From e3db2d3ca52620970c4c493d629b546da29aee47 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Tue, 16 Apr 2013 09:25:53 -0400
Subject: [PATCH] partially fix scaling issues with pathological MIDI regions
 (e.g. 15k notes per region), particularly during loading. more to be done,
 perhaps, for editing purposes where we redisplay the entire model after a
 change

---
 gtk2_ardour/midi_region_view.cc | 39 +++++++++++++++++----------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/gtk2_ardour/midi_region_view.cc b/gtk2_ardour/midi_region_view.cc
index db53215137..3b8e688ad3 100644
--- a/gtk2_ardour/midi_region_view.cc
+++ b/gtk2_ardour/midi_region_view.cc
@@ -1118,6 +1118,8 @@ MidiRegionView::redisplay_model()
 	MidiModel::Notes& notes (_model->notes());
 	_optimization_iterator = _events.begin();
 
+	bool empty_when_starting = !_events.empty();
+
 	for (MidiModel::Notes::iterator n = notes.begin(); n != notes.end(); ++n) {
 
 		boost::shared_ptr<NoteType> note (*n);
@@ -1126,7 +1128,7 @@ MidiRegionView::redisplay_model()
 
 		if (note_in_region_range (note, visible)) {
 
-			if ((cne = find_canvas_note (note)) != 0) {
+			if (empty_when_starting && (cne = find_canvas_note (note)) != 0) {
 
 				cne->validate ();
 
@@ -1152,7 +1154,7 @@ MidiRegionView::redisplay_model()
 
 		} else {
 
-			if ((cne = find_canvas_note (note)) != 0) {
+			if (empty_when_starting && (cne = find_canvas_note (note)) != 0) {
 				cne->validate ();
 				cne->hide ();
 			}
@@ -1162,21 +1164,23 @@ MidiRegionView::redisplay_model()
 
 	/* remove note items that are no longer valid */
 
-	for (Events::iterator i = _events.begin(); i != _events.end(); ) {
-		if (!(*i)->valid ()) {
-
-			for (vector<GhostRegion*>::iterator j = ghosts.begin(); j != ghosts.end(); ++j) {
-				MidiGhostRegion* gr = dynamic_cast<MidiGhostRegion*> (*j);
-				if (gr) {
-					gr->remove_note (*i);
+	if (empty_when_starting) {
+		for (Events::iterator i = _events.begin(); i != _events.end(); ) {
+			if (!(*i)->valid ()) {
+				
+				for (vector<GhostRegion*>::iterator j = ghosts.begin(); j != ghosts.end(); ++j) {
+					MidiGhostRegion* gr = dynamic_cast<MidiGhostRegion*> (*j);
+					if (gr) {
+						gr->remove_note (*i);
+					}
 				}
+				
+				delete *i;
+				i = _events.erase (i);
+				
+			} else {
+				++i;
 			}
-			
-			delete *i;
-			i = _events.erase (i);
-			
-		} else {
-			++i;
 		}
 	}
 
@@ -1360,16 +1364,13 @@ MidiRegionView::reset_width_dependent_items (double pixel_width)
 		redisplay_model();
 	}
 
-// CAIROCANVAS
-#if 0
 	for (PatchChanges::iterator x = _patch_changes.begin(); x != _patch_changes.end(); ++x) {
-		if ((*x)->width() >= _pixel_width) {
+		if ((*x)->canvas_item()->width() >= _pixel_width) {
 			(*x)->hide();
 		} else {
 			(*x)->show();
 		}
 	}
-#endif
 
 	move_step_edit_cursor (_step_edit_cursor_position);
 	set_step_edit_cursor_width (_step_edit_cursor_width);