Scrubbing.h

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/**********************************************************************
 
Audacity: A Digital Audio Editor
 
Scrubbing.h
 
Paul Licameli split from TrackPanel.cpp
 
**********************************************************************/
 
#ifndef __AUDACITY_SCRUBBING__
#define __AUDACITY_SCRUBBING__
 
#include <thread>
#include <vector>
#include <wx/event.h>
#include <wx/longlong.h>
 
#include "../../ScrubState.h" // for ScrubbingOptions
#include "ClientData.h" // to inherit
#include "Prefs.h" // to inherit
#include "../../widgets/Overlay.h" // to inherit
#include "CommandContext.h"
#include "Identifier.h"
 
class AudacityProject;
class TranslatableString;
 
// Conditionally compile either a separate thead, or else use a timer in the main
// thread, to poll the mouse and update scrubbing speed and direction.  The advantage of
// a thread may be immunity to choppy scrubbing in case redrawing takes too much time.
#ifdef __WXGTK__
// Unfortunately some things the thread needs to do are not thread safe
#else
#define USE_SCRUB_THREAD
#endif
 
// Scrub state object
class AUDACITY_DLL_API Scrubber final
   : public wxEvtHandler
   , public ClientData::Base
   , private PrefsListener
   , public std::enable_shared_from_this< Scrubber >
{
public:
   static Scrubber &Get( AudacityProject &project );
   static const Scrubber &Get( const AudacityProject &project );
 
   explicit
   Scrubber(AudacityProject *project);
   Scrubber( const Scrubber & ) = delete;
   Scrubber &operator=( const Scrubber & ) = delete;
   ~Scrubber();
 
   static bool ShouldScrubPinned();
 
   // Assume xx is relative to the left edge of TrackPanel!
   void MarkScrubStart(wxCoord xx, bool smoothScrolling, bool seek);
 
   // Returns true iff the event should be considered consumed by this:
   // Assume xx is relative to the left edge of TrackPanel!
   bool MaybeStartScrubbing(wxCoord xx);
   bool StartKeyboardScrubbing(double time0, bool backwards);
   double GetKeyboardScrubbingSpeed();
 
   void ContinueScrubbingUI();
   void ContinueScrubbingPoll();
 
   // This is meant to be called only from ProjectAudioManager
   void StopScrubbing();
 
   wxCoord GetScrubStartPosition() const
   { return mScrubStartPosition; }
 
   bool WasSpeedPlaying() const
   { return mSpeedPlaying;}
   bool IsSpeedPlaying() const
   { return IsScrubbing() && mSpeedPlaying; }
   bool WasKeyboardScrubbing() const
   { return mKeyboardScrubbing; }
   bool IsKeyboardScrubbing() const
   { return IsScrubbing() && mKeyboardScrubbing; }
   void SetBackwards(bool backwards)
   { mBackwards = backwards;}
   bool IsBackwards() const
   { return mBackwards;}
   // True iff the user has clicked to start scrub and not yet stopped,
   // but IsScrubbing() may yet be false
   bool HasMark() const
   { return GetScrubStartPosition() >= 0; }
   bool IsScrubbing() const;
 
   bool IsScrollScrubbing() const // If true, implies HasMark()
   { return mSmoothScrollingScrub; }
   void SetScrollScrubbing(bool value)
   { mSmoothScrollingScrub = value; }
 
   bool ChoseSeeking() const;
   void SetMayDragToSeek( bool value ) { mMayDragToSeek = value; }
   bool MayDragToSeek() const { return mMayDragToSeek; }
   bool TemporarilySeeks() const;
   bool Seeks() const;
   bool Scrubs() const;
   bool ShowsBar() const;
 
   void Cancel()
   { mCancelled = true; }
 
   bool ShouldDrawScrubSpeed();
   double FindScrubSpeed(bool seeking, double time) const;
   double GetMaxScrubSpeed() const { return mOptions.maxSpeed; }
 
   void HandleScrollWheel(int steps);
 
   // This returns the same as the enabled state of the menu items:
   bool CanScrub() const;
 
   // For popup
   void PopulatePopupMenu(wxMenu &menu);
 
   void OnScrubOrSeek(bool seek);
   void OnScrub(const CommandContext&);
   void OnSeek(const CommandContext&);
   void OnToggleScrubRuler(const CommandContext&);
 
   void OnKeyboardScrubBackwards(const CommandContext&);
   void OnKeyboardScrubForwards(const CommandContext&);
   void DoKeyboardScrub(bool backwards, bool keyUp);
 
   // Convenience wrapper for the above
   template<void (Scrubber::*pfn)(const CommandContext&)>
      void Thunk(wxCommandEvent &)
         { (this->*pfn)(*mProject); }
 
   // A string to put in the leftmost part of the status bar
   // when scrub or seek is in progress, or else empty.
   const TranslatableString &GetUntranslatedStateString() const;
   wxString StatusMessageForWave() const;
 
   void Pause(bool paused);
   bool IsPaused() const;
   void CheckMenuItems();
 
   bool IsTransportingPinned() const;
 
   void SetSeekPress( bool value ) { mScrubSeekPress = value; }
 
private:
   void UpdatePrefs() override;
 
   void StartPolling();
   void StopPolling();
   void DoScrub(bool seek);
   void OnActivateOrDeactivateApp(wxActivateEvent & event);
 
   void ScrubPollerThread();
   void JoinThread();
 
private:
   int mScrubToken;
   int mScrubSpeedDisplayCountdown;
   wxCoord mScrubStartPosition;
   wxCoord mLastScrubPosition {};
   bool mScrubSeekPress {};
   bool mSmoothScrollingScrub;
 
   bool mPaused{};
   bool mSeeking {};
   bool mSpeedPlaying{true};
   bool mKeyboardScrubbing{};
   bool mBackwards{};
   bool mDragging {};
 
   bool mCancelled {};
 
   int mLogMaxScrubSpeed;
 
   AudacityProject *mProject;
 
   DECLARE_EVENT_TABLE()
 
#ifdef USE_SCRUB_THREAD
   // Course corrections in playback are done in a helper thread, unhindered by
   // the complications of the main event dispatch loop
   std::thread mThread;
   std::atomic<bool> mFinishThread{ false };
#endif
 
   // Other periodic update of the UI must be done in the main thread,
   // by this object which is driven by timer events.
   class ScrubPoller;
   std::unique_ptr<ScrubPoller> mPoller;
 
   ScrubbingOptions mOptions;
   double mMaxSpeed { 1.0 };
 
   bool mShowScrubbing { false };
   bool mMayDragToSeek{ false };
};
 
#endif