From 26ba494083c5a7417177733fa049ca1830271dc7 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Sun, 15 Mar 2015 11:52:28 -0500
Subject: [PATCH] prevent single-axis drags in the editor summary from
 affecting the other axis.

In theory, the EditorSummary::get_editor()/set_editor() calls
should be no-ops if the values are just passed between them,
but this turns out to be not precisely the case. Rather than
figure out exactly how ensure that this is true, mark the
new rect boundaries for the non-moving axis with -1 so that
we know to leave it alone
---
 gtk2_ardour/editor_summary.cc | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/gtk2_ardour/editor_summary.cc b/gtk2_ardour/editor_summary.cc
index 479ab1319c..1ed9af974e 100644
--- a/gtk2_ardour/editor_summary.cc
+++ b/gtk2_ardour/editor_summary.cc
@@ -639,12 +639,16 @@ EditorSummary::on_motion_notify_event (GdkEventMotion* ev)
 			xr.first += dx;
 		} else if (_zoom_position == RIGHT || _zoom_position == RIGHT_TOP || _zoom_position == RIGHT_BOTTOM) {
 			xr.second += dx;
+		} else {
+			xr.first = -1; /* do not change */
 		}
 
 		if (_zoom_position == TOP || _zoom_position == LEFT_TOP || _zoom_position == RIGHT_TOP) {
 			yr.first += dy;
 		} else if (_zoom_position == BOTTOM || _zoom_position == LEFT_BOTTOM || _zoom_position == RIGHT_BOTTOM) {
 			yr.second += dy;
+		} else {
+			yr.first = -1; /* do not change y */
 		}
 
 		set_overlays_dirty ();
@@ -799,8 +803,12 @@ EditorSummary::set_editor (pair<double,double> const x, pair<double, double> con
 		return;
 	}
 
-	set_editor_x (x);
-	set_editor_y (y);
+	if (x.first >= 0) {
+		set_editor_x (x);
+	}
+	if (y.first >= 0) {
+		set_editor_y (y);
+	}
 }
 
 /** Set the left of the x range visible in the editor.
@@ -904,7 +912,7 @@ EditorSummary::set_editor_y (pair<double, double> const y)
 		set_dirty ();
 		return;
 	}
-	
+
 	/* Compute current height of tracks between y.first and y.second.  We add up
 	   the total height into `total_height' and the height of complete tracks into
 	   `scale height'.
@@ -946,7 +954,7 @@ EditorSummary::set_editor_y (pair<double, double> const y)
 	/* Height that we will use for scaling; use the whole editor height unless there are not
 	   enough tracks to fill it.
 	*/
-	double const ch = min (total_height, _editor->visible_canvas_height());
+	double const ch = min (total_height, (_editor->visible_canvas_height() - _editor->get_trackview_group()->canvas_origin().y));
 
 	/* hence required scale factor of the complete tracks to fit the required y range;
 	   the amount of space they should take up divided by the amount they currently take up.