many pervasive changes primarily related to waveform drawing, particular content-dragging, colors, and more

22 files changed, 389 insertions, 274 deletions

diff --git a/gtk2_ardour/audio_region_view.cc b/gtk2_ardour/audio_region_view.cc
index 68bd462eb5..7a509cd1d8 100644
--- a/gtk2_ardour/audio_region_view.cc
+++ b/gtk2_ardour/audio_region_view.cc
@@ -42,6 +42,7 @@
 #include "canvas/poly_line.h"
 #include "canvas/line.h"
 #include "canvas/text.h"
+#include "canvas/debug.h"
 
 #include "streamview.h"
 #include "audio_region_view.h"
@@ -158,21 +159,25 @@ AudioRegionView::init (Gdk::Color const & basic_color, bool wfd)
 	create_waves ();
 
 	fade_in_shape = new ArdourCanvas::Polygon (group);
+	CANVAS_DEBUG_NAME (fade_in_shape, string_compose ("fade in shape for %1", region()->name()));
 	fade_in_shape->set_fill_color (fade_color);
 	fade_in_shape->set_data ("regionview", this);
 
 	fade_out_shape = new ArdourCanvas::Polygon (group);
+	CANVAS_DEBUG_NAME (fade_out_shape, string_compose ("fade out shape for %1", region()->name()));
 	fade_out_shape->set_fill_color (fade_color);
 	fade_out_shape->set_data ("regionview", this);
 
 	if (!_recregion) {
 		fade_in_handle = new ArdourCanvas::Rectangle (group);
+		CANVAS_DEBUG_NAME (fade_in_handle, string_compose ("fade in handle for %1", region()->name()));
 		fade_in_handle->set_fill_color (UINT_RGBA_CHANGE_A (fill_color, 0));
 		fade_in_handle->set_outline_color (RGBA_TO_UINT (0, 0, 0, 0));
 
 		fade_in_handle->set_data ("regionview", this);
 
 		fade_out_handle = new ArdourCanvas::Rectangle (group);
+		CANVAS_DEBUG_NAME (fade_out_handle, string_compose ("fade out handle for %1", region()->name()));
 		fade_out_handle->set_fill_color (UINT_RGBA_CHANGE_A (fill_color, 0));
 		fade_out_handle->set_outline_color (RGBA_TO_UINT (0, 0, 0, 0));
 
@@ -229,6 +234,9 @@ AudioRegionView::init (Gdk::Color const & basic_color, bool wfd)
 	setup_waveform_shape ();
 	setup_waveform_scale ();
 
+	frame_handle_start->raise_to_top ();
+	frame_handle_end->raise_to_top ();
+
 	/* XXX sync mark drag? */
 }
 
@@ -360,10 +368,9 @@ AudioRegionView::region_resized (const PropertyChange& what_changed)
 	interesting_stuff.add (ARDOUR::Properties::length);
 
 	if (what_changed.contains (interesting_stuff)) {
-
+		
 		for (uint32_t n = 0; n < waves.size(); ++n) {
 			waves[n]->region_resized ();
-			waves[n]->set_region_start (region()->start ());
 		}
 
 		for (vector<GhostRegion*>::iterator i = ghosts.begin(); i != ghosts.end(); ++i) {
@@ -371,7 +378,6 @@ AudioRegionView::region_resized (const PropertyChange& what_changed)
 
 				for (vector<WaveView*>::iterator w = agr->waves.begin(); w != agr->waves.end(); ++w) {
 					(*w)->region_resized ();
-					(*w)->set_region_start (region()->start ());
 				}
 			}
 		}
@@ -432,14 +438,7 @@ void
 AudioRegionView::region_muted ()
 {
 	RegionView::region_muted();
-
-	for (uint32_t n=0; n < waves.size(); ++n) {
-		if (_region->muted()) {
-			waves[n]->set_outline_color (UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_WaveForm(), MUTED_ALPHA));
-		} else {
-			waves[n]->set_outline_color (ARDOUR_UI::config()->get_canvasvar_WaveForm());
-		}
-	}
+	set_waveform_colors ();
 }
 
 void
@@ -750,12 +749,14 @@ AudioRegionView::redraw_start_xfade_to (boost::shared_ptr<AudioRegion> ar, frame
 
 	if (!start_xfade_in) {
 		start_xfade_in = new ArdourCanvas::PolyLine (group);
+		CANVAS_DEBUG_NAME (start_xfade_in, string_compose ("xfade start in line for %1", region()->name()));
 		start_xfade_in->set_outline_color (ARDOUR_UI::config()->get_canvasvar_CrossfadeLine());
 		start_xfade_in->set_outline_width (1.5);
 	}
 
 	if (!start_xfade_out) {
 		start_xfade_out = new ArdourCanvas::PolyLine (group);
+		CANVAS_DEBUG_NAME (start_xfade_out, string_compose ("xfade start out line for %1", region()->name()));
 		uint32_t col = UINT_RGBA_CHANGE_A (ARDOUR_UI::config()->get_canvasvar_CrossfadeLine(), 128);
 		start_xfade_out->set_outline_color (col);
 		start_xfade_out->set_outline_width (2.0);
@@ -763,6 +764,7 @@ AudioRegionView::redraw_start_xfade_to (boost::shared_ptr<AudioRegion> ar, frame
 
 	if (!start_xfade_rect) {
 		start_xfade_rect = new ArdourCanvas::Rectangle (group);
+		CANVAS_DEBUG_NAME (start_xfade_rect, string_compose ("xfade start rect for %1", region()->name()));
 		start_xfade_rect->set_fill (true);
 		start_xfade_rect->set_fill_color (ARDOUR_UI::config()->get_canvasvar_ActiveCrossfade());
 		start_xfade_rect->set_outline (false);
@@ -775,7 +777,6 @@ AudioRegionView::redraw_start_xfade_to (boost::shared_ptr<AudioRegion> ar, frame
 
 	start_xfade_in->set (points);
 	start_xfade_in->show ();
-	start_xfade_in->raise_to_top ();
 
 	/* fade out line */
 
@@ -807,9 +808,6 @@ AudioRegionView::redraw_start_xfade_to (boost::shared_ptr<AudioRegion> ar, frame
 
 	start_xfade_out->set (ipoints);
 	start_xfade_out->show ();
-	start_xfade_out->raise_to_top ();
-
-	start_xfade_rect->raise_to_top ();  //this needs to be topmost so the lines don't steal mouse focus
 
 	show_start_xfade();
 }
@@ -837,6 +835,7 @@ AudioRegionView::redraw_end_xfade_to (boost::shared_ptr<AudioRegion> ar, framecn
 
 	if (!end_xfade_in) {
 		end_xfade_in = new ArdourCanvas::PolyLine (group);
+		CANVAS_DEBUG_NAME (end_xfade_in, string_compose ("xfade end in line for %1", region()->name()));
 		uint32_t col UINT_RGBA_CHANGE_A (ARDOUR_UI::config()->get_canvasvar_CrossfadeLine(), 128);
 		end_xfade_in->set_outline_color (col);
 		end_xfade_in->set_outline_width (1.5);
@@ -844,12 +843,14 @@ AudioRegionView::redraw_end_xfade_to (boost::shared_ptr<AudioRegion> ar, framecn
 
 	if (!end_xfade_out) {
 		end_xfade_out = new ArdourCanvas::PolyLine (group);
+		CANVAS_DEBUG_NAME (end_xfade_out, string_compose ("xfade end out line for %1", region()->name()));
 		end_xfade_out->set_outline_color (ARDOUR_UI::config()->get_canvasvar_CrossfadeLine());
 		end_xfade_out->set_outline_width (2.0);
 	}
 
 	if (!end_xfade_rect) {
 		end_xfade_rect = new ArdourCanvas::Rectangle (group);
+		CANVAS_DEBUG_NAME (end_xfade_rect, string_compose ("xfade end rect for %1", region()->name()));
 		end_xfade_rect->set_fill (true);
 		end_xfade_rect->set_fill_color (ARDOUR_UI::config()->get_canvasvar_ActiveCrossfade());
 		end_xfade_rect->set_outline (0);
@@ -1025,16 +1026,7 @@ AudioRegionView::set_colors ()
 					   ARDOUR_UI::config()->get_canvasvar_GainLineInactive());
 	}
 
