Initial stab at tempo ramps.

Replaces the list of points in TempoMap with TempoSection functions, which
compute tempo-at or tick-at time relative to tempo section start.
TempoMap consults them additively to determine things like bbt_time(),
frame_time() get_grid() etc.
This has a marked effect on scrolling speed along with the code simplification
in the places it has been attempted.

Several things are broken here.
Currently every ramp except the last one is an exponential ramp. this may
be simple to fix :).
Mouse-over midi grid doesn't match mouse click grid. should also be simple.

Many things seem to work, but their accuracy should be in question until
each area has been addressed.

1 files changed, 91 insertions, 158 deletions

diff --git a/gtk2_ardour/editor_rulers.cc b/gtk2_ardour/editor_rulers.cc
index bb45e97bb3..ca450594e6 100644
--- a/gtk2_ardour/editor_rulers.cc
+++ b/gtk2_ardour/editor_rulers.cc
@@ -710,15 +710,13 @@ Editor::update_fixed_rulers ()
 }
 
 void
-Editor::update_tempo_based_rulers (ARDOUR::TempoMap::BBTPointList::const_iterator& begin,
-				    ARDOUR::TempoMap::BBTPointList::const_iterator& end)
+Editor::update_tempo_based_rulers (std::vector<TempoMap::BBTPoint>& grid)
 {
 	if (_session == 0) {
 		return;
 	}
 
-	compute_bbt_ruler_scale (leftmost_frame, leftmost_frame+current_page_samples(),
-				 begin, end);
+	compute_bbt_ruler_scale (grid, leftmost_frame, leftmost_frame+current_page_samples());
 
 	_bbt_metric->units_per_pixel = samples_per_pixel;
 
@@ -1011,19 +1009,19 @@ Editor::metric_get_timecode (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdou
 }
 
 void
-Editor::compute_bbt_ruler_scale (framepos_t lower, framepos_t upper,
-				 ARDOUR::TempoMap::BBTPointList::const_iterator begin,
-				 ARDOUR::TempoMap::BBTPointList::const_iterator end)
+Editor::compute_bbt_ruler_scale (std::vector<ARDOUR::TempoMap::BBTPoint>& grid, framepos_t lower, framepos_t upper)
 {
 	if (_session == 0) {
 		return;
 	}
 
-	TempoMap::BBTPointList::const_iterator i;
+	std::vector<TempoMap::BBTPoint>::const_iterator i;
 	Timecode::BBT_Time lower_beat, upper_beat; // the beats at each end of the ruler
+	framecnt_t beat_before_lower_pos = _session->tempo_map().frame_at_beat (floor(_session->tempo_map().beat_at_frame (lower)));
+	framecnt_t beat_after_upper_pos = _session->tempo_map().frame_at_beat (floor (_session->tempo_map().beat_at_frame (upper)) + 1.0);
 
-	_session->bbt_time (lower, lower_beat);
-	_session->bbt_time (upper, upper_beat);
+	_session->bbt_time (beat_before_lower_pos, lower_beat);
+	_session->bbt_time (beat_after_upper_pos, upper_beat);
 	uint32_t beats = 0;
 
 	bbt_accent_modulo = 1;
@@ -1103,19 +1101,21 @@ Editor::compute_bbt_ruler_scale (framepos_t lower, framepos_t upper,
                 bbt_beat_subdivision = 4;
 		break;
 	}
-
-	if (distance (begin, end) == 0) {
+	if (distance (grid.begin(), grid.end()) == 0) {
 		return;
 	}
 
-	i = end;
+	i = grid.end();
 	i--;
-	if ((*i).beat >= (*begin).beat) {
-		bbt_bars = (*i).bar - (*begin).bar;
+
+	/* XX ?? */
+	if ((*i).beat >= (*grid.begin()).beat) {
+		bbt_bars = (*i).bar - (*grid.begin()).bar;
 	} else {
-		bbt_bars = (*i).bar - (*begin).bar - 1;
+		bbt_bars = (*i).bar - (*grid.begin()).bar;
 	}
-	beats = distance (begin, end) - bbt_bars;
+
+	beats = distance (grid.begin(), grid.end()) - bbt_bars;
 
