remove debug output from last commit
[ardour.git] / gtk2_ardour / editor_canvas.cc
index 46b625407a6bbaaf931498b8ae62bcfee50b3eb3..d9fe6f529fd2186cc1ac1d1c6a31f089c8d876c4 100644 (file)
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id$
 */
 
 #include <libgnomecanvasmm/init.h>
 #include <jack/types.h>
+#include <gtkmm2ext/utils.h>
 
+#include <ardour/audioregion.h>
+
+#include "ardour_ui.h"
 #include "editor.h"
 #include "waveview.h"
 #include "simplerect.h"
 #include "rgb_macros.h"
 #include "utils.h"
 #include "time_axis_view.h"
+#include "audio_time_axis.h"
 
 #include "i18n.h"
 
 using namespace std;
 using namespace sigc;
 using namespace ARDOUR;
+using namespace PBD;
 using namespace Gtk;
 using namespace Glib;
 using namespace Gtkmm2ext;
 using namespace Editing;
 
-/* XXX this is a hack. it ought to be the maximum value of an jack_nframes_t */
+/* XXX this is a hack. it ought to be the maximum value of an nframes_t */
 
 const double max_canvas_coordinate = (double) JACK_MAX_FRAMES;
 
@@ -83,26 +88,30 @@ Editor::initialize_canvas ()
        ArdourCanvas::init ();
        ardour_canvas_type_init ();
 
-       /* adjust sensitivity for "picking" items */
+       /* don't try to center the canvas */
 
-       // GNOME_CANVAS(track_canvas)->close_enough = 2;
+       track_canvas.set_center_scroll_region (false);
+       track_canvas.set_dither         (Gdk::RGB_DITHER_NONE);
 
        track_canvas.signal_event().connect (bind (mem_fun (*this, &Editor::track_canvas_event), (ArdourCanvas::Item*) 0));
        track_canvas.set_name ("EditorMainCanvas");
-       track_canvas.add_events (Gdk::POINTER_MOTION_HINT_MASK);
+       track_canvas.add_events (Gdk::POINTER_MOTION_HINT_MASK|Gdk::SCROLL_MASK);
        track_canvas.signal_leave_notify_event().connect (mem_fun(*this, &Editor::left_track_canvas));
-       
+       track_canvas.set_flags (CAN_FOCUS);
+
        /* set up drag-n-drop */
-       vector<Gtk::TargetEntry> target_table;
+
+       vector<TargetEntry> target_table;
        
-       target_table.push_back (TargetEntry ("STRING"));
+       // Drag-N-Drop from the region list can generate this target
+       target_table.push_back (TargetEntry ("regions"));
+
        target_table.push_back (TargetEntry ("text/plain"));
        target_table.push_back (TargetEntry ("text/uri-list"));
        target_table.push_back (TargetEntry ("application/x-rootwin-drop"));
 
-       // GTK2FIX
-       // track_canvas.drag_dest_set (target_table, DEST_DEFAULT_ALL, GdkDragAction (Gdk::ACTION_COPY|Gdk::ACTION_MOVE));
-       // track_canvas.signal_drag_data_received().connect (mem_fun(*this, &Editor::track_canvas_drag_data_received));
+       track_canvas.drag_dest_set (target_table);
+       track_canvas.signal_drag_data_received().connect (mem_fun(*this, &Editor::track_canvas_drag_data_received));
 
        /* stuff for the verbose canvas cursor */
 
@@ -110,8 +119,7 @@ Editor::initialize_canvas ()
 
        verbose_canvas_cursor = new ArdourCanvas::Text (*track_canvas.root());
        verbose_canvas_cursor->property_font_desc() = font;
-       // GTK2FIX
-       // verbose_canvas_cursor->property_anchor() = GTK_ANCHOR_NW;
+       verbose_canvas_cursor->property_anchor() = ANCHOR_NW;
        verbose_canvas_cursor->property_fill_color_rgba() = color_map[cVerboseCanvasCursor];
        
        verbose_cursor_visible = false;
@@ -120,43 +128,46 @@ Editor::initialize_canvas ()
        