-	for (uint32_t n=0; n < waves.size(); ++n) {
-		if (_region->muted()) {
-			waves[n]->set_outline_color (UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_WaveForm(), MUTED_ALPHA));
-		} else {
-			waves[n]->set_outline_color (ARDOUR_UI::config()->get_canvasvar_WaveForm());
-		}
-
-		waves[n]->set_clip_color (ARDOUR_UI::config()->get_canvasvar_WaveFormClip());
-		waves[n]->set_zero_color (ARDOUR_UI::config()->get_canvasvar_ZeroLine());
-	}
+	set_waveform_colors ();
 
 	if (start_xfade_in) {
 		start_xfade_in->set_outline_color (ARDOUR_UI::config()->get_canvasvar_CrossfadeLine());
@@ -1181,9 +1173,10 @@ AudioRegionView::create_one_wave (uint32_t which, bool /*direct*/)
 	gdouble yoff = which * ht;
 
 	WaveView *wave = new WaveView (group, audio_region ());
-
+	CANVAS_DEBUG_NAME (wave, string_compose ("wave view for chn %1 of %2", which, get_item_name()));
+	
+	wave->lower_to_bottom ();
 	wave->set_channel (which);
-	wave->set_x_position (0);
 	wave->set_y_position (yoff);
 	wave->set_height (ht);
 	wave->set_samples_per_pixel (samples_per_pixel);
@@ -1201,8 +1194,6 @@ AudioRegionView::create_one_wave (uint32_t which, bool /*direct*/)
 	// CAIROCANVAS
 	// wave->property_zero_line() = true;
 
-	wave->set_region_start (_region->start());
-
 	switch (Config->get_waveform_shape()) {
 	case Rectified:
 		wave->set_shape (WaveView::Rectified);
@@ -1362,12 +1353,11 @@ AudioRegionView::add_ghost (TimeAxisView& tv)
 		}
 
 		WaveView *wave = new WaveView (ghost->group, audio_region());
+		CANVAS_DEBUG_NAME (wave, string_compose ("ghost wave for %1", get_item_name()));
 
 		wave->set_channel (n);
-		wave->set_x_position (0);
 		wave->set_samples_per_pixel (samples_per_pixel);
 		wave->set_amplitude_above_axis (_amplitude_above_axis);
-		wave->set_region_start (_region->start());
 
 		ghost->waves.push_back(wave);
 	}
@@ -1442,54 +1432,62 @@ AudioRegionView::color_handler ()
 }
 
 void
-AudioRegionView::set_frame_color ()
+AudioRegionView::set_waveform_colors ()
 {
-	if (!frame) {
-		return;
-	}
-
-	if (_region->opaque()) {
-		fill_opacity = 130;
-	} else {
-		fill_opacity = 0;
-	}
-
-	TimeAxisViewItem::set_frame_color ();
-
-        uint32_t wc;
-        uint32_t fc;
-
+	ArdourCanvas::Color fill, outline, clip, zero;
+	
 	if (_selected) {
                 if (_region->muted()) {
-                        wc = UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_SelectedWaveForm(), MUTED_ALPHA);
+                        outline = UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_SelectedWaveForm(), MUTED_ALPHA);
                 } else {
-                        wc = ARDOUR_UI::config()->get_canvasvar_SelectedWaveForm();
+                        outline = ARDOUR_UI::config()->get_canvasvar_SelectedWaveForm();
                 }
-                fc = ARDOUR_UI::config()->get_canvasvar_SelectedWaveFormFill();
+                fill = ARDOUR_UI::config()->get_canvasvar_SelectedWaveFormFill();
 	} else {
 		if (_recregion) {
                         if (_region->muted()) {
-                                wc = UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_RecWaveForm(), MUTED_ALPHA);
+                                outline = UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_RecWaveForm(), MUTED_ALPHA);
                         } else {
-                                wc = ARDOUR_UI::config()->get_canvasvar_RecWaveForm();
+                                outline = ARDOUR_UI::config()->get_canvasvar_RecWaveForm();
                         }
-                        fc = ARDOUR_UI::config()->get_canvasvar_RecWaveFormFill();
+                        fill = ARDOUR_UI::config()->get_canvasvar_RecWaveFormFill();
 		} else {
                         if (_region->muted()) {
-                                wc = UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_WaveForm(), MUTED_ALPHA);
+                                outline = UINT_RGBA_CHANGE_A(ARDOUR_UI::config()->get_canvasvar_WaveForm(), MUTED_ALPHA);
                         } else {
-                                wc = ARDOUR_UI::config()->get_canvasvar_WaveForm();
+                                outline = ARDOUR_UI::config()->get_canvasvar_WaveForm();
                         }
-                        fc = ARDOUR_UI::config()->get_canvasvar_WaveFormFill();
+                        fill = ARDOUR_UI::config()->get_canvasvar_WaveFormFill();
 		}
 	}
 
+	clip = ARDOUR_UI::config()->get_canvasvar_WaveFormClip();
+	zero = ARDOUR_UI::config()->get_canvasvar_ZeroLine();
+
         for (vector<ArdourCanvas::WaveView*>::iterator w = waves.begin(); w != waves.end(); ++w) {
-		(*w)->set_outline_color (wc);
-                if (!_region->muted()) {
-                        (*w)->set_fill_color (fc);
-                }
-        }
+		(*w)->set_outline_color (outline);
+		(*w)->set_fill_color (fill);
+		(*w)->set_clip_color (clip);
+		(*w)->set_zero_color (zero);
+	}
+}
+
+void
+AudioRegionView::set_frame_color ()
+{
+	if (!frame) {
+		return;
+	}
+
+	if (_region->opaque()) {
+		fill_opacity = 130;
+	} else {
+		fill_opacity = 0;
+	}
+
+	TimeAxisViewItem::set_frame_color ();
+
+	set_waveform_colors ();
 }
 
 void
@@ -1555,6 +1553,7 @@ AudioRegionView::transients_changed ()
 	while (feature_lines.size() < analysis_features.size()) {
 
