Bring back contrained drag modifier with preference setting.

	- this should work as before, but when applied to a button 1 drag,
	  the constraint is in the first direction travelled.

5 files changed, 89 insertions, 21 deletions

diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 014b4679e8..97a24a1a1a 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -249,7 +249,6 @@ Drag::swap_grab (ArdourCanvas::Item* new_item, Gdk::Cursor* cursor, uint32_t /*t
 void
 Drag::start_grab (GdkEvent* event, Gdk::Cursor *cursor)
 {
-	// if dragging with button2, the motion is x constrained, with Alt-button2 it is y constrained
 
 	/* we set up x/y dragging constraints on first move */
 	_x_constrained = false;
@@ -401,20 +400,31 @@ Drag::motion_handler (GdkEvent* event, bool from_autoscroll)
 				/* just changed */
 
 				if (fabs (current_pointer_y() - _grab_y) > fabs (current_pointer_x() - _grab_x)) {
-					if ((event->motion.state & Gdk::BUTTON2_MASK) && Config->get_edit_mode() != Lock) {
-						_x_constrained = true;
-						_y_constrained = false;
-					}
 					_initially_vertical = true;
 				} else {
-					if ((event->motion.state & Gdk::BUTTON2_MASK) && Config->get_edit_mode() != Lock) {
-						_x_constrained = false;
-						_y_constrained = true;
-					}
 					_initially_vertical = false;
 				}
-
-				if (Config->get_edit_mode() == Lock) {
+				if (Config->get_edit_mode() != Lock) {
+					if (event->motion.state & Gdk::BUTTON2_MASK) {
+						// if dragging with button2, the motion is x constrained, with constraint modifier it is y constrained
+						if (Keyboard::modifier_state_equals (event->button.state, ArdourKeyboard::constraint_modifier ())) {
+							_x_constrained = false;
+							_y_constrained = true;
+						} else {
+							_x_constrained = true;
+							_y_constrained = false;
+						}
+					} else if (Keyboard::modifier_state_equals (event->button.state, ArdourKeyboard::constraint_modifier ())) {
+						// if dragging normally, the motion is constrained to the first direction of movement.
+						if (_initially_vertical) {
+							_x_constrained = true;
+							_y_constrained = false;
+						} else {
+							_x_constrained = false;
+							_y_constrained = true;
+						}
+					}
+				} else {
 					if (event->button.state & Gdk::BUTTON2_MASK) {
 						_x_constrained = false;
 					} else {
diff --git a/gtk2_ardour/keyboard.cc b/gtk2_ardour/keyboard.cc
index 8a7c811c3c..bdce6badda 100644
--- a/gtk2_ardour/keyboard.cc
+++ b/gtk2_ardour/keyboard.cc
@@ -48,6 +48,7 @@ accel_map_changed (GtkAccelMap* /*map*/,
 	me->ui.setup_tooltips ();
 }
 
+guint ArdourKeyboard::constraint_mod = Keyboard::SecondaryModifier;
 guint ArdourKeyboard::trim_contents_mod = Keyboard::PrimaryModifier;
 guint ArdourKeyboard::trim_overlap_mod = Keyboard::TertiaryModifier;
 guint ArdourKeyboard::trim_anchored_mod = Keyboard::TertiaryModifier;
@@ -187,6 +188,8 @@ ArdourKeyboard::get_state (void)
 	XMLNode* node = &Keyboard::get_state ();
 	char buf[32];
 
+	snprintf (buf, sizeof (buf), "%d", constraint_mod);
+	node->add_property ("constraint-modifier", buf);
 	snprintf (buf, sizeof (buf), "%d", trim_contents_mod);
 	node->add_property ("trim-contents-modifier", buf);
 	snprintf (buf, sizeof (buf), "%d", trim_overlap_mod);
@@ -208,6 +211,10 @@ ArdourKeyboard::set_state (const XMLNode& node, int version)
 {
 	const XMLProperty* prop;
 
