editing_context.h

Go to the documentation of this file.

/*
 * Copyright (C) 2005-2007 Doug McLain <doug@nostar.net>
 * Copyright (C) 2005-2018 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2005 Karsten Wiese <fzuuzf@googlemail.com>
 * Copyright (C) 2006-2009 Sampo Savolainen <v2@iki.fi>
 * Copyright (C) 2006-2015 David Robillard <d@drobilla.net>
 * Copyright (C) 2006-2017 Tim Mayberry <mojofunk@gmail.com>
 * Copyright (C) 2007-2012 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2008-2011 Sakari Bergen <sakari.bergen@beatwaves.net>
 * Copyright (C) 2008 Hans Baier <hansfbaier@googlemail.com>
 * Copyright (C) 2013-2015 Colin Fletcher <colin.m.fletcher@googlemail.com>
 * Copyright (C) 2013-2019 Robin Gareus <robin@gareus.org>
 * Copyright (C) 2014-2017 Nick Mainsbridge <mainsbridge@gmail.com>
 * Copyright (C) 2014-2019 Ben Loftis <ben@harrisonconsoles.com>
 * Copyright (C) 2015-2019 Damien Zammit <damien@zamaudio.com>
 * Copyright (C) 2015 André Nusser <andre.nusser@googlemail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#pragma once
 
#include "pbd/signals.h"
 
#include "temporal/timeline.h"
#include "temporal/scope.h"
 
#include "ardour/midi_operator.h"
#include "ardour/session_handle.h"
#include "ardour/types.h"
 
#include "canvas/ruler.h"
 
#include "widgets/ardour_button.h"
#include "widgets/ardour_dropdown.h"
#include "widgets/ardour_spacer.h"
 
#include "axis_provider.h"
#include "editing.h"
#include "editor_items.h"
#include "selection.h"
 
using ARDOUR::samplepos_t;
using ARDOUR::samplecnt_t;
 
namespace Temporal {
        class TempoMap;
}
 
namespace ARDOUR {
        class Strum;
}
 
class XMLNode;
 
class ControlPoint;
class CursorContext;
class DragManager;
class EditorCursor;
class EditNoteDialog;
class GridLines;
class MidiRegionView;
class MidiView;
class MouseCursors;
class VerboseCursor;
class TrackViewList;
class Selection;
class SelectionMemento;
class SelectableOwner;
 
class EditingContext : public ARDOUR::SessionHandlePtr, public AxisViewProvider, public Temporal::ScopedTempoMapOwner, public virtual sigc::trackable
{
 public:
        EditingContext (std::string const &);
        ~EditingContext ();
 
        std::string editor_name() const { return _name; }
        std::string scope_name() const { return _name; }
 
        void set_session (ARDOUR::Session*);
 
        Temporal::TimeDomain time_domain () const;
 
        DragManager* drags () const {
                return _drags;
        }
 
        bool drag_active () const;
        bool preview_video_drag_active () const;
 
        virtual std::list<SelectableOwner*> selectable_owners() = 0;
 
        virtual ArdourCanvas::Duple upper_left() const { return ArdourCanvas::Duple (0, 0); }
 
        virtual void select_all_within (Temporal::timepos_t const &, Temporal::timepos_t const &, double, double, std::list<SelectableOwner*> const &, ARDOUR::SelectionOperation, bool) = 0;
        virtual void get_per_region_note_selection (std::list<std::pair<PBD::ID, std::set<std::shared_ptr<Evoral::Note<Temporal::Beats> > > > >&) const = 0;
        virtual void get_regionviews_by_id (PBD::ID const id, RegionSelection & regions) const = 0;
        virtual StripableTimeAxisView* get_stripable_time_axis_by_id (const PBD::ID& id) const = 0;
        virtual TrackViewList axis_views_from_routes (std::shared_ptr<ARDOUR::RouteList>) const = 0;
 
        virtual ARDOUR::Location* find_location_from_marker (ArdourMarker*, bool&) const = 0;
        virtual ArdourMarker* find_marker_from_location_id (PBD::ID const&, bool) const = 0;
        virtual TempoMarker* find_marker_for_tempo (Temporal::TempoPoint const &) = 0;
        virtual MeterMarker* find_marker_for_meter (Temporal::MeterPoint const &) = 0;
 