 		ArdourCanvas::Line* canvas_item = new ArdourCanvas::Line(group);
+		CANVAS_DEBUG_NAME (canvas_item, string_compose ("transient group for %1", region()->name()));
 
 		canvas_item->set (ArdourCanvas::Duple (-1.0, 2.0),
 				  ArdourCanvas::Duple (1.0, _height - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE - 1));
diff --git a/gtk2_ardour/audio_region_view.h b/gtk2_ardour/audio_region_view.h
index 719dfc2b55..049b61a571 100644
--- a/gtk2_ardour/audio_region_view.h
+++ b/gtk2_ardour/audio_region_view.h
@@ -189,6 +189,7 @@ class AudioRegionView : public RegionView
 	void peaks_ready_handler (uint32_t);
 
 	void set_colors ();
+        void set_waveform_colors ();
 	void compute_colors (Gdk::Color const &);
 	void reset_width_dependent_items (double pixel_width);
 	void set_frame_color ();
diff --git a/gtk2_ardour/crossfade_edit.cc b/gtk2_ardour/crossfade_edit.cc
index 5d6e0d465d..214ba7fb06 100644
--- a/gtk2_ardour/crossfade_edit.cc
+++ b/gtk2_ardour/crossfade_edit.cc
@@ -1172,9 +1172,7 @@ CrossfadeEditor::make_waves (boost::shared_ptr<AudioRegion> region, WhichFade wh
 			waveview->set_outline_color (color);
 			waveview->set_fill_color (color);
 
-			if (which == In) {
-				waveview->set_region_start (region->start());
-			} else {
+			if (which != In) {
 				waveview->set_region_start (region->start() + region->length() - xfade->length());
 			}
 
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index d458b41b84..3f06a5b87b 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -3731,7 +3731,7 @@ Editor::set_show_measures (bool yn)
 			
 			compute_current_bbt_points (leftmost_frame, leftmost_frame + current_page_samples(), begin, end);
 			draw_measures (begin, end);
-		}
+		} 
 
 		instant_save ();
 	}
diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 35a7e930ef..3dbb48ce43 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -1830,6 +1830,7 @@ TrimDrag::motion (GdkEvent* event, bool first_move)
 	TimeAxisView* tvp = &_primary->get_time_axis_view ();
 	RouteTimeAxisView* tv = dynamic_cast<RouteTimeAxisView*>(tvp);
 	pair<set<boost::shared_ptr<Playlist> >::iterator,bool> insert_result;
+	frameoffset_t frame_delta = 0;
 
 	if (tv && tv->is_track()) {
 		speed = tv->track()->speed();
@@ -1926,27 +1927,11 @@ TrimDrag::motion (GdkEvent* event, bool first_move)
 
 	case ContentsTrim:
 		{
-			bool swap_direction = false;
-
-			if (event && Keyboard::modifier_state_equals (event->button.state, Keyboard::PrimaryModifier)) {
-				swap_direction = true;
-			}
-
-			framecnt_t frame_delta = 0;
-
-			bool left_direction = false;
-			if (last_pointer_frame() > adjusted_current_frame(event)) {
-				left_direction = true;
-			}
-
-			if (left_direction) {
-				frame_delta = (last_pointer_frame() - adjusted_current_frame(event));
-			} else {
-				frame_delta = (adjusted_current_frame(event) - last_pointer_frame());
-			}
+			frame_delta = (adjusted_current_frame(event) - last_pointer_frame());
+			// frame_delta = (last_pointer_frame() - adjusted_current_frame(event));
 
 			for (list<DraggingView>::const_iterator i = _views.begin(); i != _views.end(); ++i) {
-				i->view->trim_contents (frame_delta, left_direction, swap_direction);
+				i->view->move_contents (frame_delta);
 			}
 		}
 		break;
@@ -1960,7 +1945,7 @@ TrimDrag::motion (GdkEvent* event, bool first_move)
 		show_verbose_cursor_time ((framepos_t) (rv->region()->last_frame() / speed));
 		break;
 	case ContentsTrim:
-		show_verbose_cursor_time (adjusted_current_frame (event));
+		// show_verbose_cursor_time (frame_delta);
 		break;
 	}
 }
diff --git a/gtk2_ardour/editor_tempodisplay.cc b/gtk2_ardour/editor_tempodisplay.cc
index 09d9b39c73..400f427ee5 100644
--- a/gtk2_ardour/editor_tempodisplay.cc
+++ b/gtk2_ardour/editor_tempodisplay.cc
@@ -162,8 +162,9 @@ Editor::compute_current_bbt_points (framepos_t leftmost, framepos_t rightmost,
 void
 Editor::hide_measures ()
 {
-	if (tempo_lines)
+	if (tempo_lines) {
 		tempo_lines->hide();
+	}
 }
 
 void
diff --git a/gtk2_ardour/ghostregion.cc b/gtk2_ardour/ghostregion.cc
index 6801e80d02..5350a0e459 100644
--- a/gtk2_ardour/ghostregion.cc
+++ b/gtk2_ardour/ghostregion.cc
@@ -21,6 +21,8 @@
 #include "canvas/group.h"
 #include "canvas/rectangle.h"
 #include "canvas/wave_view.h"
+#include "canvas/debug.h"
+
 #include "ardour_ui.h"
 #include "automation_time_axis.h"
 #include "ghostregion.h"
@@ -41,9 +43,11 @@ GhostRegion::GhostRegion (ArdourCanvas::Group* parent, TimeAxisView& tv, TimeAxi
 	, source_trackview (source_tv)
 {
 	group = new ArdourCanvas::Group (parent);
+	CANVAS_DEBUG_NAME (group, "ghost region group");
 	group->set_position (ArdourCanvas::Duple (initial_pos, 0));
 
 	base_rect = new ArdourCanvas::Rectangle (group);
+	CANVAS_DEBUG_NAME (base_rect, "ghost region rect");
 	base_rect->set_x0 (0);
 	base_rect->set_y0 (0);
 	base_rect->set_y1 (trackview.current_height());
@@ -191,6 +195,7 @@ MidiGhostRegion::GhostEvent::GhostEvent (NoteBase* e, ArdourCanvas::Group* g)
 	: event (e)
 {
 	rect = new ArdourCanvas::Rectangle (g, ArdourCanvas::Rect (e->x0(), e->y0(), e->x1(), e->y1()));
+	CANVAS_DEBUG_NAME (rect, "ghost note rect");
 }
 
 MidiGhostRegion::GhostEvent::~GhostEvent ()
diff --git a/gtk2_ardour/region_view.cc b/gtk2_ardour/region_view.cc
index 37ddb45917..ac7fe7e8fa 100644
--- a/gtk2_ardour/region_view.cc
+++ b/gtk2_ardour/region_view.cc
@@ -632,9 +632,11 @@ RegionView::region_sync_changed ()
 		/* points set below */
 
 		sync_mark = new ArdourCanvas::Polygon (group);
+		CANVAS_DEBUG_NAME (sync_mark, string_compose ("sync mark for %1", get_item_name()));
 		sync_mark->set_fill_color (RGBA_TO_UINT(0,255,0,255));    // FIXME make a themeable colour
 
 		sync_line = new ArdourCanvas::Line (group);
+		CANVAS_DEBUG_NAME (sync_line, string_compose ("sync mark for %1", get_item_name()));
 		sync_line->set_outline_color (RGBA_TO_UINT(0,255,0,255)); // FIXME make a themeable colour
 	}
 
