Pulled tempo line stuff out into it's own relatively self-contained class.

Draw tempo lines on time canvas and connect them up all pretty-like to the ruler ticks.
Still needs some visual tweaking, but... they draw!  Finally!


git-svn-id: svn://localhost/ardour2/trunk@2247 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 122 insertions, 0 deletions

diff --git a/gtk2_ardour/tempo_lines.cc b/gtk2_ardour/tempo_lines.cc
new file mode 100644
index 0000000000..daaa2dcd34
--- /dev/null
+++ b/gtk2_ardour/tempo_lines.cc
@@ -0,0 +1,122 @@
+/*
+    Copyright (C) 2002-2007 Paul Davis 
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <libgnomecanvasmm/canvas.h>
+#include <libgnomecanvasmm/group.h>
+#include "tempo_lines.h"
+#include "ardour_ui.h"
+
+
+ArdourCanvas::SimpleLine *
+TempoLines::get_line ()
+{
+	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);
+	}
+
+	return line;
+}
+
+
+void
+TempoLines::hide ()
+{
+	for (Lines::iterator i = _used_lines.begin(); i != _used_lines.end(); ++i) {
+      	(*i)->hide();
+		_free_lines.push_back (*i);
+	}
+	_used_lines.clear ();
+}
+
+
+void
+TempoLines::draw (ARDOUR::TempoMap::BBTPointList& points, double frames_per_unit)
+{
+	ARDOUR::TempoMap::BBTPointList::iterator i;
+	ArdourCanvas::SimpleLine *line;
+	gdouble xpos;
+	double who_cares;
+	double x1, x2, y1, y2, beat_density;
+
+	uint32_t beats = 0;
+	uint32_t bars = 0;
+	uint32_t color;
+
+	_canvas.get_scroll_region (x1, y1, x2, who_cares);
+	_canvas.root()->get_bounds(who_cares, who_cares, who_cares, y2);
+
+	// FIXME use canvas height
+	//y2 = TimeAxisView::hLargest*5000; // five thousand largest tracks should be enough.. :)
+	//y2 = 500000; // five thousand largest tracks should be enough.. :)
+
+	/* get the first bar spacing */
+
+	i = points.end();
+	i--;
+	bars = (*i).bar - (*points.begin()).bar;
+	beats = points.size() - bars;
+
+	beat_density =  (beats * 10.0f) / _canvas.get_width ();
+
+	if (beat_density > 4.0f) {
+		/* if the lines are too close together, they become useless
+		 */
+		return;
+	}
+	
+	for (i = points.begin(); i != points.end(); ++i) {
+
+		switch ((*i).type) {
+		case ARDOUR::TempoMap::Bar:
+			break;
+
+		case ARDOUR::TempoMap::Beat:
+			
+			if ((*i).beat == 1) {
+				color = ARDOUR_UI::config()->canvasvar_MeasureLineBar.get();
+			} else {
+				color = ARDOUR_UI::config()->canvasvar_MeasureLineBeat.get();
+
+				if (beat_density > 2.0) {
+					/* only draw beat lines if the gaps between beats are large.
+					*/
+					break;
+				}
+			}
+
+			xpos = rint((*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();	
+			break;
+		}
+	}
+}
+