 
        EditorCursor* playhead_cursor () const { return _playhead_cursor; }
        EditorCursor* snapped_cursor () const { return _snapped_cursor; }
 
        virtual void maybe_autoscroll (bool, bool, bool from_headers) = 0;
        virtual void stop_canvas_autoscroll () = 0;
        virtual bool autoscroll_active() const = 0;
 
        void scroll_left_step ();
        void scroll_right_step ();
        void scroll_left_half_page ();
        void scroll_right_half_page ();
 
        virtual void redisplay_grid (bool immediate_redraw) = 0;
        virtual Temporal::timecnt_t get_nudge_distance (Temporal::timepos_t const & pos, Temporal::timecnt_t& next) const = 0;
 
        Temporal::timecnt_t relative_distance (Temporal::timepos_t const & origin, Temporal::timecnt_t const & duration, Temporal::TimeDomain domain);
        Temporal::timecnt_t snap_relative_time_to_relative_time (Temporal::timepos_t const & origin, Temporal::timecnt_t const & x, bool ensure_snap) const;
 
        void set_follow_playhead (bool yn, bool catch_up = true);
 
        void toggle_follow_playhead ();
 
        bool follow_playhead () const;
 
        Temporal::timepos_t get_preferred_edit_position (Editing::EditIgnoreOption eio = Editing::EDIT_IGNORE_NONE,
                                                         bool use_context_click = false,
                                                         bool from_outside_canvas = false) {
                return _get_preferred_edit_position (eio, use_context_click, from_outside_canvas);
        }
 
        virtual void instant_save() = 0;
 
        virtual void begin_selection_op_history () = 0;
        virtual void begin_reversible_selection_op (std::string cmd_name) = 0;
        virtual void commit_reversible_selection_op () = 0;
        virtual void abort_reversible_selection_op () = 0;
        virtual void undo_selection_op () = 0;
        virtual void redo_selection_op () = 0;
 
        /* Some EditingContexts may defer to the Session, which IS-A
         * HistoryOwner (Editor does this).
         *
         * Others may themselves have the IS-A HistoryOwner inheritance, and so
         * they just proxy back to their base class (CueEditor does this).
         */
 
        virtual PBD::HistoryOwner& history() = 0;
 
        virtual void add_command (PBD::Command *) = 0;
        virtual void add_commands (std::vector<PBD::Command *>) = 0;
        virtual void begin_reversible_command (std::string cmd_name) = 0;
        virtual void begin_reversible_command (GQuark) = 0;
        virtual void abort_reversible_command () = 0;
        virtual void commit_reversible_command () = 0;
 
        virtual void set_selected_midi_region_view (MidiRegionView&);
 
        samplecnt_t get_current_zoom () const { return samples_per_pixel; }
 
        void temporal_zoom_step (bool zoom_out);
        void temporal_zoom_step_scale (bool zoom_out, double scale);
        void temporal_zoom_step_mouse_focus (bool zoom_out);
        void temporal_zoom_step_mouse_focus_scale (bool zoom_out, double scale);
 
        void calc_extra_zoom_edges(samplepos_t &start, samplepos_t &end);
        void temporal_zoom (samplecnt_t samples_per_pixel);
        void temporal_zoom_by_sample (samplepos_t start, samplepos_t end);
        void temporal_zoom_to_sample (bool coarser, samplepos_t sample);
 
        double timeline_origin() const { return _timeline_origin; }
 
        /* NOTE: these functions assume that the "pixel" coordinate is
           in canvas coordinates. These coordinates already take into
           account any scrolling offsets.
        */
 
        samplepos_t pixel_to_sample_from_event (double pixel) const {
 
                /* pixel can be less than zero when motion events are
                   processed. Since the pixel value is in canvas units (since
                   it comes from an event delivered to the canvas), we've
                   already run the window->canvas transform, that means that
                   the location *really* is "off to the right" and thus really
                   is "before the start".
                */
 
                if (pixel >= _timeline_origin) {
                        return (pixel - _timeline_origin) * samples_per_pixel;
                } else {
                        return 0;
                }
        }
 
