An actual tempo line cache (not quite perfect when scrolling left, but miles ahead of the previous one didn't really help at all).

Tempo line updating done immediately/directly rather than in an idle handler.
Looking for feedback how this works for other people, performance wise...
Feel-wise, the obvious lag between scrolling and tempo lines being drawn is now gone.


git-svn-id: svn://localhost/ardour2/branches/3.0@3799 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 115 insertions, 30 deletions

diff --git a/gtk2_ardour/tempo_lines.cc b/gtk2_ardour/tempo_lines.cc
index c234cb4c51..ed54708cc6 100644
--- a/gtk2_ardour/tempo_lines.cc
+++ b/gtk2_ardour/tempo_lines.cc
@@ -22,35 +22,52 @@
 #include "tempo_lines.h"
 #include "ardour_ui.h"
 
-ArdourCanvas::SimpleLine *
-TempoLines::get_line ()
+using namespace std;
+
+#define MAX_CACHED_LINES 512
+	
+TempoLines::TempoLines(ArdourCanvas::Canvas& canvas, ArdourCanvas::Group* group)
+	: _canvas(canvas)
+	, _group(group)
+	, _clean_left(DBL_MAX)
+	, _clean_right(0.0)
 {
-	ArdourCanvas::SimpleLine *line;
+}
 
-	if (_free_lines.empty()) {
-		line = new ArdourCanvas::SimpleLine (*_group);
-		_used_lines.push_back (line);
-	} else {
-		line = _free_lines.front();
-		_free_lines.erase (_free_lines.begin());
-		_used_lines.push_back (line);
+void
+TempoLines::tempo_map_changed()
+{
+	_clean_left = DBL_MAX;
+	_clean_right = 0.0;
+
+	// TODO: Dirty/slow, but 'needed' for zoom :(
+	for (Lines::iterator i = _lines.begin(); i != _lines.end(); ) {
+		Lines::iterator next = i;
+		++next;
+      	i->second->property_x1() = DBL_MAX;
+      	i->second->property_x2() = DBL_MAX;
+		_lines.erase(i);
+		_lines.insert(make_pair(DBL_MAX, i->second));
+		i = next;
 	}
-
-	return line;
 }
 
+void
+TempoLines::show ()
+{
+	for (Lines::iterator i = _lines.begin(); i != _lines.end(); ++i) {
+      	i->second->show();
+	}
+}
 
 void
 TempoLines::hide ()
 {
-	for (Lines::iterator i = _used_lines.begin(); i != _used_lines.end(); ++i) {
-      	(*i)->hide();
-		_free_lines.push_back (*i);
+	for (Lines::iterator i = _lines.begin(); i != _lines.end(); ++i) {
+      	i->second->hide();
 	}
-	_used_lines.clear ();
 }
 
-
 void
 TempoLines::draw (ARDOUR::TempoMap::BBTPointList& points, double frames_per_unit)
 {
@@ -63,6 +80,8 @@ TempoLines::draw (ARDOUR::TempoMap::BBTPointList& points, double frames_per_unit
 	uint32_t beats = 0;
 	uint32_t bars = 0;
 	uint32_t color;
+	
+	const size_t needed = points.size();
 
 	_canvas.get_scroll_region (x1, y1, x2, who_cares);
 	_canvas.root()->get_bounds(who_cares, who_cares, who_cares, y2);
@@ -74,14 +93,38 @@ TempoLines::draw (ARDOUR::TempoMap::BBTPointList& points, double frames_per_unit
 	bars = (*i).bar - (*points.begin()).bar;
 	beats = points.size() - bars;
 
-	beat_density =  (beats * 10.0f) / _canvas.get_width ();
+	beat_density = (beats * 10.0f) / _canvas.get_width ();
 
 	if (beat_density > 4.0f) {
-		/* if the lines are too close together, they become useless
-		 */
+		/* if the lines are too close together, they become useless */
 		return;
 	}
 
+	xpos = rint(((nframes64_t)(*i).frame) / (double)frames_per_unit);
+	const double needed_right = xpos;
+
+	i = points.begin();
+	
+	xpos = rint(((nframes64_t)(*i).frame) / (double)frames_per_unit);
+	const double needed_left = xpos;
+
+	Lines::iterator left = _lines.lower_bound(xpos); // first line >= xpos
+
+	bool exhausted = (left == _lines.end());
+	Lines::iterator li = left;
+	
+	// Tempo map hasn't changed and we're entirely within a clean
+	// range, don't need to do anything.  Yay.
+	if (needed_left >= _clean_left && needed_right <= _clean_right) {
+		//cout << "LINE CACHE PERFECT HIT!" << endl;
+		return;
+	}
+
+	//cout << "LINE CACHE MISS :/" << endl;
+
+	bool inserted_last_time = false;
+	bool invalidated = false;
+	
 	for (i = points.begin(); i != points.end(); ++i) {
 
 		switch ((*i).type) {
@@ -96,21 +139,63 @@ TempoLines::draw (ARDOUR::TempoMap::BBTPointList& points, double frames_per_unit
 				color = ARDOUR_UI::config()->canvasvar_MeasureLineBeat.get();
 
 				if (beat_density > 2.0) {
-					/* only draw beat lines if the gaps between beats are large.
-					*/
+					/* only draw beat lines if the gaps between beats are large. */
 					break;
 				}
 			}
-
+			
 			xpos = rint(((nframes64_t)(*i).frame) / (double)frames_per_unit);
-			line = get_line ();
-			line->property_x1() = xpos;
-			line->property_x2() = xpos;
-			line->property_y2() = y2;
-			line->property_color_rgba() = color;
-			//line->raise_to_top();
-			line->show();	
+
+			if (inserted_last_time) {
+				li = _lines.lower_bound(xpos); // first line >= xpos
+			}
+			
+			if (!exhausted) {
+				line = li->second;
+				exhausted = ((++li) == _lines.end());
+				inserted_last_time = false;
+			} else if (_lines.size() < needed || _lines.size() < MAX_CACHED_LINES) {
+				line = new ArdourCanvas::SimpleLine (*_group);
+				line->property_x1() = xpos;
+				line->property_x2() = xpos;
+				line->property_y2() = y2;
+				line->property_color_rgba() = color;
+				_lines.insert(make_pair(xpos, line));
+				inserted_last_time = true;
+			} else {
+				assert(li != _lines.begin());
+				line = _lines.begin()->second; // steal leftmost line
+				_lines.erase(_lines.begin());
+				_lines.insert(make_pair(xpos, line));
+				inserted_last_time = true;
+				invalidated = true;
+			}
+
+			/* At this point, line's key is correct, but actual pos may not be */
+			if (line->property_x1() != xpos) {
+				// Turn this on to see the case where this isn't quite ideal yet
+				// (scrolling left, lots of lines are moved left when there is
+				// likely to be a huge chunk with equivalent coords)
+				//cout << "MOVE " << line->property_x1() << " -> " << xpos << endl;
+				double x1 = line->property_x1();
+				bool was_clean = x1 >= _clean_left && x1 <= _clean_right;
+				invalidated = invalidated || was_clean;
+				line->property_x1() = xpos;
+				line->property_x2() = xpos;
+				line->property_y2() = y2;
+				line->property_color_rgba() = color;
+			}
+
 			break;
 		}
 	}
+	
+	if (invalidated) { // We messed things up, visible range is all we know is valid
+		_clean_left  = needed_left;
+		_clean_right = needed_right;
+	} else { // Extend range to what we've 'fixed'
+		_clean_left  = min(_clean_left, needed_left);
+		_clean_right = max(_clean_right, needed_right);
+	}
 }
+