintegration.h>
 
#include <boost/describe/class.hpp>
#include <nlohmann/json_fwd.hpp>
 
using namespace std::string_view_literals;
 
namespace zrythm::dsp
{

class CurveOptions final
{
  Q_GADGET
 
public:
  enum class Algorithm
  {
    Exponent,

    SuperEllipse,

    Vital,

    Pulse,

    Logarithmic,
  };
  Q_ENUM (Algorithm)
 
  
  static constexpr double SUPERELLIPSE_CURVINESS_BOUND = 0.82;
  static constexpr double EXPONENT_CURVINESS_BOUND = 0.95;
  static constexpr double VITAL_CURVINESS_BOUND = 1.00;
 
public:
  // Rule of 0
  CurveOptions () = default;
  CurveOptions (double curviness, Algorithm algo) noexcept;

  [[gnu::hot]] double
  get_normalized_y (double x, bool start_higher) const noexcept;
 
  friend bool operator== (const CurveOptions &a, const CurveOptions &b);
 
private:
  static constexpr auto kCurvinessKey = "curviness"sv;
  static constexpr auto kAlgorithmKey = "algorithm"sv;
  friend void           to_json (nlohmann::json &j, const CurveOptions &opts);
  friend void           from_json (const nlohmann::json &j, CurveOptions &opts);
 
public:
  double curviness_{ 0.0 };

  Algorithm algo_{};
 
  BOOST_DESCRIBE_CLASS (CurveOptions, (), (curviness_, algo_), (), ())
};

class CurveOptionsQmlAdapter : public QObject
{
  Q_OBJECT
  Q_PROPERTY (
    double curviness READ curviness WRITE setCurviness NOTIFY curvinessChanged)
  Q_PROPERTY (
    zrythm::dsp::CurveOptions::Algorithm algorithm READ algorithm WRITE
      setAlgorithm NOTIFY algorithmChanged)
  QML_NAMED_ELEMENT (CurveOptions)
  QML_UNCREATABLE ("")
 
public:
  CurveOptionsQmlAdapter (CurveOptions &options, QObject * parent = nullptr)
      : QObject (parent), options_ (options)
  {
  }
 
  // ========================================================================
  // QML Interface
  // ========================================================================
 
  double        curviness () const { return options_.curviness_; }
  void          setCurviness (double curviness);
  Q_SIGNAL void curvinessChanged (double curviness);
 
  zrythm::dsp::CurveOptions::Algorithm algorithm () const
  {
    return options_.algo_;
  }
  void setAlgorithm (zrythm::dsp::CurveOptions::Algorithm algorithm);
  Q_SIGNAL void
  algorithmChanged (zrythm::dsp::CurveOptions::Algorithm algorithm);
 
  Q_INVOKABLE double normalizedY (double x, bool startHigher) const
  {
    return options_.get_normalized_y (x, startHigher);
  }
 
  // ========================================================================
 
private:
  CurveOptions &options_;
};

float
evaluate_curve (
  float                   value_a,
  float                   value_b,
  CurveOptions::Algorithm algo,
  float                   curviness,
  double                  ratio) noexcept [[clang::nonblocking]];
 
} // namespace zrythm::dsp
 
// These may be used in the UI eventually, but it's probably better to have a
// method in CurveOptionsQmlAdapter that returns them (TODO)
#if 0
DEFINE_ENUM_FORMATTER (
  zrythm::dsp::CurveOptions::Algorithm,
  CurveOptions_Algorithm,
  QT_TR_NOOP_UTF8 ("Exponent"),
  QT_TR_NOOP_UTF8 ("Superellipse"),
  "Vital",
  QT_TR_NOOP_UTF8 ("Pulse"),
  QT_TR_NOOP_UTF8 ("Logarithmic"));
#endif