@@ -930,32 +932,12 @@ RegionView::thaw_after_trim ()
 
 
 void
-RegionView::trim_contents (framepos_t frame_delta, bool left_direction, bool swap_direction)
+RegionView::move_contents (frameoffset_t distance)
 {
 	if (_region->locked()) {
 		return;
 	}
-
-	framepos_t new_bound;
-
-	RouteTimeAxisView& rtv = dynamic_cast<RouteTimeAxisView&> (trackview);
-	double const speed = rtv.track()->speed ();
-
-	if (left_direction) {
-		if (swap_direction) {
-			new_bound = (framepos_t) (_region->position() / speed) + frame_delta;
-		} else {
-			new_bound = (framepos_t) (_region->position() / speed) - frame_delta;
-		}
-	} else {
-		if (swap_direction) {
-			new_bound = (framepos_t) (_region->position() / speed) - frame_delta;
-		} else {
-			new_bound = (framepos_t) (_region->position() / speed) + frame_delta;
-		}
-	}
-
-	_region->trim_start ((framepos_t) (new_bound * speed));
+	_region->move_start (distance);
 	region_changed (PropertyChange (ARDOUR::Properties::start));
 }
 
diff --git a/gtk2_ardour/region_view.h b/gtk2_ardour/region_view.h
index 566304fa92..74d1f29581 100644
--- a/gtk2_ardour/region_view.h
+++ b/gtk2_ardour/region_view.h
@@ -113,7 +113,7 @@ class RegionView : public TimeAxisViewItem
 	virtual void trim_front_ending () {}
 
 	bool trim_end (framepos_t, bool);
-	void trim_contents (framepos_t, bool, bool);
+        void move_contents (ARDOUR::frameoffset_t);
 	virtual void thaw_after_trim ();
 
         void set_silent_frames (const ARDOUR::AudioIntervalResult&, double threshold);
diff --git a/gtk2_ardour/streamview.cc b/gtk2_ardour/streamview.cc
index 774e150f13..8239bca2f4 100644
--- a/gtk2_ardour/streamview.cc
+++ b/gtk2_ardour/streamview.cc
@@ -71,8 +71,10 @@ StreamView::StreamView (RouteTimeAxisView& tv)
 	canvas_rect->set (ArdourCanvas::Rect (0, 0, ArdourCanvas::COORD_MAX, tv.current_height ()));
 	canvas_rect->raise(1); // raise above tempo lines
 
-	canvas_rect->set_outline_what (0x2 | 0x8);
+	canvas_rect->set_outline_what (ArdourCanvas::Rectangle::What (ArdourCanvas::Rectangle::TOP | ArdourCanvas::Rectangle::BOTTOM));
 	canvas_rect->set_outline_color (RGBA_TO_UINT (0, 0, 0, 255));
+	canvas_rect->set_fill_color (RGBA_TO_UINT (1.0, 0, 0, 255));
+	canvas_rect->set_fill (true);
 
 	canvas_rect->Event.connect (sigc::bind (
 			sigc::mem_fun (_trackview.editor(), &PublicEditor::canvas_stream_view_event),
diff --git a/gtk2_ardour/tempo_lines.cc b/gtk2_ardour/tempo_lines.cc
index a6177d2b1d..d73fb54b81 100644
--- a/gtk2_ardour/tempo_lines.cc
+++ b/gtk2_ardour/tempo_lines.cc
@@ -47,17 +47,13 @@ TempoLines::tempo_map_changed()
 void
 TempoLines::show ()
 {
-	for (Lines::iterator i = _lines.begin(); i != _lines.end(); ++i) {
-		(*i)->show();
-	}
+	_group->show ();
 }
 
 void
 TempoLines::hide ()
 {
-	for (Lines::iterator i = _lines.begin(); i != _lines.end(); ++i) {
-		(*i)->hide();
-	}
+	_group->hide ();
 }
 
 void
@@ -111,6 +107,8 @@ TempoLines::draw (const ARDOUR::TempoMap::BBTPointList::const_iterator& begin,
 			line->reparent (_group);
 		} else {
 			line = new ArdourCanvas::Line (_group);
+			CANVAS_DEBUG_NAME (line, "tempo measure line");
+			line->set_ignore_events (true);
 		}
 
 		line->set_x0 (xpos);
diff --git a/gtk2_ardour/time_axis_view.cc b/gtk2_ardour/time_axis_view.cc
index cfa22ae805..280802ab68 100644
--- a/gtk2_ardour/time_axis_view.cc
+++ b/gtk2_ardour/time_axis_view.cc
@@ -32,6 +32,7 @@
 #include <gtkmm2ext/selector.h>
 
 #include "canvas/rectangle.h"
+#include "canvas/debug.h"
 
 #include "ardour_ui.h"
 #include "ardour_dialog.h"
@@ -940,13 +941,16 @@ TimeAxisView::get_selection_rect (uint32_t id)
 		rect = new SelectionRect;
 
 		rect->rect = new ArdourCanvas::Rectangle (selection_group);
+		CANVAS_DEBUG_NAME (rect->rect, "selection rect");
 		rect->rect->set_outline_what (0);
 		rect->rect->set_fill_color (ARDOUR_UI::config()->get_canvasvar_SelectionRect());
 
 		rect->start_trim = new ArdourCanvas::Rectangle (selection_group);
+		CANVAS_DEBUG_NAME (rect->rect, "selection rect start trim");
 		rect->start_trim->set_outline_what (0);
 
 		rect->end_trim = new ArdourCanvas::Rectangle (selection_group);
+		CANVAS_DEBUG_NAME (rect->rect, "selection rect end trim");
 		rect->end_trim->set_outline_what (0);
 
 		free_selection_rects.push_front (rect);
diff --git a/gtk2_ardour/time_axis_view_item.cc b/gtk2_ardour/time_axis_view_item.cc
index 57bda5fa26..4c2e31c22d 100644
--- a/gtk2_ardour/time_axis_view_item.cc
+++ b/gtk2_ardour/time_axis_view_item.cc
@@ -138,6 +138,7 @@ TimeAxisViewItem::TimeAxisViewItem (const TimeAxisViewItem& other)
 	ArdourCanvas::Group* parent = other.group->parent();
 
 	group = new ArdourCanvas::Group (parent);
+	CANVAS_DEBUG_NAME (group, string_compose ("TAVI group for %1", get_item_name()));
 
 	_selected = other._selected;
 
@@ -171,6 +172,7 @@ TimeAxisViewItem::init (const string& it_name, double fpp, Gdk::Color const & ba
 	}
 
 	vestigial_frame = new ArdourCanvas::Rectangle (group, ArdourCanvas::Rect (0.0, 1.0, 2.0, trackview.current_height()));
+	CANVAS_DEBUG_NAME (vestigial_frame, string_compose ("vestigial frame for %1", get_item_name()));
 	vestigial_frame->hide ();
 	vestigial_frame->set_outline_color (ARDOUR_UI::config()->get_canvasvar_VestigialFrame());
 	vestigial_frame->set_fill_color (ARDOUR_UI::config()->get_canvasvar_VestigialFrame());
@@ -180,6 +182,7 @@ TimeAxisViewItem::init (const string& it_name, double fpp, Gdk::Color const & ba
 						     ArdourCanvas::Rect (0.0, 1.0, 
 									 trackview.editor().sample_to_pixel(duration), 
 									 trackview.current_height()));
+		CANVAS_DEBUG_NAME (frame, string_compose ("frame for %1", get_item_name()));
 
 		if (_recregion) {
 			frame->set_outline_color (ARDOUR_UI::config()->get_canvasvar_RecordingRect());
@@ -199,11 +202,13 @@ TimeAxisViewItem::init (const string& it_name, double fpp, Gdk::Color const & ba
 								      ArdourCanvas::Rect (0.0, trackview.editor().sample_to_pixel(item_duration),
 											  trackview.current_height() - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE, 
 											  trackview.current_height()));
+			CANVAS_DEBUG_NAME (name_highlight, string_compose ("name highlight for %1", get_item_name()));
 		} else {
 			name_highlight = new ArdourCanvas::Rectangle (group, 
 								      ArdourCanvas::Rect (1.0, trackview.editor().sample_to_pixel(item_duration) - 1, 
 											  trackview.current_height() - TimeAxisViewItem::NAME_HIGHLIGHT_SIZE, 
 											  trackview.current_height()));
+			CANVAS_DEBUG_NAME (name_highlight, string_compose ("name highlight for %1", get_item_name()));
 		}
 
 		name_highlight->set_data ("timeaxisviewitem", this);
@@ -217,6 +222,7 @@ TimeAxisViewItem::init (const string& it_name, double fpp, Gdk::Color const & ba
 
 	if (visibility & ShowNameText) {
 		name_text = new ArdourCanvas::Text (group);
+		CANVAS_DEBUG_NAME (name_text, string_compose ("name text for %1", get_item_name()));
 		name_text->set_position (ArdourCanvas::Duple (NAME_X_OFFSET, trackview.current_height() - NAME_Y_OFFSET));
 		name_text->set_font_description (NAME_FONT);
 		