        time_line_group = new ArdourCanvas::Group (*track_canvas.root(), 0.0, 0.0);
        cursor_group = new ArdourCanvas::Group (*track_canvas.root(), 0.0, 0.0);
-       
+
        time_canvas.set_name ("EditorTimeCanvas");
        time_canvas.add_events (Gdk::POINTER_MOTION_HINT_MASK);
+       time_canvas.set_flags (CAN_FOCUS);
+       time_canvas.set_center_scroll_region (false);
+       time_canvas.set_dither          (Gdk::RGB_DITHER_NONE);
        
        meter_group = new ArdourCanvas::Group (*time_canvas.root(), 0.0, 0.0);
-       tempo_group = new ArdourCanvas::Group (*time_canvas.root(), 0.0, 0.0);
+       tempo_group = new ArdourCanvas::Group (*time_canvas.root(), 0.0, timebar_height);
        marker_group = new ArdourCanvas::Group (*time_canvas.root(), 0.0, timebar_height * 2.0);
        range_marker_group = new ArdourCanvas::Group (*time_canvas.root(), 0.0, timebar_height * 3.0);
        transport_marker_group = new ArdourCanvas::Group (*time_canvas.root(), 0.0, timebar_height * 4.0);
        
-       tempo_bar = new ArdourCanvas::SimpleRect (*tempo_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       tempo_bar = new ArdourCanvas::SimpleRect (*tempo_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        tempo_bar->property_fill_color_rgba() = color_map[cTempoBar];
        tempo_bar->property_outline_pixels() = 0;
        
-       meter_bar = new ArdourCanvas::SimpleRect (*meter_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       meter_bar = new ArdourCanvas::SimpleRect (*meter_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        meter_bar->property_fill_color_rgba() = color_map[cMeterBar];
        meter_bar->property_outline_pixels() = 0;
        
-       marker_bar = new ArdourCanvas::SimpleRect (*marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       marker_bar = new ArdourCanvas::SimpleRect (*marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        marker_bar->property_fill_color_rgba() = color_map[cMarkerBar];
        marker_bar->property_outline_pixels() = 0;
        
-       range_marker_bar = new ArdourCanvas::SimpleRect (*range_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       range_marker_bar = new ArdourCanvas::SimpleRect (*range_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        range_marker_bar->property_fill_color_rgba() = color_map[cRangeMarkerBar];
        range_marker_bar->property_outline_pixels() = 0;
        
-       transport_marker_bar = new ArdourCanvas::SimpleRect (*transport_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       transport_marker_bar = new ArdourCanvas::SimpleRect (*transport_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        transport_marker_bar->property_fill_color_rgba() = color_map[cTransportMarkerBar];
        transport_marker_bar->property_outline_pixels() = 0;
        
-       range_bar_drag_rect = new ArdourCanvas::SimpleRect (*range_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       range_bar_drag_rect = new ArdourCanvas::SimpleRect (*range_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        range_bar_drag_rect->property_fill_color_rgba() = color_map[cRangeDragBarRectFill];
        range_bar_drag_rect->property_outline_color_rgba() = color_map[cRangeDragBarRect];
        range_bar_drag_rect->property_outline_pixels() = 0;
        range_bar_drag_rect->hide ();
        
-       transport_bar_drag_rect = new ArdourCanvas::SimpleRect (*transport_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height);
+       transport_bar_drag_rect = new ArdourCanvas::SimpleRect (*transport_marker_group, 0.0, 0.0, max_canvas_coordinate, timebar_height-1.0);
        transport_bar_drag_rect ->property_fill_color_rgba() = color_map[cTransportDragRectFill];
        transport_bar_drag_rect->property_outline_color_rgba() = color_map[cTransportDragRect];
        transport_bar_drag_rect->property_outline_pixels() = 0;
@@ -252,120 +263,466 @@ Editor::initialize_canvas ()
        double time_width = FLT_MAX/frames_per_unit;
        time_canvas.set_scroll_region(0.0, 0.0, time_width, time_height);
        