 	/* Only show the bar helper if there aren't many bars on the screen */
 	if ((bbt_bars < 2) || (beats < 5)) {
@@ -1140,7 +1140,7 @@ Editor::compute_bbt_ruler_scale (framepos_t lower, framepos_t upper,
 		bbt_ruler_scale =  bbt_show_ticks_detail;
 	}
 
-	if ((bbt_ruler_scale == bbt_show_ticks_detail) && (lower_beat.beats == upper_beat.beats) && (upper_beat.ticks - lower_beat.ticks <= Timecode::BBT_Time::ticks_per_beat / 4)) {
+	if ((bbt_ruler_scale == bbt_show_ticks_detail) && beats < 3) {
 		bbt_ruler_scale =  bbt_show_ticks_super_detail;
 	}
 }
@@ -1161,38 +1161,34 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 		return;
 	}
 
-	TempoMap::BBTPointList::const_iterator i;
+	std::vector<TempoMap::BBTPoint>::const_iterator i;
 
 	char buf[64];
 	gint  n = 0;
 	framepos_t pos;
 	Timecode::BBT_Time next_beat;
-	framepos_t next_beat_pos;
 	uint32_t beats = 0;
 	uint32_t tick = 0;
 	uint32_t skip;
 	uint32_t t;
-	framepos_t frame_skip;
-	double frame_skip_error;
 	double bbt_position_of_helper;
-	double accumulated_error;
 	bool i_am_accented = false;
 	bool helper_active = false;
 	ArdourCanvas::Ruler::Mark mark;
 
-	ARDOUR::TempoMap::BBTPointList::const_iterator begin;
-	ARDOUR::TempoMap::BBTPointList::const_iterator end;
+	std::vector<TempoMap::BBTPoint> grid;
 
-	compute_current_bbt_points (lower, upper, begin, end);
+	compute_current_bbt_points (grid, lower, upper);
 
-	if (distance (begin, end) == 0) {
+	if (distance (grid.begin(), grid.end()) == 0) {
 		return;
 	}
 
 	switch (bbt_ruler_scale) {
 
 	case bbt_show_beats:
-		beats = distance (begin, end);
+
+		beats = distance (grid.begin(), grid.end());
 		bbt_nmarks = beats + 2;
 
 		mark.label = "";
@@ -1200,7 +1196,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 		mark.style = ArdourCanvas::Ruler::Mark::Micro;
 		marks.push_back (mark);
 
-		for (n = 1, i = begin; n < bbt_nmarks && i != end; ++i) {
+		for (n = 1, i = grid.begin(); n < bbt_nmarks && i != grid.end(); ++i) {
 
 			if ((*i).frame < lower && (bbt_bar_helper_on)) {
 				snprintf (buf, sizeof(buf), "<%" PRIu32 "|%" PRIu32, (*i).bar, (*i).beat);
@@ -1228,7 +1224,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 
 	case bbt_show_ticks:
 
-		beats = distance (begin, end);
+		beats = distance (grid.begin(), grid.end());
 		bbt_nmarks = (beats + 2) * bbt_beat_subdivision;
 
 		bbt_position_of_helper = lower + (30 * Editor::get_current_zoom ());
@@ -1240,7 +1236,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 		mark.style = ArdourCanvas::Ruler::Mark::Micro;
 		marks.push_back (mark);
 
-		for (n = 1, i = begin; n < bbt_nmarks && i != end; ++i) {
+		for (n = 1, i = grid.begin(); n < bbt_nmarks && i != grid.end(); ++i) {
 
 			if ((*i).frame < lower && (bbt_bar_helper_on)) {
 				snprintf (buf, sizeof(buf), "<%" PRIu32 "|%" PRIu32, (*i).bar, (*i).beat);
@@ -1265,45 +1261,20 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 			}
 
 			/* Add the tick marks */
+			skip = Timecode::BBT_Time::ticks_per_beat / bbt_beat_subdivision;
+			tick = skip; // the first non-beat tick
+			t = 0;
+			while (tick < Timecode::BBT_Time::ticks_per_beat && (n < bbt_nmarks)) {
 