@@ -230,9 +236,16 @@ TimeAxisViewItem::init (const string& it_name, double fpp, Gdk::Color const & ba
 		double width = TimeAxisViewItem::GRAB_HANDLE_WIDTH;
 
 		frame_handle_start = new ArdourCanvas::Rectangle (group, ArdourCanvas::Rect (0.0, top, width, trackview.current_height()));
-		frame_handle_start->set_outline_what (ArdourCanvas::Rectangle::What (0));
+		CANVAS_DEBUG_NAME (frame_handle_start, "TAVI frame handle start");
+		frame_handle_start->set_outline (false);
+		frame_handle_start->set_fill (false);
+		frame_handle_start->Event.connect (sigc::bind (sigc::mem_fun (*this, &TimeAxisViewItem::frame_handle_crossing), frame_handle_start));
+
 		frame_handle_end = new ArdourCanvas::Rectangle (group, ArdourCanvas::Rect (0.0, top, width, trackview.current_height()));
-		frame_handle_end->set_outline_what (ArdourCanvas::Rectangle::What (0));
+		CANVAS_DEBUG_NAME (frame_handle_end, "TAVI frame handle end");
+		frame_handle_end->set_outline (false);
+		frame_handle_end->set_fill (false);
+		frame_handle_end->Event.connect (sigc::bind (sigc::mem_fun (*this, &TimeAxisViewItem::frame_handle_crossing), frame_handle_end));
 	} else {
 		frame_handle_start = frame_handle_end = 0;
 	}
@@ -819,12 +832,28 @@ TimeAxisViewItem::set_trim_handle_colors()
 			frame_handle_start->set_fill_color (ARDOUR_UI::config()->get_canvasvar_TrimHandleLocked());
 			frame_handle_end->set_fill_color (ARDOUR_UI::config()->get_canvasvar_TrimHandleLocked());
 		} else {
-			frame_handle_start->set_fill_color (RGBA_TO_UINT (1, 1, 1, 0)); //ARDOUR_UI::config()->get_canvasvar_TrimHandle();
-			frame_handle_end->set_fill_color (RGBA_TO_UINT (1, 1, 1, 0)); //ARDOUR_UI::config()->get_canvasvar_TrimHandle();
+			frame_handle_start->set_fill_color (ARDOUR_UI::config()->get_canvasvar_TrimHandle());
+			frame_handle_end->set_fill_color (ARDOUR_UI::config()->get_canvasvar_TrimHandle());
 		}
 	}
 }
 
+bool
+TimeAxisViewItem::frame_handle_crossing (GdkEvent* ev, ArdourCanvas::Rectangle* item)
+{
+	switch (ev->type) {
+	case GDK_LEAVE_NOTIFY:
+		item->set_fill (false);
+		break;
+	case GDK_ENTER_NOTIFY:
+		item->set_fill (true);
+		break;
+	default:
+		break;
+	}
+	return false;
+}
+
 /** @return the frames per pixel */
 double
 TimeAxisViewItem::get_samples_per_pixel () const
@@ -901,6 +930,7 @@ TimeAxisViewItem::reset_width_dependent_items (double pixel_width)
 				 * the right-hand end of frame_handle_start and the left-hand
 				 * end of frame_handle_end, so disable the handles
 				 */
+
 				frame_handle_start->hide();
 				frame_handle_end->hide();
 			} else {
diff --git a/gtk2_ardour/time_axis_view_item.h b/gtk2_ardour/time_axis_view_item.h
index f6f72b77bd..08cc421202 100644
--- a/gtk2_ardour/time_axis_view_item.h
+++ b/gtk2_ardour/time_axis_view_item.h
@@ -21,6 +21,7 @@
 #define __gtk_ardour_time_axis_view_item_h__
 
 #include <string>
+#include <gdk/gdk.h>
 #include <gdkmm/color.h>
 #include <pangomm/fontdescription.h>
 #include "pbd/signals.h"
@@ -244,6 +245,8 @@ class TimeAxisViewItem : public Selectable, public PBD::ScopedConnectionList
 	ArdourCanvas::Rectangle* frame_handle_start; ///< `frame' (fade) handle for the start of the item, or 0
 	ArdourCanvas::Rectangle* frame_handle_end; ///< `frame' (fade) handle for the end of the item, or 0
 
+        bool frame_handle_crossing (GdkEvent*, ArdourCanvas::Rectangle*);
+
 	double _height;
 	Visibility visibility;
 	bool _recregion;
diff --git a/gtk2_ardour/verbose_cursor.cc b/gtk2_ardour/verbose_cursor.cc
index 1f43f754e6..fec9e80ae1 100644
--- a/gtk2_ardour/verbose_cursor.cc
+++ b/gtk2_ardour/verbose_cursor.cc
@@ -22,6 +22,8 @@
 #include "pbd/stacktrace.h"
 #include "ardour/profile.h"
 
+#include "canvas/debug.h"
+
 #include "ardour_ui.h"
 #include "audio_clock.h"
 #include "editor.h"
@@ -42,10 +44,9 @@ VerboseCursor::VerboseCursor (Editor* editor)
 	, _yoffset (0)
 {
 	_canvas_item = new ArdourCanvas::Text (_editor->_track_canvas->root());
+	CANVAS_DEBUG_NAME (_canvas_item, "verbose canvas cursor");
 	_canvas_item->set_ignore_events (true);
 	_canvas_item->set_font_description (get_font_for_style (N_("VerboseCanvasCursor")));
-	// CAIROCANVAS
-	// _canvas_item->property_anchor() = Gtk::ANCHOR_NW;
 }
 
 ArdourCanvas::Item *
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index 3ee829ed12..593832343f 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -220,7 +220,7 @@ class Region
 	bool at_natural_position () const;
 	void move_to_natural_position ();
 
-	void trim_start (framepos_t new_position);
+	void move_start (frameoffset_t distance);
 	void trim_front (framepos_t new_position);
 	void trim_end (framepos_t new_position);
 	void trim_to (framepos_t position, framecnt_t length);
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 706dda4a0a..847a72b23f 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -698,33 +698,32 @@ Region::set_start (framepos_t pos)
 }
 
 void
-Region::trim_start (framepos_t new_position)
+Region::move_start (frameoffset_t distance)
 {
 	if (locked() || position_locked() || video_locked()) {
 		return;
 	}
 
 	framepos_t new_start;
-	frameoffset_t const start_shift = new_position - _position;
 