-       edit_cursor = new Cursor (*this, "blue", &Editor::canvas_edit_cursor_event);
-       playhead_cursor = new Cursor (*this, "red", &Editor::canvas_playhead_cursor_event);
-       
+       if (!color_map[cEditCursor]) {
+                warning << _("edit cursor color not defined, check your ardour.colors file!") << endmsg;
+               color_map[cEditCursor] = RGBA_TO_UINT (30,30,30,255);
+       }
+
+       if (!color_map[cPlayHead]) {
+               warning << _("playhead color not defined, check your ardour.colors file!") << endmsg;
+               color_map[cPlayHead] = RGBA_TO_UINT (0,0,0,255);
+       }
+
+       edit_cursor = new Cursor (*this, &Editor::canvas_edit_cursor_event);
+       edit_cursor->canvas_item.property_fill_color_rgba() = color_map[cEditCursor];
+       playhead_cursor = new Cursor (*this, &Editor::canvas_playhead_cursor_event);
+       playhead_cursor->canvas_item.property_fill_color_rgba() = color_map[cPlayHead];
+
+       initial_ruler_update_required = true;
        track_canvas.signal_size_allocate().connect (mem_fun(*this, &Editor::track_canvas_allocate));
+
 }
 
 void
-Editor::reset_scrolling_region (Gtk::Allocation* alloc)
+Editor::track_canvas_allocate (Gtk::Allocation alloc)
 {
-       guint32 last_canvas_unit;
-       double height;
-       guint32 canvas_alloc_height, canvas_alloc_width;
-       TrackViewList::iterator i;
-       static bool first_time = true;
-
-       /* We need to make sure that the canvas always has its
-          scrolling region set to larger of:
-
-          - the size allocated for it (within the container its packed in)
-          - the size required to see the entire session
-
-          If we don't ensure at least the first of these, the canvas
-          does some wierd and in my view unnecessary stuff to center
-          itself within the allocated area, which causes bad, bad
-          results.
-          
-          XXX GnomeCanvas has fixed this, and has an option to
-          control the centering behaviour.
-       */
+       canvas_allocation = alloc;
 
-       last_canvas_unit = (guint32) ceil ((float) max_frames / frames_per_unit);
+       if (!initial_ruler_update_required) {
+               if (!canvas_idle_queued) {
+                       /* call this first so that we do stuff before any pending redraw */
+                       Glib::signal_idle().connect (mem_fun (*this, &Editor::track_canvas_size_allocated), false);
+                       canvas_idle_queued = true;
+               }
+               return;
+       } 
 
-       height = 0;
+       initial_ruler_update_required = false;
+       
+       track_canvas_size_allocated ();
+}
+
+bool
+Editor::track_canvas_size_allocated ()
+{
+       if (canvas_idle_queued) {
+               canvas_idle_queued = false;
+       }
+
+       canvas_width = canvas_allocation.get_width();
+       canvas_height = canvas_allocation.get_height();
+
+       full_canvas_height = canvas_height;
 
        if (session) {
+               TrackViewList::iterator i;
+               double height = 0;
+
                for (i = track_views.begin(); i != track_views.end(); ++i) {
                        if ((*i)->control_parent) {
                                height += (*i)->effective_height;
-                               height += track_spacing;
                        }
                }
                
-               if (height) {
-                       height -= track_spacing;
-               }
+               full_canvas_height = height;
        }
 
-       canvas_height = (guint32) height;
-       
-       if (alloc) {
-               canvas_alloc_height = alloc->get_height();
-               canvas_alloc_width = alloc->get_width();
-       } else {
-               canvas_alloc_height = track_canvas.get_height();
-               canvas_alloc_width = track_canvas.get_width();
-       }
+       zoom_range_clock.set ((nframes_t) floor ((canvas_width * frames_per_unit)));
+       edit_cursor->set_position (edit_cursor->current_frame);
+       playhead_cursor->set_position (playhead_cursor->current_frame);
 
-       canvas_height = max (canvas_height, canvas_alloc_height);
-       track_canvas.set_scroll_region ( 0.0, 0.0, max (last_canvas_unit, canvas_alloc_width), canvas_height);
+       reset_hscrollbar_stepping ();
+       reset_scrolling_region ();
 