        /* It makes no sense to ever call these functions to convert to or from a
         * non-timeline relative pixel position, so they all assume that is
         * what they are being asked to do.
         */
 
        samplepos_t pixel_to_sample (double pixel) const {
                return pixel * samples_per_pixel;
        }
 
        double sample_to_pixel (samplepos_t sample) const {
                return round (sample / (double) samples_per_pixel);
        }
 
        double sample_to_pixel_unrounded (samplepos_t sample) const {
                return (sample / (double) samples_per_pixel);
        }
 
        double time_to_pixel (Temporal::timepos_t const & pos) const;
        double time_to_pixel_unrounded (Temporal::timepos_t const & pos) const;
 
        double time_delta_to_pixel (Temporal::timepos_t const& start, Temporal::timepos_t const& end) const;
 
        /* deprecated, prefer time_delta_to_pixel
         * first taking the duation and then rounding leads to different results:
         * duration_to_pixels (start.distance(end)) != time_to_pixel (end) - time_to_pixel (start)
         */
        double duration_to_pixels (Temporal::timecnt_t const & pos) const;
        double duration_to_pixels_unrounded (Temporal::timecnt_t const & pos) const;
 
        samplecnt_t pixel_duration_to_samples (double pixels) const {
                return pixels * samples_per_pixel;
        }
 
        /* These two convert between timeline-relative x-axis pixel positions and
         * global canvas ones.
         */
 
        double timeline_to_canvas (double p) const { return p + _timeline_origin; }
        double canvas_to_timeline (double p) const { return p - _timeline_origin; }
 
        double visible_canvas_width () const { return _visible_canvas_width; }
        double visible_canvas_height () const { return _visible_canvas_height; }
 
        Temporal::timepos_t canvas_event_time (GdkEvent const*, double* px = 0, double* py = 0) const;
 
        samplepos_t canvas_event_sample (GdkEvent const * event, double* pcx = nullptr, double* pcy = nullptr) const;
 
        virtual bool canvas_note_event (GdkEvent* event, ArdourCanvas::Item*) = 0;
        virtual bool canvas_velocity_base_event (GdkEvent* event, ArdourCanvas::Item*) = 0;
        virtual bool canvas_velocity_event (GdkEvent* event, ArdourCanvas::Item*) = 0;
        virtual bool canvas_control_point_event (GdkEvent* event, ArdourCanvas::Item*, ControlPoint*) = 0;
        virtual bool canvas_cue_start_event (GdkEvent* event, ArdourCanvas::Item*) { return true; }
        virtual bool canvas_cue_end_event (GdkEvent* event, ArdourCanvas::Item*) { return true; }
        virtual bool canvas_bg_event (GdkEvent* event, ArdourCanvas::Item*) = 0;
 
        Temporal::Beats get_grid_type_as_beats (bool& success, Temporal::timepos_t const & position) const;
        Temporal::Beats get_draw_length_as_beats (bool& success, Temporal::timepos_t const & position) const;
 
        int32_t get_grid_beat_divisions (Editing::GridType gt) const;
        int32_t get_grid_music_divisions (Editing::GridType gt) const;
 
        Editing::GridType  grid_type () const;
        bool  grid_type_is_musical (Editing::GridType) const;
        bool  grid_musical () const;
 
        void cycle_snap_mode ();
        void next_grid_choice ();
        void prev_grid_choice ();
        void set_grid_type (Editing::GridType);
        void set_snap_mode (Editing::SnapMode);
 
        void set_draw_length (Editing::GridType);
        void set_draw_velocity (int);
        void set_draw_channel (int);
        virtual void set_note_mode (ARDOUR::NoteMode) {}
 
        Editing::GridType  draw_length () const;
        int                draw_velocity () const;
        int                draw_channel () const;
        virtual ARDOUR::NoteMode note_mode() const { return ARDOUR::Sustained; }
 
        Editing::SnapMode  snap_mode () const;
 
        virtual void snap_to (Temporal::timepos_t & first,
                              Temporal::RoundMode   direction = Temporal::RoundNearest,
                              ARDOUR::SnapPref      pref = ARDOUR::SnapToAny_Visual,
                              bool                  ensure_snap = false) const;
 
        virtual void snap_to_with_modifier (Temporal::timepos_t & first,
                                            GdkEvent const*       ev,
                                            Temporal::RoundMode   direction = Temporal::RoundNearest,
                                            ARDOUR::SnapPref      gpref = ARDOUR::SnapToAny_Visual,
                                            bool ensure_snap = false) const;
 
        virtual Temporal::timepos_t snap_to_bbt (Temporal::timepos_t const & start,
                                                 Temporal::RoundMode   direction,
                                                 ARDOUR::SnapPref    gpref) const;
 
        virtual double get_y_origin () const = 0;
 