+	if ((prop = node.property ("constraint-modifier")) != 0) {
+		sscanf (prop->value().c_str(), "%d", &constraint_mod);
+	}
+
 	if ((prop = node.property ("trim-contents-modifier")) != 0) {
 		sscanf (prop->value().c_str(), "%d", &trim_contents_mod);
 	}
@@ -256,6 +263,14 @@ ArdourKeyboard::indicates_snap_delta (guint state)
 }
 
 void
+ArdourKeyboard::set_constraint_modifier (guint mod)
+{
+	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~constraint_mod);
+	constraint_mod = mod;
+	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask | constraint_mod);
+}
+
+void
 ArdourKeyboard::set_trim_contents_modifier (guint mod)
 {
 	RelevantModifierKeyMask = GdkModifierType (RelevantModifierKeyMask & ~trim_contents_mod);
diff --git a/gtk2_ardour/keyboard.h b/gtk2_ardour/keyboard.h
index 8ed30efb72..b163bfaa37 100644
--- a/gtk2_ardour/keyboard.h
+++ b/gtk2_ardour/keyboard.h
@@ -44,6 +44,11 @@ class ArdourKeyboard : public Gtkmm2ext::Keyboard
 	static bool indicates_snap (guint state);
 	static bool indicates_snap_delta (guint state);
 
+	static void set_constraint_modifier (guint);
+	/** @return Modifier mask to constrain drags in a particular direction;
+	 */
+	static ModifierMask constraint_modifier () { return ModifierMask (constraint_mod); }
+
 	static void set_trim_contents_modifier (guint);
 	/** @return Modifier mask to move contents rather than region bounds during trim;
 	 */
@@ -74,6 +79,7 @@ class ArdourKeyboard : public Gtkmm2ext::Keyboard
 	 */
 	static ModifierMask note_size_relative_modifier () { return ModifierMask (note_size_relative_mod); }
 private:
+	static guint     constraint_mod;
 	static guint     trim_contents_mod;
 	static guint     trim_overlap_mod;
 	static guint     trim_anchored_mod;
diff --git a/gtk2_ardour/midi_region_view.cc b/gtk2_ardour/midi_region_view.cc
index 4b0c9f54c4..7c74b5f1e0 100644
--- a/gtk2_ardour/midi_region_view.cc
+++ b/gtk2_ardour/midi_region_view.cc
@@ -2800,15 +2800,16 @@ MidiRegionView::update_resizing (NoteBase* primary, bool at_front, double delta_
 		}
 
 		if (!cursor_set) {
-			/* snap delta is in pixels (sigh) */
-			framepos_t delta_samps = trackview.editor().pixel_to_sample (snap_delta);
-			double delta_beats;
+			/* Convert snap delta from pixels to beats. */
+			framepos_t snap_delta_samps = trackview.editor().pixel_to_sample (snap_delta);
+			double snap_delta_beats;
 			int sign = 1;
+
 			/* negative beat offsets aren't allowed */
-			if (delta_samps > 0) {
-				delta_beats = region_frames_to_region_beats_double (delta_samps);
-			} else if (delta_samps < 0) {
-				delta_beats = region_frames_to_region_beats_double ( - delta_samps);
+			if (snap_delta_samps > 0) {
+				snap_delta_beats = region_frames_to_region_beats_double (snap_delta_samps);
+			} else if (snap_delta_samps < 0) {
+				snap_delta_beats = region_frames_to_region_beats_double ( - snap_delta_samps);
 				sign = -1;
 			}
 
@@ -2818,12 +2819,12 @@ MidiRegionView::update_resizing (NoteBase* primary, bool at_front, double delta_
 
 			if (at_front) {
 				if (beats < canvas_note->note()->end_time()) {
-					len = canvas_note->note()->time() - beats + (sign * delta_beats);
+					len = canvas_note->note()->time() - beats + (sign * snap_delta_beats);
 					len += canvas_note->note()->length();
 				}
 			} else {
 				if (beats >= canvas_note->note()->time()) {
-					len = beats - canvas_note->note()->time() - (sign * delta_beats);
+					len = beats - canvas_note->note()->time() - (sign * snap_delta_beats);
 				}
 			}
 