-			/* Find the next beat */
-			next_beat.beats = (*i).beat;
-			next_beat.bars = (*i).bar;
-			next_beat.ticks = 0;
-
-			if ((*i).meter->divisions_per_bar() > (next_beat.beats + 1)) {
-				  next_beat.beats += 1;
-			} else {
-				  next_beat.bars += 1;
-				  next_beat.beats = 1;
-			}
-
-			next_beat_pos = _session->tempo_map().frame_time(next_beat);
+				next_beat.beats = (*i).beat;
+				next_beat.bars = (*i).bar;
+				next_beat.ticks = tick;
+				pos = _session->tempo_map().frame_time (next_beat);
 
-			frame_skip = (framepos_t) floor (frame_skip_error = (_session->frame_rate() *  60) / (bbt_beat_subdivision * (*i).tempo->beats_per_minute()));
-			frame_skip_error -= frame_skip;
-			skip = (uint32_t) (Timecode::BBT_Time::ticks_per_beat / bbt_beat_subdivision);
-
-			pos = (*i).frame + frame_skip;
-			accumulated_error = frame_skip_error;
-
-			tick = skip;
-
-			for (t = 0; (tick < Timecode::BBT_Time::ticks_per_beat) && (n < bbt_nmarks) && (pos < next_beat_pos) ; pos += frame_skip, tick += skip, ++t) {
-
-			        if (t % bbt_accent_modulo == (bbt_accent_modulo - 1)) {
+				if (t % bbt_accent_modulo == (bbt_accent_modulo - 1)) {
 					i_am_accented = true;
 				}
-
 				mark.label = "";
-
-				/* Error compensation for float to framepos_t*/
-				accumulated_error += frame_skip_error;
-				if (accumulated_error > 1) {
-					pos += 1;
-					accumulated_error -= 1.0f;
-				}
-
 				mark.position = pos;
 
 				if ((bbt_beat_subdivision > 4) && i_am_accented) {
@@ -1313,7 +1284,10 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 				}
 				i_am_accented = false;
 				marks.push_back (mark);
-				n++;
+
+				tick += skip;
+				++t;
+				++n;
 			}
 		}
 
@@ -1321,17 +1295,17 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 
 	case bbt_show_ticks_detail:
 
-		beats = distance (begin, end);
+		beats = distance (grid.begin(), grid.end());
 		bbt_nmarks = (beats + 2) * bbt_beat_subdivision;
 
-		bbt_position_of_helper = lower + (30 * Editor::get_current_zoom ());
+		bbt_position_of_helper = lower + (3 * Editor::get_current_zoom ());
 
 		mark.label = "";
 		mark.position = lower;
 		mark.style = ArdourCanvas::Ruler::Mark::Micro;
 		marks.push_back (mark);
 
-		for (n = 1,   i = begin; n < bbt_nmarks && i != end; ++i) {
+		for (n = 1,   i = grid.begin(); n < bbt_nmarks && i != grid.end(); ++i) {
 
 			if ((*i).frame < lower && (bbt_bar_helper_on)) {
 			        snprintf (buf, sizeof(buf), "<%" PRIu32 "|%" PRIu32, (*i).bar, (*i).beat);
@@ -1356,36 +1330,20 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 			}
 
 			/* Add the tick marks */
+			skip = Timecode::BBT_Time::ticks_per_beat / bbt_beat_subdivision;
+			tick = skip; // the first non-beat tick
 
-			/* Find the next beat */
-
-			next_beat.beats = (*i).beat;
-			next_beat.bars = (*i).bar;
-
-			if ((*i).meter->divisions_per_bar() > (next_beat.beats + 1)) {
-				  next_beat.beats += 1;
-			} else {
-				  next_beat.bars += 1;
-				  next_beat.beats = 1;
-			}
-
-			next_beat_pos = _session->tempo_map().frame_time(next_beat);
-
-			frame_skip = (framepos_t) floor (frame_skip_error = (_session->frame_rate() *  60) / (bbt_beat_subdivision * (*i).tempo->beats_per_minute()));
-			frame_skip_error -= frame_skip;
-			skip = (uint32_t) (Timecode::BBT_Time::ticks_per_beat / bbt_beat_subdivision);
+			t = 0;
+			while (tick < Timecode::BBT_Time::ticks_per_beat && (n < bbt_nmarks)) {
 