        void reset_x_origin (samplepos_t);
        void reset_y_origin (double);
        void reset_zoom (samplecnt_t);
        virtual double max_extents_scale() const { return 1.0; }
        virtual void set_samples_per_pixel (samplecnt_t) = 0;
 
        virtual void cycle_zoom_focus ();
        virtual void set_zoom_focus (Editing::ZoomFocus) = 0;
        Editing::ZoomFocus zoom_focus () const;
 
        void zoom_focus_chosen (Editing::ZoomFocus);
 
        virtual void reposition_and_zoom (samplepos_t, double) = 0;
 
        sigc::signal<void> ZoomChanged;
 
        virtual Selection& get_selection() const { return *selection; }
        virtual Selection& get_cut_buffer () const { return *cut_buffer; }
 
        void reset_point_selection ();
 
        virtual void point_selection_changed () = 0;
 
        virtual void set_mouse_mode (Editing::MouseMode, bool force = false);
        virtual void step_mouse_mode (bool next) = 0;
        Editing::MouseMode current_mouse_mode () const;
        virtual Editing::MouseMode effective_mouse_mode () const { return current_mouse_mode(); }
        virtual void use_appropriate_mouse_mode_for_sections () {}
 
        virtual bool internal_editing() const = 0;
 
        virtual bool get_smart_mode() const { return false; }
 
        void choose_canvas_cursor_on_entry (ItemType);
 
        struct CursorRAII {
                CursorRAII (EditingContext& e, Gdk::Cursor* new_cursor)
                        : ec (e), old_cursor (ec.get_canvas_cursor ()) { ec.set_canvas_cursor (new_cursor); }
                ~CursorRAII () { ec.set_canvas_cursor (old_cursor); }
 
                EditingContext& ec;
                Gdk::Cursor* old_cursor;
        };
 
        virtual Gdk::Cursor* get_canvas_cursor () const;
        static MouseCursors const* cursors () {
                return _cursors;
        }
        virtual VerboseCursor& verbose_cursor () const {
                return *_verbose_cursor;
        }
 
        virtual void set_snapped_cursor_position (Temporal::timepos_t const & pos) = 0;
 
        static sigc::signal<void> DropDownKeys;
 
        PBD::Signal<void()> SnapChanged;
        PBD::Signal<void()> MouseModeChanged;
 
        typedef std::vector<MidiView*> MidiViews;
 
        /* MIDI actions, proxied to selected MidiRegionView(s) */
        ARDOUR::Quantize* get_quantize_op ();
        ARDOUR::Strum* get_strum_op (bool, bool);
        void apply_midi_note_edit_op (ARDOUR::MidiOperator& op, const RegionSelection& rs);
        void apply_midi_note_edit_op (ARDOUR::MidiOperator& op, const MidiViews& rs);
        PBD::Command* apply_midi_note_edit_op_to_region (ARDOUR::MidiOperator& op, MidiView& mrv);
        virtual void midi_action (void (MidiView::*method)());
        std::vector<MidiView*> filter_to_unique_midi_region_views (RegionSelection const & rs) const;
        std::vector<MidiView*> filter_to_unique_midi_region_views (MidiViews const & ms) const;
 
        void quantize_region ();
        void transform_region ();
        void legatize_region (bool shrink_only);
        void transpose_region ();
 
        void quantize_regions (const MidiViews& rs);
        void legatize_regions (const MidiViews& rs, bool shrink_only);
        void strum_notes (const MidiViews& rs, bool forward);
        void transform_regions (const MidiViews& rs);
        void transpose_regions (const MidiViews& rs);
 
        void edit_notes (MidiView*);
 
        static bool need_shared_actions;
        void register_midi_actions (Gtkmm2ext::Bindings*, std::string const &);
        void register_common_actions (Gtkmm2ext::Bindings*, std::string const &);
        void register_automation_actions (Gtkmm2ext::Bindings*, std::string const &);
        virtual void set_action_defaults ();
 
