provide some numerical data during automation trim (range) drags, and correct computation of y-fraction for such drags

git-svn-id: svn://localhost/ardour2/branches/3.0@13011 d708f5d6-7413-0410-9779-e7cbd77b26cf

4 files changed, 76 insertions, 6 deletions

diff --git a/gtk2_ardour/automation_line.cc b/gtk2_ardour/automation_line.cc
index 1c5bfbb4b7..4a21e7905a 100644
--- a/gtk2_ardour/automation_line.cc
+++ b/gtk2_ardour/automation_line.cc
@@ -309,6 +309,31 @@ AutomationLine::get_verbose_cursor_string (double fraction) const
 	return s;
 }
 
+string
+AutomationLine::get_verbose_cursor_relative_string (double original, double fraction) const
+{
+	std::string s = fraction_to_string (fraction);
+	if (_uses_gain_mapping) {
+		s += " dB";
+	}
+
+	std::string d = fraction_to_relative_string (original, fraction);
+
+	if (!d.empty()) {
+
+		s += " (\u0394";
+		s += d;
+
+		if (_uses_gain_mapping) {
+			s += " dB";
+		}
+
+		s += ')';
+	}
+
+	return s;
+}
+
 /**
  *  @param fraction y fraction
  *  @return string representation of this value, using dB if appropriate.
@@ -336,6 +361,45 @@ AutomationLine::fraction_to_string (double fraction) const
 	return buf;
 }
 
+/**
+ *  @param original an old y-axis fraction
+ *  @param fraction the new y fraction
+ *  @return string representation of the difference between original and fraction, using dB if appropriate.
+ */
+string
+AutomationLine::fraction_to_relative_string (double original, double fraction) const
+{
+	char buf[32];
+
+	if (original == fraction) {
+		return "0";
+	}
+
+	if (_uses_gain_mapping) {
+		if (original == 0.0) {
+			/* there is no sensible representation of a relative
+			   change from -inf dB, so return an empty string.
+			*/
+			return "";
+		} else if (fraction == 0.0) {
+			snprintf (buf, sizeof (buf), "-inf");
+		} else {
+			double old_db = accurate_coefficient_to_dB (slider_position_to_gain_with_max (original, Config->get_max_gain()));
+			double new_db = accurate_coefficient_to_dB (slider_position_to_gain_with_max (fraction, Config->get_max_gain()));
+			snprintf (buf, sizeof (buf), "%.1f", new_db - old_db);
+		}
+	} else {
+		view_to_model_coord_y (original);
+		view_to_model_coord_y (fraction);
+		if (EventTypeMap::instance().is_integer (alist->parameter())) {
+			snprintf (buf, sizeof (buf), "%d", (int)fraction - (int)original);
+		} else {
+			snprintf (buf, sizeof (buf), "%.2f", fraction - original);
+		}
+	}
+
+	return buf;
+}
 
 /**
  *  @param s Value string in the form as returned by fraction_to_string.
diff --git a/gtk2_ardour/automation_line.h b/gtk2_ardour/automation_line.h
index b78c2da676..6be7ccd6b8 100644
--- a/gtk2_ardour/automation_line.h
+++ b/gtk2_ardour/automation_line.h
@@ -113,7 +113,9 @@ class AutomationLine : public sigc::trackable, public PBD::StatefulDestructible
 	ArdourCanvas::Item&  grab_item() const { return *line; }
 
 	std::string get_verbose_cursor_string (double) const;
+        std::string get_verbose_cursor_relative_string (double, double) const;
 	std::string fraction_to_string (double) const;
+        std::string fraction_to_relative_string (double, double) const;
 	double string_to_fraction (std::string const &) const;
 	void   view_to_model_coord (double& x, double& y) const;
 	void   view_to_model_coord_y (double &) const;
diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 8a601d25cb..8157011c5a 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -4106,7 +4106,7 @@ AutomationRangeDrag::AutomationRangeDrag (Editor* editor, AutomationTimeAxisView
 	, _nothing_to_drag (false)
 {
 	DEBUG_TRACE (DEBUG::Drags, "New AutomationRangeDrag\n");
-
+	track_view = atv;
 	setup (atv->lines ());
 }
 
@@ -4120,6 +4120,7 @@ AutomationRangeDrag::AutomationRangeDrag (Editor* editor, AudioRegionView* rv, l
 
 	list<boost::shared_ptr<AutomationLine> > lines;
 	lines.push_back (rv->get_gain_line ());
+	track_view = &rv->get_time_axis_view();
 	setup (lines);
 }
 
@@ -4169,6 +4170,7 @@ AutomationRangeDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 	/* Get line states before we start changing things */
 	for (list<Line>::iterator i = _lines.begin(); i != _lines.end(); ++i) {
 		i->state = &i->line->get_state ();
+		i->original_fraction = 1 - ((_drags->current_pointer_y() - track_view->y_position()) / i->line->height());
 	}
 
 	if (_ranges.empty()) {
@@ -4274,7 +4276,7 @@ AutomationRangeDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 	}
 
 	for (list<Line>::iterator i = _lines.begin(); i != _lines.end(); ++i) {
-		i->line->start_drag_multiple (i->points, 1 - (_drags->current_pointer_y() / i->line->height ()), i->state);
+		i->line->start_drag_multiple (i->points, 1 - ((_drags->current_pointer_y() - track_view->y_position()) / i->line->height ()), i->state);
 	}
 }
 
@@ -4285,11 +4287,12 @@ AutomationRangeDrag::motion (GdkEvent*, bool /*first_move*/)
 		return;
 	}
 
-	for (list<Line>::iterator i = _lines.begin(); i != _lines.end(); ++i) {
-		float const f = 1 - (_drags->current_pointer_y() / i->line->height());
+	for (list<Line>::iterator l = _lines.begin(); l != _lines.end(); ++l) {
+		float const f = 1 - ((_drags->current_pointer_y() - track_view->y_position()) / l->line->height());
 
 		/* we are ignoring x position for this drag, so we can just pass in anything */
-		i->line->drag_motion (0, f, true, false);
+		l->line->drag_motion (0, f, true, false);
+		show_verbose_cursor_text (l->line->get_verbose_cursor_relative_string (l->original_fraction, f));
 	}
 }
 
diff --git a/gtk2_ardour/editor_drag.h b/gtk2_ardour/editor_drag.h
index 1579a178a8..6127355965 100644
--- a/gtk2_ardour/editor_drag.h
+++ b/gtk2_ardour/editor_drag.h
@@ -966,10 +966,11 @@ private:
 		std::list<ControlPoint*> points; ///< points to drag on the line
 		std::pair<ARDOUR::framepos_t, ARDOUR::framepos_t> range; ///< the range of all points on the line, in session frames
 		XMLNode* state; ///< the XML state node before the drag
+      	        double original_fraction; ///< initial y-fraction before the drag
 	};
 
 	std::list<Line> _lines;
-
+        TimeAxisView* track_view;
 	bool _nothing_to_drag;
 };