-			pos = (*i).frame + frame_skip;
-			accumulated_error = frame_skip_error;
+				next_beat.beats = (*i).beat;
+				next_beat.bars = (*i).bar;
+				next_beat.ticks = tick;
+				pos = _session->tempo_map().frame_time (next_beat);
 
-			tick = skip;
-
-			for (t = 0; (tick < Timecode::BBT_Time::ticks_per_beat) && (n < bbt_nmarks) && (pos < next_beat_pos) ; pos += frame_skip, tick += skip, ++t) {
-
-			        if (t % bbt_accent_modulo == (bbt_accent_modulo - 1)) {
-				        i_am_accented = true;
+				if (t % bbt_accent_modulo == (bbt_accent_modulo - 1)) {
+					i_am_accented = true;
 				}
-
 				if (i_am_accented && (pos > bbt_position_of_helper)){
 				        snprintf (buf, sizeof(buf), "%" PRIu32, tick);
 				} else {
@@ -1393,14 +1351,6 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 				}
 
 				mark.label = buf;
-
-				/* Error compensation for float to framepos_t*/
-				accumulated_error += frame_skip_error;
-				if (accumulated_error > 1) {
-				        pos += 1;
-					accumulated_error -= 1.0f;
-				}
-
 				mark.position = pos;
 
 				if ((bbt_beat_subdivision > 4) && i_am_accented) {
@@ -1409,7 +1359,11 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 					mark.style = ArdourCanvas::Ruler::Mark::Micro;
 				}
 				i_am_accented = false;
-				n++;
+				marks.push_back (mark);
+
+				tick += skip;
+				++t;
+				++n;
 			}
 		}
 
@@ -1417,17 +1371,17 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 
 	case bbt_show_ticks_super_detail:
 
-		beats = distance (begin, end);
+		beats = distance (grid.begin(), grid.end());
 		bbt_nmarks = (beats + 2) * bbt_beat_subdivision;
 
-		bbt_position_of_helper = lower + (30 * Editor::get_current_zoom ());
+		bbt_position_of_helper = lower + (3 * Editor::get_current_zoom ());
 
 		mark.label = "";
 		mark.position = lower;
 		mark.style = ArdourCanvas::Ruler::Mark::Micro;
 		marks.push_back (mark);
 
-		for (n = 1,   i = begin; n < bbt_nmarks && i != end; ++i) {
+		for (n = 1,   i = grid.begin(); n < bbt_nmarks && i != grid.end(); ++i) {
 
 			if ((*i).frame < lower && (bbt_bar_helper_on)) {
 				  snprintf (buf, sizeof(buf), "<%" PRIu32 "|%" PRIu32, (*i).bar, (*i).beat);
@@ -1452,61 +1406,40 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 			}
 
 			/* Add the tick marks */
-
-			/* Find the next beat */
+			skip = Timecode::BBT_Time::ticks_per_beat / bbt_beat_subdivision;
 
 			next_beat.beats = (*i).beat;
 			next_beat.bars = (*i).bar;
+			tick = skip; // the first non-beat tick
+			t = 0;
+			while (tick < Timecode::BBT_Time::ticks_per_beat && (n < bbt_nmarks)) {
 
-			if ((*i).meter->divisions_per_bar() > (next_beat.beats + 1)) {
-				  next_beat.beats += 1;
-			} else {
-				  next_beat.bars += 1;
-				  next_beat.beats = 1;
-			}
-
-			next_beat_pos = _session->tempo_map().frame_time(next_beat);
-
-			frame_skip = (framepos_t) floor (frame_skip_error = (_session->frame_rate() *  60) / (bbt_beat_subdivision * (*i).tempo->beats_per_minute()));
-			frame_skip_error -= frame_skip;
-			skip = (uint32_t) (Timecode::BBT_Time::ticks_per_beat / bbt_beat_subdivision);
-
-			pos = (*i).frame + frame_skip;
-			accumulated_error = frame_skip_error;
-
-			tick = skip;
-
-			for (t = 0; (tick < Timecode::BBT_Time::ticks_per_beat) && (n < bbt_nmarks) && (pos < next_beat_pos) ; pos += frame_skip, tick += skip, ++t) {
-
-				  if (t % bbt_accent_modulo == (bbt_accent_modulo - 1)) {
-					  i_am_accented = true;
-				  }
-
-				  if (pos > bbt_position_of_helper) {
- 					  snprintf (buf, sizeof(buf), "%" PRIu32, tick);
-				  } else {
-					  buf[0] = '\0';
-				  }
+				next_beat.ticks = tick;
+				pos = _session->tempo_map().frame_time (next_beat);
+				if (t % bbt_accent_modulo == (bbt_accent_modulo - 1)) {
+					i_am_accented = true;
+				}
 