        ArdourCanvas::Rectangle* rubberband_rect;
 
        virtual ArdourCanvas::Container* get_trackview_group () const = 0;
        virtual ArdourCanvas::Container* get_noscroll_group() const = 0;
        virtual ArdourCanvas::ScrollGroup* get_hscroll_group () const = 0;
        virtual ArdourCanvas::ScrollGroup* get_cursor_scroll_group () const = 0;
        virtual bool canvas_playhead_cursor_event (GdkEvent* event, ArdourCanvas::Item*) { return false; }
 
        bool typed_event (ArdourCanvas::Item*, GdkEvent*, ItemType);
 
        void set_horizontal_position (double);
        double horizontal_position () const;
 
        virtual samplecnt_t current_page_samples() const = 0;
 
        virtual ArdourCanvas::GtkCanvasViewport* get_canvas_viewport() const = 0;
        virtual ArdourCanvas::GtkCanvas* get_canvas() const = 0;
 
        virtual void mouse_mode_chosen (Editing::MouseMode) = 0;
        Editing::MouseMode old_mouse_mode;
 
        bool on_velocity_scroll_event (GdkEventScroll*);
        void pre_render ();
 
        void select_automation_line (GdkEventButton*, ArdourCanvas::Item*, ARDOUR::SelectionOperation);
 
        virtual Gdk::Cursor* which_track_cursor () const = 0;
        virtual Gdk::Cursor* which_mode_cursor () const = 0;
        virtual Gdk::Cursor* which_trim_cursor (bool left_side) const = 0;
        virtual Gdk::Cursor* which_canvas_cursor (ItemType type) const = 0;
 
        void undo (uint32_t n = 1) { do_undo (n); }
 
        void redo (uint32_t n = 1) { do_redo (n); }
 
        virtual void history_changed() = 0;
        void update_undo_redo_actions (PBD::UndoHistory const &);
 
        virtual void set_canvas_cursor (Gdk::Cursor*);
 
        samplepos_t window_event_sample (GdkEvent const*, double* px = 0, double* py = 0) const;
 
        /* returns false if mouse pointer is not in track or marker canvas
         */
        bool mouse_sample (samplepos_t&, bool& in_track_canvas) const;
 
        /* editing actions */
 
        virtual void delete_ () = 0;
        virtual void paste (float times, bool from_context_menu) = 0;
        virtual void keyboard_paste () = 0;
        virtual void cut_copy (Editing::CutCopyOp) = 0;
 
        void cut ();
        void copy ();
        void alt_delete_ ();
 
        virtual void update_grid ();
 
        virtual bool allow_trim_cursors () const;
        virtual void make_a_region() {}
 
        void center_screen (samplepos_t);
        void reset_x_origin_to_follow_playhead ();
 
        void enable_automation_bindings ();
        void disable_automation_bindings ();
 
        /* playhead/screen stuff */
 
        void set_stationary_playhead (bool yn);
        void toggle_stationary_playhead ();
        bool stationary_playhead() const;
 
        bool dragging_playhead () const { return _dragging_playhead; }
 
        struct AutomationRecord {
                AutomationRecord () : state (0) , line (nullptr) {}
                AutomationRecord (XMLNode* s, const AutomationLine* l) : state (s) , line (l) {}
 
                XMLNode* state; 
                const AutomationLine* line; 
                std::shared_ptr<Evoral::ControlList> copy; 
        };
 
  protected:
        std::string _name;
        bool within_track_canvas;
 
        Glib::RefPtr<Gtk::ActionGroup> _midi_actions;
        Glib::RefPtr<Gtk::ActionGroup> _common_actions;
        Glib::RefPtr<Gtk::ActionGroup> _automation_actions;
        Glib::RefPtr<Gtk::ActionGroup> editor_actions;
        Glib::RefPtr<Gtk::ActionGroup> snap_actions;
        Glib::RefPtr<Gtk::ActionGroup> length_actions;
        Glib::RefPtr<Gtk::ActionGroup> channel_actions;
        Glib::RefPtr<Gtk::ActionGroup> velocity_actions;
        Glib::RefPtr<Gtk::ActionGroup> zoom_actions;
 
        virtual void load_shared_bindings ();
 
        virtual Gtk::Window* transient_parent () = 0;
 