@@ -2878,9 +2879,12 @@ MidiRegionView::commit_resizing (NoteBase* primary, bool at_front, double delta_
 		if (current_x > trackview.editor().sample_to_pixel(_region->length())) {
 			current_x = trackview.editor().sample_to_pixel(_region->length());
 		}
+
+		/* Convert snap delta from pixels to beats with sign. */
 		framepos_t snap_delta_samps = trackview.editor().pixel_to_sample (snap_delta);
 		double snap_delta_beats;
 		int sign = 1;
+
 		if (snap_delta_samps > 0) {
 			snap_delta_beats = region_frames_to_region_beats_double (snap_delta_samps);
 		} else if (snap_delta_samps < 0) {
@@ -2888,7 +2892,7 @@ MidiRegionView::commit_resizing (NoteBase* primary, bool at_front, double delta_
 			sign = -1;
 		}
 
-		/* Convert that to a frame within the source */
+		/* Convert the new x position to a frame within the source */
 		const framepos_t current_fr = snap_pixel_to_sample (current_x, with_snap) + _region->start ();
 
 		/* and then to beats */
diff --git a/gtk2_ardour/rc_option_editor.cc b/gtk2_ardour/rc_option_editor.cc
index a5f4b6e6f1..9b38b558c9 100644
--- a/gtk2_ardour/rc_option_editor.cc
+++ b/gtk2_ardour/rc_option_editor.cc
@@ -453,6 +453,26 @@ public:
 		t->attach (*l, col, col + 1, row, row + 1, FILL | EXPAND, FILL);
 		t->attach (_copy_modifier_combo, col + 1, col + 2, row, row + 1, FILL | EXPAND, FILL);
 
+				++row;
+		col = 1;
+
+		/* constraint modifier */
+		set_popdown_strings (_constraint_modifier_combo, dumb);
+		_constraint_modifier_combo.signal_changed().connect (sigc::mem_fun(*this, &KeyboardOptions::constraint_modifier_chosen));
+
+		for (int x = 0; modifiers[x].name; ++x) {
+			if (modifiers[x].modifier == (guint) ArdourKeyboard::constraint_modifier ()) {
+				_constraint_modifier_combo.set_active_text (S_(modifiers[x].name));
+				break;
+			}
+		}
+
+		l = manage (left_aligned_label (_("Constrain drag using:")));
+		l->set_name ("OptionsLabel");
+
+		t->attach (*l, col, col + 1, row, row + 1, FILL | EXPAND, FILL);
+		t->attach (_constraint_modifier_combo, col + 1, col + 2, row, row + 1, FILL | EXPAND, FILL);
+
 		++row;
 
 		l = manage (left_aligned_label (_("When Beginning a Trim:")));
@@ -763,6 +783,18 @@ private:
 		}
 	}
 
+	void constraint_modifier_chosen ()
+	{
+		string const txt = _constraint_modifier_combo.get_active_text();
+
+		for (int i = 0; modifiers[i].name; ++i) {
+			if (txt == _(modifiers[i].name)) {
+				ArdourKeyboard::set_constraint_modifier (modifiers[i].modifier);
+				break;
+			}
+		}
+	}
+
 	void trim_contents_modifier_chosen ()
 	{
 		string const txt = _trim_contents_combo.get_active_text();
@@ -857,6 +889,7 @@ private:
 	ComboBoxText _insert_note_modifier_combo;
 	ComboBoxText _snap_modifier_combo;
 	ComboBoxText _snap_delta_combo;
+	ComboBoxText _constraint_modifier_combo;
 	ComboBoxText _trim_contents_combo;
 	ComboBoxText _trim_overlap_combo;
 	ComboBoxText _trim_anchored_combo;