-	if (start_shift > 0) {
+	if (distance > 0) {
 
-		if (_start > max_framepos - start_shift) {
-			new_start = max_framepos;
+		if (_start > max_framepos - distance) {
+			new_start = max_framepos; // makes no sense
 		} else {
-			new_start = _start + start_shift;
+			new_start = _start + distance;
 		}
 
 		if (!verify_start (new_start)) {
 			return;
 		}
 
-	} else if (start_shift < 0) {
+	} else if (distance < 0) {
 
-		if (_start < -start_shift) {
+		if (_start < -distance) {
 			new_start = 0;
 		} else {
-			new_start = _start + start_shift;
+			new_start = _start + distance;
 		}
 
 	} else {
@@ -736,6 +735,7 @@ Region::trim_start (framepos_t new_position)
 	}
 
 	set_start_internal (new_start);
+
 	_whole_file = false;
 	first_edit ();
 
diff --git a/libs/canvas/canvas.cc b/libs/canvas/canvas.cc
index 9707f2304d..48bfbaaf4d 100644
--- a/libs/canvas/canvas.cc
+++ b/libs/canvas/canvas.cc
@@ -61,9 +61,10 @@ Canvas::render (Rect const & area, Cairo::RefPtr<Cairo::Context> const & context
 {
 #ifdef CANVAS_DEBUG
 	if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-		cerr << "CANVAS @ " << this << endl;
-		dump (cerr);
-		cerr << "-------------------------\n";
+		cerr << "RENDER: " << area << endl;
+		//cerr << "CANVAS @ " << this << endl;
+		//dump (cerr);
+		//cerr << "-------------------------\n";
 	}
 #endif
 
@@ -78,9 +79,9 @@ Canvas::render (Rect const & area, Cairo::RefPtr<Cairo::Context> const & context
 		context->set_source_rgba (random()%255 / 255.0,
 					  random()%255 / 255.0,
 					  random()%255 / 255.0,
-					  255);
+					  0.3);
 		context->rectangle (area.x0, area.y0, area.width(), area.height());
-		context->stroke ();
+		context->fill ();
 	}
 #endif
 
@@ -119,7 +120,7 @@ Canvas::render (Rect const & area, Cairo::RefPtr<Cairo::Context> const & context
 		context->set_source_rgba (random()%255 / 255.0,
 					  random()%255 / 255.0,
 					  random()%255 / 255.0,
-					  255);
+					  0.4);
 		context->rectangle (area.x0, area.y0, area.width(), area.height());
 		context->fill ();
 	}
@@ -327,6 +328,11 @@ GtkCanvas::enter_leave_items ()
 {
 	int x;
 	int y;
+
+	/* this version of ::enter_leave_items() is called after an item is
+	 * added or removed, so we have no coordinates to work from as is the
+	 * case with a motion event. Find out where the mouse is and use that.
+	 */
 	     
 	Glib::RefPtr<const Gdk::Window> pointer_window = Gdk::Display::get_default()->get_window_at_pointer (x, y);
 
@@ -340,31 +346,60 @@ GtkCanvas::enter_leave_items ()
 void
 GtkCanvas::enter_leave_items (Duple const & point)
 {
-	/* find the items at the new mouse position */
+	/* find the items at the given position */
+
 	vector<Item const *> items;
 	_root.add_items_at_point (point, items);
 
-	Item const * new_item = items.empty() ? 0 : items.back ();
-
-	if (_current_item && _current_item != new_item) {
-		/* leave event */
-		GdkEventCrossing leave_event;
-		leave_event.type = GDK_LEAVE_NOTIFY;
-		leave_event.x = point.x;
-		leave_event.y = point.y;
-		_current_item->Event (reinterpret_cast<GdkEvent*> (&leave_event));
+	if (items.empty()) {
+		if (_current_item) {
+			/* leave event */
+			GdkEventCrossing leave_event;
+			leave_event.type = GDK_LEAVE_NOTIFY;
+			leave_event.x = point.x;
+			leave_event.y = point.y;
+			cerr << "Leaving (without entering)" << _current_item->name << endl;
+			_current_item->Event (reinterpret_cast<GdkEvent*> (&leave_event));
+			_current_item = 0;
+		}
+		return;
 	}
 
-	if (new_item && _current_item != new_item) {
-		/* enter event */
-		GdkEventCrossing enter_event;
-		enter_event.type = GDK_ENTER_NOTIFY;
-		enter_event.x = point.x;
-		enter_event.y = point.y;
-		new_item->Event (reinterpret_cast<GdkEvent*> (&enter_event));
-	}
+	/* items is sorted from bottom to top, so reverse through it from top
+	 * to bottom to find the first event-sensitive item and notify that
+	 * we have entered it
+	 */
 
-	_current_item = new_item;
+	for (vector<Item const*>::const_reverse_iterator i = items.rbegin(); i != items.rend(); ++i) {
+
+		Item const *  new_item = *i;
+
+		if (new_item->ignore_events()) {
+			continue;
+		}
+		if (_current_item && _current_item != new_item) {
+			/* leave event */
+			GdkEventCrossing leave_event;
+			leave_event.type = GDK_LEAVE_NOTIFY;
+			leave_event.x = point.x;
+			leave_event.y = point.y;
+			cerr << "Leaving " << _current_item->name << endl;
+			_current_item->Event (reinterpret_cast<GdkEvent*> (&leave_event));
+		}
+
+		if (new_item && _current_item != new_item) {
+			/* enter event */
+			GdkEventCrossing enter_event;
+			enter_event.type = GDK_ENTER_NOTIFY;
+			enter_event.x = point.x;
+			enter_event.y = point.y;
+			cerr << "Entering (" << new_item->name << ") " << new_item->whatami() << endl;
+			new_item->Event (reinterpret_cast<GdkEvent*> (&enter_event));
+		}
+	
+		_current_item = new_item;
+		break;
+	}
 }
 
 /** Deliver an event to the appropriate item; either the grabbed item, or
diff --git a/libs/canvas/canvas/wave_view.h b/libs/canvas/canvas/wave_view.h
index f88ca41ba4..b75b8c5312 100644
--- a/libs/canvas/canvas/wave_view.h
+++ b/libs/canvas/canvas/wave_view.h
@@ -105,17 +105,31 @@ private:
 
 #endif
 
+    /** A cached, pre-rendered image of some section of a waveform.
+	
+	It spans a range given relative to the start of the source
+	of the waveform data, so a range from N..M corresponds
+	to the sample range N..M within the source.
+	
+	Invalidated by a changes to:
+
+               samples_per_pixel
+               colors
+	       height
+
+    */
+
 	class CacheEntry
 	{
-	public:
-		CacheEntry (WaveView const *, int, int);
+	  public:
+  	        CacheEntry (WaveView const *, double, double, int);
 		~CacheEntry ();
 
-		int start () const {
+	        double start () const {
 			return _start;
 		}
 
-		int end () const {
+  	        double end () const {
 			return _end;
 		}
 
@@ -130,9 +144,11 @@ private:
 		Coord position (Coord) const;
 		
 		WaveView const * _wave_view;
-		int _start;
-		int _end;
-		int _n_peaks;
+	        
+	        double _start;
+	        double _end;
+	        int _n_peaks; 
+
 	        boost::shared_array<ARDOUR::PeakData> _peaks;
 	        Cairo::RefPtr<Cairo::ImageSurface> _image;
 	};
@@ -163,7 +179,7 @@ private:
 	 *  value as the crossfade editor needs to alter it.
 	 */
 	ARDOUR::frameoffset_t _region_start;
-	
+
 	mutable std::list<CacheEntry*> _cache;
        