        Editing::GridType  pre_internal_grid_type;
        Editing::SnapMode  pre_internal_snap_mode;
        Editing::GridType  internal_grid_type;
        Editing::SnapMode  internal_snap_mode;
 
        static std::vector<std::string> grid_type_strings;
        static std::vector<std::string> grid_type_short_labels;
 
        std::map<Editing::GridType, Glib::RefPtr<Gtk::RadioAction> > grid_actions;
        std::map<Editing::SnapMode, Glib::RefPtr<Gtk::RadioAction> > snap_mode_actions;
        std::map<Editing::GridType, Glib::RefPtr<Gtk::RadioAction> > draw_length_actions;
        std::map<Editing::MouseMode, Glib::RefPtr<Gtk::RadioAction> > mouse_mode_actions;
        std::map<ARDOUR::NoteMode, Glib::RefPtr<Gtk::RadioAction> > note_mode_actions;
        std::map<Editing::ZoomFocus, Glib::RefPtr<Gtk::RadioAction> > zoom_focus_actions;
        std::map<int, Glib::RefPtr<Gtk::RadioAction> > draw_velocity_actions;
        std::map<int, Glib::RefPtr<Gtk::RadioAction> > draw_channel_actions;
 
        void draw_channel_chosen (int);
        void draw_velocity_chosen (int);
        void draw_length_chosen (Editing::GridType);
        virtual void note_mode_chosen (ARDOUR::NoteMode) {}
 
        sigc::signal<void> DrawLengthChanged;
        sigc::signal<void> DrawVelocityChanged;
        sigc::signal<void> DrawChannelChanged;
 
        void draw_length_changed ();
        void draw_velocity_changed ();
        void draw_channel_changed ();
 
        double _timeline_origin;
 
        ArdourWidgets::ArdourDropdown grid_type_selector;
        void build_grid_type_menu ();
 
        ArdourWidgets::ArdourDropdown draw_length_selector;
        ArdourWidgets::ArdourDropdown draw_velocity_selector;
        ArdourWidgets::ArdourDropdown draw_channel_selector;
        void build_draw_midi_menus ();
 
        virtual void snap_mode_chosen (Editing::SnapMode);
        virtual void grid_type_chosen (Editing::GridType);
 
        ArdourWidgets::ArdourButton play_note_selection_button;
        ArdourWidgets::ArdourButton note_mode_button;
        ArdourWidgets::ArdourButton follow_playhead_button;
        ArdourWidgets::ArdourButton follow_edits_button;
 
        ArdourWidgets::ArdourButton zoom_in_button;
        ArdourWidgets::ArdourButton zoom_out_button;
        ArdourWidgets::ArdourButton full_zoom_button;
 
        Gtk::Label visible_channel_label;
        ArdourWidgets::ArdourDropdown visible_channel_selector;
 
        virtual void play_note_selection_clicked();
        virtual void note_mode_clicked() {}
        virtual void full_zoom_clicked() {};
        virtual void set_visible_channel (int) {}
 
        DragManager* _drags;
 
        ArdourWidgets::ArdourButton snap_mode_button;
        bool snap_mode_button_clicked (GdkEventButton*);
 
        virtual void mark_region_boundary_cache_dirty () {}
        virtual void update_tempo_based_rulers () {};
        virtual void show_rulers_for_grid () {};
 
        samplepos_t       _leftmost_sample;
 
        /* playhead and edit cursor */
 
        EditorCursor* _playhead_cursor;
        EditorCursor* _snapped_cursor;
 
        Glib::RefPtr<Gtk::ToggleAction> follow_playhead_action;
        void follow_playhead_chosen ();
 
        Glib::RefPtr<Gtk::ToggleAction> stationary_playhead_action;
        void stationary_playhead_chosen ();
 
        /* selection process */
 
        Selection* selection;
        Selection* cut_buffer;
        SelectionMemento* _selection_memento;
 
        std::list<XMLNode*> before; /* used in *_reversible_command */
 
        static MouseCursors* _cursors;
 
        std::unique_ptr<VerboseCursor> _verbose_cursor;
 
        samplecnt_t        samples_per_pixel;
 
        virtual Editing::ZoomFocus effective_zoom_focus() const { return zoom_focus(); }
 
        Temporal::timepos_t snap_to_bbt_via_grid (Temporal::timepos_t const & start,
                                                  Temporal::RoundMode   direction,
                                                  ARDOUR::SnapPref    gpref,
                                                  Editing::GridType   grid_type) const;
 
        virtual Temporal::timepos_t snap_to_grid (Temporal::timepos_t const & start,
                                                  Temporal::RoundMode   direction,
                                                  ARDOUR::SnapPref    gpref) const = 0;
 
        virtual void snap_to_internal (Temporal::timepos_t& first,
                                       Temporal::RoundMode    direction = Temporal::RoundNearest,
                                       ARDOUR::SnapPref     gpref = ARDOUR::SnapToAny_Visual,
                                       bool                 ensure_snap = false) const = 0;
 
