Viewport.h

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/**********************************************************************
 
Audacity: A Digital Audio Editor
 
Viewport.h
 
Paul Licameli split from ProjectWindow.h
 
**********************************************************************/
 
#ifndef __AUDACITY_VIEWPORT__
#define __AUDACITY_VIEWPORT__
 
#include "ClientData.h"
#include "Observer.h"
 
class AudacityProject;
class Track;
class TrackList;
 
class VIEWPORT_API ViewportCallbacks {
public:
   virtual ~ViewportCallbacks();
 
   virtual std::pair<int, int> ViewportSize() const = 0;
 
   virtual unsigned MinimumTrackHeight() = 0;
   virtual bool IsTrackMinimized(const Track &track) = 0;
   virtual void SetMinimized(Track &track, bool minimized) = 0;
   virtual int GetTrackHeight(const Track &track) = 0;
   virtual void SetChannelHeights(Track &track, unsigned height) = 0;
   virtual int GetTotalHeight(const TrackList &trackList) = 0;
 
   virtual int GetHorizontalThumbPosition() const = 0;
   virtual int GetHorizontalThumbSize() const = 0;
   virtual int GetHorizontalRange() const = 0;
   virtual void SetHorizontalThumbPosition(int viewStart) = 0;
   virtual void SetHorizontalScrollbar(int position, int thumbSize,
      int range, int pageSize, bool refresh) = 0;
   virtual void ShowHorizontalScrollbar(bool shown) = 0;
 
   virtual int GetVerticalThumbPosition() const = 0;
   virtual int GetVerticalThumbSize() const = 0;
   virtual int GetVerticalRange() const = 0;
   virtual void SetVerticalThumbPosition(int viewStart) = 0;
   virtual void SetVerticalScrollbar(int position, int thumbSize,
      int range, int pageSize, bool refresh) = 0;
   virtual void ShowVerticalScrollbar(bool shown) = 0;
 
   virtual void SetToDefaultSize() = 0;
};
 
struct ViewportMessage {
   const bool rescroll;
   const bool scrollbarVisibilityChanged;
   const bool resize;
};
 
class VIEWPORT_API Viewport final
   : public Observer::Publisher<ViewportMessage>
   , public ClientData::Base
   , public std::enable_shared_from_this<Viewport>
{
public:
   static Viewport &Get(AudacityProject &project);
   static const Viewport &Get(const AudacityProject &project);
 
   explicit Viewport(AudacityProject &project);
   void SetCallbacks(std::unique_ptr<ViewportCallbacks> pCallbacks);
 
   double ScrollingLowerBoundTime() const;
 
   void DoScroll();
 
   void ScrollToStart(bool extend);
 
   void ScrollToEnd(bool extend);
 
   void ScrollToTop();
   void ScrollToBottom();
 
   void ScrollIntoView(double pos);
 
   void ScrollIntoView(int x);
 
   void OnScrollLeft();
 
   void OnScrollRight();
 
   void OnScrollLeftButton();
 
   void OnScrollRightButton();
 
   void OnScroll();
 
   // Scroll vertically. A positive argument makes the window
   // scroll down, while a negative argument scrolls up.
   bool ScrollUpDown(int delta);
 
   void SetHorizontalThumb(double scrollto, bool doScroll = true);
 
   void Zoom(double pixelsPerSecond);
 
   void ZoomBy(double multiplier);
 
   void ZoomAboutSelection(double multiplier);
 
   void ZoomAboutCenter(double multiplier);
 
   void ZoomFitHorizontallyAndShowTrack(Track *pTrack);
 
   void ShowTrack(const Track &track);
 
   double GetZoomOfToFit() const;
 
   void ZoomFitHorizontally();
 
   void ZoomFitVertically();
 
   void ExpandAllTracks();
   void CollapseAllTracks();
 
   void UpdateScrollbarsForTracks();
 
   void HandleResize();
 
   void ReinitScrollbars() { mbInitializingScrollbar = true; }
 
   void Redraw();
 
   void SetToDefaultSize();
 
private:
   // How many pixels are covered by the period from lowermost scrollable time, to the given time:
   // PRL: Bug1197: we seem to need to compute all in double, to avoid differing results on Mac
   double PixelWidthBeforeTime(double scrollto) const;
 
   void FinishAutoScroll();
 
   void OnUndoPushedModified();
   void OnUndoRedo();
   void OnUndoReset();
 
   AudacityProject &mProject;
   std::unique_ptr<ViewportCallbacks> mpCallbacks{};
 
   const Observer::Subscription
        mSnappingChangedSubscription
      , mUndoSubscription
   ;
 
   double total{ 1.0 };                // total width in secs
 
   // Current horizontal scroll bar positions, in pixels
   wxInt64 sbarH{ 0 };
   wxInt64 sbarScreen{ 1 };
   wxInt64 sbarTotal{ 1 };
 
   // Internal wxScrollbar positions are only int in range, so multiply
   // the above values with the following member to get the actual
   // scroll bar positions as reported by the horizontal wxScrollbar's members
   // i.e. units are scroll increments per pixel
   double sbarScale{ 1.0 };
 
   // Vertical scroll step
   int scrollStep{ 16 };
 
   bool mAutoScrolling{ false };
   bool mbInitializingScrollbar{ false };
};
 
#endif