-				  mark.label = buf;
+				if (pos > bbt_position_of_helper) {
+					snprintf (buf, sizeof(buf), "%" PRIu32, tick);
+				} else {
+					buf[0] = '\0';
+				}
 
-				  /* Error compensation for float to framepos_t*/
-				  accumulated_error += frame_skip_error;
-				  if (accumulated_error > 1) {
-					  pos += 1;
-					  accumulated_error -= 1.0f;
-				  }
+				mark.label = buf;
+				mark.position = pos;
 
-				  mark.position = pos;
+				if ((bbt_beat_subdivision > 4) && i_am_accented) {
+					mark.style = ArdourCanvas::Ruler::Mark::Minor;
+				} else {
+					mark.style = ArdourCanvas::Ruler::Mark::Micro;
+				}
+				i_am_accented = false;
+				marks.push_back (mark);
 
-				  if ((bbt_beat_subdivision > 4) && i_am_accented) {
-					  mark.style = ArdourCanvas::Ruler::Mark::Minor;
-				  } else {
-					  mark.style = ArdourCanvas::Ruler::Mark::Micro;
-				  }
-				  i_am_accented = false;
-				  marks.push_back (mark);
-				  n++;
+				tick += skip;
+				++t;
+				++n;
 			}
 		}
 
@@ -1523,7 +1456,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 
 	case bbt_show_64:
         		bbt_nmarks = (gint) (bbt_bars / 64) + 1;
-			for (n = 0,   i = begin; i != end && n < bbt_nmarks; i++) {
+			for (n = 0,   i = grid.begin(); i != grid.end() && n < bbt_nmarks; i++) {
 				if ((*i).is_bar()) {
 					if ((*i).bar % 64 == 1) {
 						if ((*i).bar % 256 == 1) {
@@ -1548,7 +1481,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 
 	case bbt_show_16:
        		bbt_nmarks = (bbt_bars / 16) + 1;
-		for (n = 0,  i = begin; i != end && n < bbt_nmarks; i++) {
+		for (n = 0,  i = grid.begin(); i != grid.end() && n < bbt_nmarks; i++) {
 		        if ((*i).is_bar()) {
 			  if ((*i).bar % 16 == 1) {
 			        if ((*i).bar % 64 == 1) {
@@ -1573,7 +1506,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 
 	case bbt_show_4:
 		bbt_nmarks = (bbt_bars / 4) + 1;
-		for (n = 0,   i = begin; i != end && n < bbt_nmarks; ++i) {
+		for (n = 0,   i = grid.begin(); i != grid.end() && n < bbt_nmarks; ++i) {
 		        if ((*i).is_bar()) {
 			  if ((*i).bar % 4 == 1) {
 			        if ((*i).bar % 16 == 1) {
@@ -1599,7 +1532,7 @@ Editor::metric_get_bbt (std::vector<ArdourCanvas::Ruler::Mark>& marks, gdouble l
 	case bbt_show_1:
 //	default:
 	        bbt_nmarks = bbt_bars + 2;
-		for (n = 0,  i = begin; i != end && n < bbt_nmarks; ++i) {
+		for (n = 0,  i = grid.begin(); i != grid.end() && n < bbt_nmarks; ++i) {
 		        if ((*i).is_bar()) {
 			  if ((*i).bar % 4 == 1) {
 				        snprintf (buf, sizeof(buf), "%" PRIu32, (*i).bar);