        void check_best_snap (Temporal::timepos_t const & presnap, Temporal::timepos_t &test, Temporal::timepos_t &dist, Temporal::timepos_t &best) const;
 
        enum BBTRulerScale {
                bbt_show_many,
                bbt_show_64,
                bbt_show_16,
                bbt_show_4,
                bbt_show_1,
                bbt_show_quarters,
                bbt_show_eighths,
                bbt_show_sixteenths,
                bbt_show_thirtyseconds,
                bbt_show_sixtyfourths,
                bbt_show_onetwentyeighths
        };
 
        BBTRulerScale bbt_ruler_scale;
        uint32_t bbt_bars;
        uint32_t bbt_bar_helper_on;
 
        uint32_t count_bars (Temporal::Beats const & start, Temporal::Beats const & end) const;
        void compute_bbt_ruler_scale (samplepos_t lower, samplepos_t upper);
 
        double _track_canvas_width;
        double _visible_canvas_width;
        double _visible_canvas_height; 
 
        QuantizeDialog* quantize_dialog;
 
 
        virtual bool button_press_handler (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool button_press_handler_1 (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool button_press_handler_2 (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool button_release_handler (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool button_press_dispatch (GdkEventButton*) = 0;
        virtual bool button_release_dispatch (GdkEventButton*) = 0;
        virtual bool motion_handler (ArdourCanvas::Item*, GdkEvent*, bool from_autoscroll = false) = 0;
        virtual bool enter_handler (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool leave_handler (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool key_press_handler (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
        virtual bool key_release_handler (ArdourCanvas::Item*, GdkEvent*, ItemType) = 0;
 
        void popup_note_context_menu (ArdourCanvas::Item*, GdkEvent*);
        Gtk::Menu _note_context_menu;
 
        static Gtkmm2ext::Bindings* button_bindings;
        XMLNode* button_settings () const;
 
        virtual RegionSelection region_selection() = 0;
 
        void note_edit_done (int, EditNoteDialog*);
 
        MidiViews midiviews_from_region_selection (RegionSelection const &) const;
 
        friend class EditorSummary;
        Gtk::Adjustment     vertical_adjustment;
        Gtk::Adjustment     horizontal_adjustment;
 
        ArdourWidgets::ArdourButton mouse_select_button;
        ArdourWidgets::ArdourButton mouse_timefx_button;
        ArdourWidgets::ArdourButton mouse_grid_button;
        ArdourWidgets::ArdourButton mouse_cut_button;
        ArdourWidgets::ArdourButton mouse_move_button;
        ArdourWidgets::ArdourButton mouse_draw_button;
        ArdourWidgets::ArdourButton mouse_content_button;
 
        virtual void register_actions() = 0;
        void register_grid_actions ();
 
        void bind_mouse_mode_buttons ();
 
        Gtk::HBox snap_box;
        Gtk::HBox grid_box;
        Gtk::HBox draw_box;
 
        ArdourWidgets::ArdourVSpacer _grid_box_spacer;
        ArdourWidgets::ArdourVSpacer _draw_box_spacer;
 
        void pack_draw_box (bool with_channel);
        void pack_snap_box ();
 
        Gtkmm2ext::BindingSet bindings;
        Gtkmm2ext::Bindings* own_bindings;
 
        void set_common_editing_state (XMLNode const & node);
        void get_common_editing_state (XMLNode& node) const;
 
        struct VisualChange {
                enum Type {
                        TimeOrigin = 0x1,
                        ZoomLevel = 0x2,
                        YOrigin = 0x4,
                        VideoTimeline = 0x8
                };
 
                Type        pending;
                samplepos_t time_origin;
                samplecnt_t samples_per_pixel;
                double      y_origin;
 
                int idle_handler_id;
                bool being_handled;
 
                VisualChange() : pending ((VisualChange::Type) 0), time_origin (0), samples_per_pixel (0), idle_handler_id (-1), being_handled (false) {}
                void add (Type t) {
                        pending = Type (pending | t);
                }
        };
 
