SnapUtils.h

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/*  SPDX-License-Identifier: GPL-2.0-or-later */
/*!********************************************************************
 
  Audacity: A Digital Audio Editor
 
  SnapUtils.h
 
  Dmitry Vedenko
 
**********************************************************************/
#pragma once
 
#include "Callable.h"
#include "Prefs.h"
#include "Registry.h"
 
#include <functional>
#include <string_view>
 
enum class SnapMode
{
   SNAP_OFF,
   SNAP_NEAREST,
   SNAP_PRIOR
};
 
extern SNAPPING_API StringSetting SnapToSetting;
extern SNAPPING_API EnumSetting<SnapMode> SnapModeSetting;
 
SNAPPING_API SnapMode ReadSnapMode();
SNAPPING_API Identifier ReadSnapTo();
 
struct SnapRegistryGroup;
struct SnapRegistryItem;
struct SnapFunctionSuperGroup;
 
class AudacityProject;
 
struct SNAPPING_API SnapResult final
{
 
   double time {};
   bool snapped {};
};
 
struct SnapRegistryTraits : Registry::DefaultTraits{
   using LeafTypes = List<SnapRegistryItem>;
   using NodeTypes = List<SnapRegistryGroup, SnapFunctionSuperGroup>;
};
using SnapRegistryVisitor = Registry::VisitorFunctions<SnapRegistryTraits>;
 
struct SnapRegistryGroupData {
   const TranslatableString label;
   const bool inlined;
};
 
struct SNAPPING_API SnapRegistryGroup final
   : Composite::Extension<
      Registry::GroupItem<SnapRegistryTraits>,
      SnapRegistryGroupData,
      const Identifier &
   >
{
   using Extension::Extension;
   ~SnapRegistryGroup() override;
   bool Inlined() const { return inlined; }
   const TranslatableString &Label() const { return label; }
};
 
struct SNAPPING_API SnapRegistryItem : public Registry::SingleItem
{
   SnapRegistryItem(
      const Identifier& internalName, const TranslatableString& label);
   ~SnapRegistryItem() override;
 
   const TranslatableString label;
 
   virtual SnapResult Snap(const AudacityProject& project, double time, bool nearest) const = 0;
   virtual SnapResult SingleStep(const AudacityProject& project, double time, bool upwards) const = 0;
};
 
std::unique_ptr<SnapRegistryItem> TimeInvariantSnapFunction(
   const Identifier& functionId, const TranslatableString& label,
   double multiplier);
 
using MultiplierFunctor = std::function<double(const AudacityProject&)>;
 
std::unique_ptr<SnapRegistryItem> TimeInvariantSnapFunction(
   const Identifier& functionId, const TranslatableString& label,
   MultiplierFunctor functor);
 
constexpr auto SnapFunctionGroup = Callable::UniqueMaker<
   SnapRegistryGroup, const Identifier &, SnapRegistryGroupData>();
 
struct SNAPPING_API SnapFunctionsRegistry final {
   static Registry::GroupItem<SnapRegistryTraits>& Registry();
 
   static void Visit(const SnapRegistryVisitor& visitor);
 
   static const SnapRegistryItem* Find(const Identifier& id);
 
   static SnapResult Snap(const Identifier& id, const AudacityProject& project, double time, bool nearest);
   static SnapResult SingleStep(
      const Identifier& id, const AudacityProject& project, double time,
      bool upwards);
};
 
using SnapRegistryItemRegistrator =
   Registry::RegisteredItem<SnapFunctionsRegistry>;
 
struct SnapFunctionSuperGroup : Composite::Extension<
   Registry::GroupItem<SnapRegistryTraits>, void, const Identifier&
> {
   using Extension::Extension;
};
 
constexpr auto SnapFunctionItems =
   Callable::UniqueMaker<SnapFunctionSuperGroup>();