-       if (edit_cursor) edit_cursor->set_length (canvas_alloc_height);
-       if (playhead_cursor) playhead_cursor->set_length (canvas_alloc_height);
+       if (edit_cursor) edit_cursor->set_length (canvas_height);
+       if (playhead_cursor) playhead_cursor->set_length (canvas_height);
 
        if (marker_drag_line) {
-               marker_drag_line_points.back().set_x(canvas_height);
-               // cerr << "set mlA points, nc = " << marker_drag_line_points.num_points << endl;
+               marker_drag_line_points.back().set_y(canvas_height);
                marker_drag_line->property_points() = marker_drag_line_points;
        }
+
        if (range_marker_drag_rect) {
                range_marker_drag_rect->property_y1() = 0.0;
-               range_marker_drag_rect->property_y2() = (double) canvas_height;
+               range_marker_drag_rect->property_y2() = canvas_height;
        }
 
        if (transport_loop_range_rect) {
                transport_loop_range_rect->property_y1() = 0.0;
-               transport_loop_range_rect->property_y2() = (double) canvas_height;
+               transport_loop_range_rect->property_y2() = canvas_height;
        }
 
        if (transport_punch_range_rect) {
                transport_punch_range_rect->property_y1() = 0.0;
-               transport_punch_range_rect->property_y2() = (double) canvas_height;
+               transport_punch_range_rect->property_y2() = canvas_height;
        }
 
        if (transport_punchin_line) {
                transport_punchin_line->property_y1() = 0.0;
-               transport_punchin_line->property_y2() = (double) canvas_height;
+               transport_punchin_line->property_y2() = canvas_height;
        }
 
        if (transport_punchout_line) {
                transport_punchout_line->property_y1() = 0.0;
-               transport_punchout_line->property_y2() = (double) canvas_height;
+               transport_punchout_line->property_y2() = canvas_height;
        }
                
-       update_fixed_rulers ();
+       update_fixed_rulers();
+       tempo_map_changed (Change (0), true);
+       
+       Resized (); /* EMIT_SIGNAL */
 
-       if (is_visible() && first_time) {
-               tempo_map_changed (Change (0));
-               first_time = false;
-       } else {
-               redisplay_tempo ();
+       return false;
+}
+
+void
+Editor::reset_scrolling_region (Gtk::Allocation* alloc)
+{
+       TreeModel::Children rows = route_display_model->children();
+       TreeModel::Children::iterator i;
+       double pos;
+
+        for (pos = 0, i = rows.begin(); i != rows.end(); ++i) {
+               TimeAxisView *tv = (*i)[route_display_columns.tv];
+               if (tv != 0 && !tv->hidden()) {
+                       pos += tv->effective_height;
+               }
+       }
+
+       double last_canvas_unit =  last_canvas_frame / frames_per_unit;
+
+       track_canvas.set_scroll_region (0.0, 0.0, max (last_canvas_unit, canvas_width), pos);
+
+       // XXX what is the correct height value for the time canvas ? this overstates it
+       time_canvas.set_scroll_region ( 0.0, 0.0, max (last_canvas_unit, canvas_width), canvas_height);
+
+       controls_layout.queue_resize();
+}
+
+void
+Editor::controls_layout_size_request (Requisition* req)
+{
+       TreeModel::Children rows = route_display_model->children();
+       TreeModel::Children::iterator i;
+       double pos;
+
+        for (pos = 0, i = rows.begin(); i != rows.end(); ++i) {
+               TimeAxisView *tv = (*i)[route_display_columns.tv];
+               if (tv != 0) {
+                       pos += tv->effective_height;
+               }
        }
+
+       RefPtr<Gdk::Screen> screen = get_screen();
+
+       if (!screen) {
+               screen = Gdk::Screen::get_default();
+       }
+
+       /* never let the width of the controls area shrink horizontally */
+
+       edit_controls_vbox.check_resize();
+
+       req->width = max (edit_controls_vbox.get_width(),  controls_layout.get_width());
+       
+       /* don't get too big. the fudge factors here are just guesses */
+       
+       req->width = min (req->width, screen->get_width() - 300);
+       req->height = min ((gint) pos, (screen->get_height() - 400));
+
+       /* this one is important: it determines how big the layout thinks it really is, as 
+          opposed to what it displays on the screen
+       */
+
+       controls_layout.set_size (req->width, (gint) pos);
 }
 
 bool
 Editor::track_canvas_map_handler (GdkEventAny* ev)
 {
-       track_canvas_scroller.get_window()->set_cursor (*current_canvas_cursor);
+       track_canvas.get_window()->set_cursor (*current_canvas_cursor);
        return false;
 }
 
 bool
 Editor::time_canvas_map_handler (GdkEventAny* ev)
 {
-       time_canvas_scroller.get_window()->set_cursor (*timebar_cursor);
+       time_canvas.get_window()->set_cursor (*timebar_cursor);
        return false;
 }
 