         PBD::ScopedConnection invalidation_connection;
diff --git a/libs/canvas/group.cc b/libs/canvas/group.cc
index fe783ad8b5..1272d0e438 100644
--- a/libs/canvas/group.cc
+++ b/libs/canvas/group.cc
@@ -88,7 +88,7 @@ Group::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 		if (!(*i)->visible ()) {
 #ifdef CANVAS_DEBUG
 			if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-				cerr << _canvas->render_indent() << "Item " << (*i)->whatami() << " [" << (*i)->name << "] invisible - skipped\n";
+				// cerr << _canvas->render_indent() << "Item " << (*i)->whatami() << " [" << (*i)->name << "] invisible - skipped\n";
 			}
 #endif
 			continue;
@@ -99,7 +99,7 @@ Group::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 		if (!item_bbox) {
 #ifdef CANVAS_DEBUG
 			if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-				cerr << _canvas->render_indent() << "Item " << (*i)->whatami() << " [" << (*i)->name << "] empty - skipped\n";
+				// cerr << _canvas->render_indent() << "Item " << (*i)->whatami() << " [" << (*i)->name << "] empty - skipped\n";
 			}
 #endif
 			continue;
@@ -127,8 +127,8 @@ Group::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 		} else {
 #ifdef CANVAS_DEBUG
 			if (DEBUG_ENABLED(PBD::DEBUG::CanvasRender)) {
-				cerr << string_compose ("%1skip render of %2 %3, no intersection\n", _canvas->render_indent(), (*i)->whatami(),
-							(*i)->name);
+				//cerr << string_compose ("%1skip render of %2 %3, no intersection\n", _canvas->render_indent(), (*i)->whatami(),
+				// (*i)->name);
 			}
 #endif
 		}
diff --git a/libs/canvas/outline.cc b/libs/canvas/outline.cc
index 15ea4776b6..3e57887070 100644
--- a/libs/canvas/outline.cc
+++ b/libs/canvas/outline.cc
@@ -41,35 +41,33 @@ Outline::Outline (Group* parent)
 void
 Outline::set_outline_color (Color color)
 {
-	begin_visual_change ();
-	
-	_outline_color = color;
-
-	end_visual_change ();
+	if (color != _outline_color) {
+		begin_visual_change ();
+		_outline_color = color;
+		end_visual_change ();
+	}
 }
 
 void
 Outline::set_outline_width (Distance width)
 {
-	begin_change ();
-	
-	_outline_width = width;
-
-	_bounding_box_dirty = true;
-	end_change ();
-
-	DEBUG_TRACE (PBD::DEBUG::CanvasItemsDirtied, "canvas item dirty: outline width change\n");	
+	if (width != _outline_width) {
+		begin_change ();
+		_outline_width = width;
+		_bounding_box_dirty = true;
+		end_change ();
+	}
 }
 
 void
 Outline::set_outline (bool outline)
 {
-	begin_change ();
-
-	_outline = outline;
-
-	_bounding_box_dirty = true;
-	end_change ();
+	if (outline != _outline) {
+		begin_change ();
+		_outline = outline;
+		_bounding_box_dirty = true;
+		end_change ();
+	}
 }
 
 void
diff --git a/libs/canvas/wave_view.cc b/libs/canvas/wave_view.cc
index c6ba816288..f39dca7594 100644
--- a/libs/canvas/wave_view.cc
+++ b/libs/canvas/wave_view.cc
@@ -25,6 +25,7 @@
 
 #include "pbd/compose.h"
 #include "pbd/signals.h"
+#include "pbd/stacktrace.h"
 
 #include "ardour/types.h"
 #include "ardour/dB.h"
@@ -65,7 +66,7 @@ WaveView::WaveView (Group* parent, boost::shared_ptr<ARDOUR::AudioRegion> region
 	, _logscaled_independent (false)
 	, _gradient_depth_independent (false)
 	, _amplitude_above_axis (1.0)
-	, _region_start (0)
+	, _region_start (region->start())
 {
 	VisualPropertiesChanged.connect_same_thread (invalidation_connection, boost::bind (&WaveView::handle_visual_property_change, this));
 }
@@ -98,28 +99,47 @@ WaveView::handle_visual_property_change ()
 void
 WaveView::set_fill_color (Color c)
 {
-	invalidate_image_cache ();
-	Fill::set_fill_color (c);
+	if (c != _fill_color) {
+		invalidate_image_cache ();
+		Fill::set_fill_color (c);
+	}
 }
 
 void
 WaveView::set_outline_color (Color c)
 {
-	invalidate_image_cache ();
-	Outline::set_outline_color (c);
+	if (c != _outline_color) {
+		invalidate_image_cache ();
+		Outline::set_outline_color (c);
+	}
 }
 
 void
 WaveView::set_samples_per_pixel (double samples_per_pixel)
 {
-	begin_change ();
+	if (samples_per_pixel != _samples_per_pixel) {
+		begin_change ();
 	
-	_samples_per_pixel = samples_per_pixel;
+		_samples_per_pixel = samples_per_pixel;
+		
+		_bounding_box_dirty = true;
+		
+		end_change ();
+		
+		invalidate_whole_cache ();
+	}
+}
 
-	_bounding_box_dirty = true;
-	end_change ();
+static inline double
+to_src_sample_offset (frameoffset_t src_sample_start, double pixel_offset, double spp)
+{
+	return src_sample_start + (pixel_offset * spp);
+}
 
-	invalidate_whole_cache ();
+static inline double
+to_pixel_offset (frameoffset_t src_sample_start, double sample_offset, double spp)
+{
+	return (sample_offset - src_sample_start) / spp;
 }
 
 void
@@ -131,53 +151,91 @@ WaveView::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) cons
 		return;
 	}
 
-	/* p, start and end are offsets from the start of the source.
-	   area is relative to the position of the region.
+	/* These are all pixel (integer) coordinates from the left hand edge of
+	 * the waveview.
 	 */
 	
-	int const start = rint (area.x0 + _region_start / _samples_per_pixel);
-	int const end   = rint (area.x1 + _region_start / _samples_per_pixel);
+	double       start = area.x0;
+	double const end   = area.x1;
+	double const rend  = _region->length() / _samples_per_pixel;
 
-	int p = start;
 	list<CacheEntry*>::iterator cache = _cache.begin ();
 
-	while (p < end) {
+	while ((end - start) > 1.0) {
+
+		frameoffset_t start_sample_offset = to_src_sample_offset (_region_start, start, _samples_per_pixel);
 
-		/* Step through cache entries that end at or before our current position, p */
-		while (cache != _cache.end() && (*cache)->end() <= p) {
+		/* Step through cache entries that end at or before our current position */
+
+		while (cache != _cache.end() && (*cache)->end() <= start_sample_offset) {
 			++cache;
 		}
 
 		/* Now either:
 		   1. we have run out of cache entries
-		   2. the one we are looking at finishes after p but also starts after p.
-		   3. the one we are looking at finishes after p and starts before p.
+		   2. the one we are looking at finishes after start(_sample_offset) but also starts after start(_sample_offset).
+		   3. the one we are looking at finishes after start(_sample_offset) and starts before start(_sample_offset).
 