        VisualChange pending_visual_change;
        bool visual_change_queued;
 
        static int _idle_visual_changer (void* arg);
        int idle_visual_changer ();
        void ensure_visual_change_idle_handler ();
        virtual void visual_changer (const VisualChange&) = 0;
 
        sigc::connection autoscroll_connection;
        bool autoscroll_horizontal_allowed;
        bool autoscroll_vertical_allowed;
        uint32_t autoscroll_cnt;
        ArdourCanvas::Rect autoscroll_boundary;
 
        PBD::ScopedConnectionList parameter_connections;
        virtual void parameter_changed (std::string);
        virtual void ui_parameter_changed (std::string);
 
        ArdourWidgets::ArdourDropdown   zoom_focus_selector;
        std::vector<std::string> zoom_focus_strings;
        virtual void build_zoom_focus_menu () = 0;
 
        bool _mouse_changed_selection;
        ArdourMarker* entered_marker;
        TimeAxisView* entered_track;
        RegionView* entered_regionview;
 
        bool clear_entered_track;
 
        ARDOUR::Location* transport_loop_location();
 
        std::vector<ArdourCanvas::Ruler::Mark> grid_marks;
        std::unique_ptr<GridLines> grid_lines;
        ArdourCanvas::Container* time_line_group;
 
        void drop_grid ();
        void hide_grid_lines ();
        void maybe_draw_grid_lines (ArdourCanvas::Container*);
 
        virtual void metric_get_timecode (std::vector<ArdourCanvas::Ruler::Mark>&, int64_t, int64_t, gint) {}
        virtual void metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>&, int64_t, int64_t, gint) {}
        virtual void metric_get_samples (std::vector<ArdourCanvas::Ruler::Mark>&, int64_t, int64_t, gint) {}
 
        enum MinsecRulerScale {
                minsec_show_msecs,
                minsec_show_seconds,
                minsec_show_minutes,
                minsec_show_hours,
                minsec_show_many_hours
        };
 
        MinsecRulerScale minsec_ruler_scale;
 
        samplecnt_t minsec_mark_interval;
        gint minsec_mark_modulo;
        gint minsec_nmarks;
 
        void metric_get_minsec (std::vector<ArdourCanvas::Ruler::Mark>&, int64_t, int64_t, gint);
        void set_minsec_ruler_scale (samplepos_t lower, samplepos_t upper);
        void sample_to_clock_parts (samplepos_t sample,
                                    samplepos_t sample_rate,
                                    long*       hrs_p,
                                    long*       mins_p,
                                    long*       secs_p,
                                    long*       millisecs_p);
 
        virtual void set_entered_track (TimeAxisView*) {};
 
        virtual std::pair<Temporal::timepos_t,Temporal::timepos_t> max_zoom_extent() const = 0;
 
        virtual Temporal::timepos_t _get_preferred_edit_position (Editing::EditIgnoreOption,
                                                                  bool use_context_click,
                                                                  bool from_outside_canvas) = 0;
 
        PBD::ScopedConnection escape_connection;
        virtual void escape () {}
 
        virtual void do_undo (uint32_t n) = 0;
        virtual void do_redo (uint32_t n) = 0;
 
        Glib::RefPtr<Gtk::Action> undo_action;
        Glib::RefPtr<Gtk::Action> redo_action;
        Glib::RefPtr<Gtk::Action> alternate_redo_action;
        Glib::RefPtr<Gtk::Action> alternate_alternate_redo_action;
 
        /* protected helper functions to help with registering actions */
 
        static Glib::RefPtr<Gtk::Action> reg_sens (Glib::RefPtr<Gtk::ActionGroup> group, char const* name, char const* label, sigc::slot<void> slot);
        static Glib::RefPtr<Gtk::ToggleAction> toggle_reg_sens (Glib::RefPtr<Gtk::ActionGroup> group, char const* name, char const* label, sigc::slot<void> slot);
        static Glib::RefPtr<Gtk::RadioAction> radio_reg_sens (Glib::RefPtr<Gtk::ActionGroup> action_group, Gtk::RadioAction::Group& radio_group, char const* name, char const* label, sigc::slot<void> slot);
 
        void center_screen_internal (samplepos_t, float);
 
        virtual void automation_create_point_at_edit_point(bool with_guard_points) {}
        virtual void automation_raise_points () {}
        virtual void automation_lower_points () {};
        virtual void automation_move_points_later () {};
        virtual void automation_move_points_earlier () {};
        virtual void automation_begin_edit () {};
        virtual void automation_end_edit () {};
 
        bool temporary_zoom_focus_change;
        bool _dragging_playhead;
};