+void  
+Editor::track_canvas_drag_data_received (const RefPtr<Gdk::DragContext>& context,
+                                        int x, int y, 
+                                        const SelectionData& data,
+                                        guint info, guint time)
+{
+       if (data.get_target() == "regions") {
+               drop_regions (context, x, y, data, info, time);
+       } else {
+               drop_paths (context, x, y, data, info, time);
+       }
+}
+
+void
+Editor::drop_paths (const RefPtr<Gdk::DragContext>& context,
+                   int x, int y, 
+                   const SelectionData& data,
+                   guint info, guint time)
+{
+       TimeAxisView* tvp;
+       AudioTimeAxisView* tv;
+       double cy;
+       vector<ustring> paths;
+       string spath;
+       GdkEvent ev;
+       nframes_t frame;
+
+       if (convert_drop_to_paths (paths, context, x, y, data, info, time)) {
+               goto out;
+       }
+
+       /* D-n-D coordinates are window-relative, so convert to "world" coordinates
+        */
+
+       double wx;
+       double wy;
+
+       track_canvas.window_to_world (x, y, wx, wy);
+       wx += horizontal_adjustment.get_value();
+       wy += vertical_adjustment.get_value();
+       
+       ev.type = GDK_BUTTON_RELEASE;
+       ev.button.x = wx;
+       ev.button.y = wy;
+
+       frame = event_frame (&ev, 0, &cy);
+
+       snap_to (frame);
+
+       if ((tvp = trackview_by_y_position (cy)) == 0) {
+
+               /* drop onto canvas background: create new tracks */
+
+               nframes_t pos = 0;
+               do_embed (paths, false, ImportAsTrack, 0, pos, false);
+               
+       } else if ((tv = dynamic_cast<AudioTimeAxisView*>(tvp)) != 0) {
+
+               /* check that its an audio track, not a bus */
+               
+               if (tv->get_diskstream()) {
+                       do_embed (paths, false, ImportToTrack, tv->audio_track(), frame, true);
+               }
+       }
+
+  out:
+       context->drag_finish (true, false, time);
+}
+
+void
+Editor::drop_regions (const RefPtr<Gdk::DragContext>& context,
+                     int x, int y, 
+                     const SelectionData& data,
+                     guint info, guint time)
+{
+       const SerializedObjectPointers<boost::shared_ptr<Region> >* sr = 
+               reinterpret_cast<const SerializedObjectPointers<boost::shared_ptr<Region> > *> (data.get_data());
+
+       for (uint32_t i = 0; i < sr->cnt; ++i) {
+
+               boost::shared_ptr<Region> r = sr->data[i];
+               boost::shared_ptr<AudioRegion> ar;
+
+               if ((ar = boost::dynamic_pointer_cast<AudioRegion>(r)) != 0) {
+                       insert_region_list_drag (ar, x, y);
+               }
+       }
+
+       context->drag_finish (true, false, time);
+}
+
+void
+Editor::maybe_autoscroll (GdkEvent* event)
+{
+       nframes_t rightmost_frame = leftmost_frame + current_page_frames();
+       nframes_t frame = drag_info.current_pointer_frame;
+       bool startit = false;
+
+       static int last_autoscroll_direction = 0;
+
+       if (frame > rightmost_frame) {
+
+               if (rightmost_frame < max_frames) {
+                       autoscroll_direction = 1;
+                       startit = true;
+               }
+
+       } else if (frame < leftmost_frame) {
+
+               if (leftmost_frame > 0) {
+                       autoscroll_direction = -1;
+                       startit = true;
+               }
+
+       } else {
+
+               if (drag_info.last_pointer_frame > drag_info.current_pointer_frame) {
+                       autoscroll_direction = -1;
+               } else {
+                       autoscroll_direction = 1;
+               }
+       }
+
+
+       if ((autoscroll_direction != last_autoscroll_direction) || (leftmost_frame < frame < rightmost_frame)) {
+               stop_canvas_autoscroll ();
+       }
+       
+       if (startit && autoscroll_timeout_tag < 0) {
+               start_canvas_autoscroll (autoscroll_direction);
+       }
+
+       last_autoscroll_direction = autoscroll_direction;
+}
+
+gint
+Editor::_autoscroll_canvas (void *arg)
+{