 		   Set up a pointer to the cache entry that we will use on this iteration.
 		*/
 
-		CacheEntry* render = 0;
+		CacheEntry* image = 0;
 
 		if (cache == _cache.end ()) {
 
 			/* Case 1: we have run out of cache entries, so make a new one for
 			   the whole required area and put it in the list.
+			   
+			   We would like to avoid lots of little images in the
+			   cache, so when we create a new one, make it as wide
+			   as possible, within a sensible limit (here, the
+			   visible width of the canvas we're on). 
+
+			   However, we don't want to try to make it larger than 
+			   the region actually is, so clamp with that too.
 			*/
-			
-			CacheEntry* c = new CacheEntry (this, p, end);
+
+			double const endpoint = min (rend, max (end, start + _canvas->visible_area().width()));
+			CacheEntry* c = new CacheEntry (this, 
+							start_sample_offset,
+							to_src_sample_offset (_region_start, endpoint, _samples_per_pixel),
+							endpoint - start);
 			_cache.push_back (c);
-			render = c;
+			image = c;
 
-		} else if ((*cache)->start() > p) {
+		} else if ((*cache)->start() > start_sample_offset) {
 
-			/* Case 2: we have a cache entry, but it starts after p, so we
-			   need another one for the missing bit.
-			*/
+			/* Case 2: we have a cache entry, but it starts after
+			 * start(_sample_offset), so we need another one for
+			 * the missing bit.
+			 *  
+			 * Create a new cached image that extends as far as the
+			 * next cached image's start, or the end of the region,
+			 * or the end of the render area, whichever comes first.
+			 */
+
+			double    end_pixel = min (rend, end);
+			double end_sample_offset = to_src_sample_offset (_region_start, end_pixel, _samples_per_pixel);
+			int npeaks;
+
+			if (end_sample_offset < (*cache)->start()) {
+				npeaks = end_pixel - start;
+				assert (npeaks > 0);
+			} else {
+				end_sample_offset = (*cache)->start();
+				end_pixel = to_pixel_offset (_region_start, end_sample_offset, _samples_per_pixel);
+				npeaks = end_pixel - npeaks;
+				assert (npeaks > 0);
+			}
+		
+			CacheEntry* c = new CacheEntry (this,
+							start_sample_offset,
+							end_sample_offset,
+							npeaks);
 
-			CacheEntry* c = new CacheEntry (this, p, min (end, (*cache)->start()));
 			cache = _cache.insert (cache, c);
 			++cache;
-			render = c;
+			image = c;
 
 		} else {
 
@@ -185,29 +243,19 @@ WaveView::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) cons
 			   we have left, so render it.
 			*/
 
-			render = *cache;
+			image = *cache;
 			++cache;
 
 		}
 
-		int const this_end = min (end, render->end ());
-		
-		Coord const left  =        p - _region_start / _samples_per_pixel;
-		Coord const right = this_end - _region_start / _samples_per_pixel;
-		
-		context->save ();
-		
-		context->rectangle (left, area.y0, right, area.height());
-		context->clip ();
-		
-		context->translate (left, 0);
+		double this_end = min (end, to_pixel_offset (_region_start, image->end (), _samples_per_pixel));
+		double const image_origin = to_pixel_offset (_region_start, image->start(), _samples_per_pixel);
 
-		context->set_source (render->image(), render->start() - p, 0);
-		context->paint ();
+		context->rectangle (start, area.y0, this_end - start, area.height());
+		context->set_source (image->image(), image_origin, 0);
+		context->fill ();
 		
-		context->restore ();
-
-		p = min (end, render->end ());
+		start = this_end;
 	}
 }
 
@@ -215,7 +263,7 @@ void
 WaveView::compute_bounding_box () const
 {
 	if (_region) {
-		_bounding_box = Rect (0, 0, _region->length() / _samples_per_pixel, _height);
+		_bounding_box = Rect (0.0, 0.0, _region->length() / _samples_per_pixel, _height);
 	} else {
 		_bounding_box = boost::optional<Rect> ();
 	}
@@ -226,33 +274,38 @@ WaveView::compute_bounding_box () const
 void
 WaveView::set_height (Distance height)
 {
-	begin_change ();
-
-	_height = height;
-
-	_bounding_box_dirty = true;
-	end_change ();
-
-	invalidate_image_cache ();
+	if (height != _height) {
+		begin_change ();
+		
+		_height = height;
+		
+		_bounding_box_dirty = true;
+		end_change ();
+		
+		invalidate_image_cache ();
+	}
 }
 
 void
 WaveView::set_channel (int channel)
 {
-	begin_change ();
-	
-	_channel = channel;
-
-	_bounding_box_dirty = true;
-	end_change ();
-
-	invalidate_whole_cache ();
+	if (channel != _channel) {
+		begin_change ();
+		
+		_channel = channel;
+		
+		_bounding_box_dirty = true;
+		end_change ();
+		
+		invalidate_whole_cache ();
+	}
 }
 
 void
 WaveView::invalidate_whole_cache ()
 {
 	begin_visual_change ();
+
 	for (list<CacheEntry*>::iterator i = _cache.begin(); i != _cache.end(); ++i) {
 		delete *i;
 	}
@@ -266,7 +319,7 @@ void
 WaveView::invalidate_image_cache ()
 {
 	begin_visual_change ();
-
+	
 	for (list<CacheEntry*>::iterator i = _cache.begin(); i != _cache.end(); ++i) {
 		(*i)->clear_image ();
 	}
@@ -275,12 +328,6 @@ WaveView::invalidate_image_cache ()
 }
 
 void
-WaveView::region_resized ()
-{
-	_bounding_box_dirty = true;
-}
-
-void
 WaveView::set_logscaled (bool yn)
 {
 	if (_logscaled != yn) {
@@ -360,31 +407,41 @@ WaveView::set_global_logscaled (bool yn)
 }
 
 void
-WaveView::set_region_start (frameoffset_t start)
+WaveView::region_resized ()
 {
-	_region_start = start;
+	if (!_region) {
+		return;
+	}
+
+	/* special: do not use _region->length() here to compute
+	   bounding box because it will already have changed.
+	   
+	   if we have a bounding box, use it.
+	*/
+
+	_pre_change_bounding_box = _bounding_box;
+
+	_region_start = _region->start();
+	invalidate_whole_cache ();
+
 	_bounding_box_dirty = true;
+	compute_bounding_box ();
+
+	end_change ();
 }
 
-/** Construct a new CacheEntry with peak data between two offsets
- *  in the source.
- */
-WaveView::CacheEntry::CacheEntry (WaveView const * wave_view, int start, int end)
+WaveView::CacheEntry::CacheEntry (WaveView const * wave_view, double start, double end, int npeaks)
 	: _wave_view (wave_view)
 	, _start (start)
 	, _end (end)
+	, _n_peaks (npeaks)
 {
-	_n_peaks = _end - _start;
 	_peaks.reset (new PeakData[_n_peaks]);
 
-	_wave_view->_region->read_peaks (
-		_peaks.get(),
-		_n_peaks,
-		_start * _wave_view->_samples_per_pixel,
-		(_end - _start) * _wave_view->_samples_per_pixel,
-		_wave_view->_channel,
-		_wave_view->_samples_per_pixel
-		);
+	_wave_view->_region->read_peaks (_peaks.get(), _n_peaks, 
+					 (framecnt_t) floor (_start), 
+					 (framecnt_t) ceil (_end), 
+					 _wave_view->_channel, _wave_view->_samples_per_pixel);
 }
 
 WaveView::CacheEntry::~CacheEntry ()