+        return ((Editor *) arg)->autoscroll_canvas ();
+}
+
+bool
+Editor::autoscroll_canvas ()
+{
+       nframes_t new_frame;
+       nframes_t limit = max_frames - current_page_frames();
+       GdkEventMotion ev;
+       nframes_t target_frame;
+
+       if (autoscroll_direction < 0) {
+               if (leftmost_frame < autoscroll_distance) {
+                       new_frame = 0;
+               } else {
+                       new_frame = leftmost_frame - autoscroll_distance;
+               }
+               target_frame = drag_info.current_pointer_frame - autoscroll_distance;
+       } else {
+               if (leftmost_frame > limit - autoscroll_distance) {
+                       new_frame = limit;
+               } else {
+                       new_frame = leftmost_frame + autoscroll_distance;
+               }
+               target_frame = drag_info.current_pointer_frame + autoscroll_distance;
+       }
+
+       /* now fake a motion event to get the object that is being dragged to move too */
+
+       ev.type = GDK_MOTION_NOTIFY;
+       ev.state &= Gdk::BUTTON1_MASK;
+       ev.x = frame_to_unit (target_frame);
+       ev.y = drag_info.current_pointer_y;
+       motion_handler (drag_info.item, (GdkEvent*) &ev, drag_info.item_type, true);
+
+       if (new_frame == 0 || new_frame == limit) {
+               /* we are done */
+               return false;
+       }
+
+       autoscroll_cnt++;
+
+       if (autoscroll_cnt == 1) {
+
+               /* connect the timeout so that we get called repeatedly */
+
+               autoscroll_timeout_tag = g_idle_add ( _autoscroll_canvas, this);
+               return false;
+
+       } 
+
+       if (new_frame != leftmost_frame) {
+               reset_x_origin (new_frame);
+       }
+
+       if (autoscroll_cnt == 50) { /* 0.5 seconds */
+               
+               /* after about a while, speed up a bit by changing the timeout interval */
+
+               autoscroll_distance = (nframes_t) floor (current_page_frames()/30.0f);
+               
+       } else if (autoscroll_cnt == 150) { /* 1.0 seconds */
+
+               autoscroll_distance = (nframes_t) floor (current_page_frames()/20.0f);
+
+       } else if (autoscroll_cnt == 300) { /* 1.5 seconds */
+
+               /* after about another while, speed up by increasing the shift per callback */
+
+               autoscroll_distance =  (nframes_t) floor (current_page_frames()/10.0f);
+
+       } 
+
+       return true;
+}
+
+void
+Editor::start_canvas_autoscroll (int dir)
+{
+       if (!session || autoscroll_active) {
+               return;
+       }
+
+       stop_canvas_autoscroll ();
+
+       autoscroll_active = true;
+       autoscroll_direction = dir;
+       autoscroll_distance = (nframes_t) floor (current_page_frames()/50.0);
+       autoscroll_cnt = 0;
+       
+       /* do it right now, which will start the repeated callbacks */
+
+       autoscroll_canvas ();
+}
+
+void
+Editor::stop_canvas_autoscroll ()
+{
+       if (autoscroll_timeout_tag >= 0) {
+               g_source_remove (autoscroll_timeout_tag);
+               autoscroll_timeout_tag = -1;
+       }
+
+       autoscroll_active = false;
+}
+
+gint
+Editor::left_track_canvas (GdkEventCrossing *ev)
+{
+       set_entered_track (0);
+       set_entered_regionview (0);
+       return FALSE;
+}
+
+
+void 
+Editor::canvas_horizontally_scrolled ()
+{
+       /* this is the core function that controls horizontal scrolling of the canvas. it is called
+          whenever the horizontal_adjustment emits its "value_changed" signal. it typically executes in an
+          idle handler, which is important because tempo_map_changed() should issue redraws immediately
+          and not defer them to an idle handler.
+       */
+
+       leftmost_frame = (nframes_t) floor (horizontal_adjustment.get_value() * frames_per_unit);
+       nframes_t rightmost_frame = leftmost_frame + current_page_frames ();
+       
+       if (rightmost_frame > last_canvas_frame) {
+               last_canvas_frame = rightmost_frame;
+               reset_scrolling_region ();
+       }
+       
+       update_fixed_rulers ();
+
+       tempo_map_changed (Change (0), !_dragging_hscrollbar);
+}
+