Fix up modifier behaviour

- its now possible to use snap modifiers in combination with others
	  afaict this hasn't worked for some time.

	- use "contains" rather than "equals" during drag. Still uncertain
	   about this wrt beginning a drag. for now they are all "equals".

	- probably solve the "snap modifier modifier" problem using
	  ArdourKeyboard::indicates_snap () and friend.

gtk2_ardour/editor.cc

@@ -2597,7 +2597,7 @@ Editor::snap_to_with_modifier (framepos_t& start, GdkEvent const * event, RoundM
 		return;
 	}
 
-	if (Keyboard::modifier_state_contains (event->button.state, Keyboard::snap_modifier())) {
+	if (ArdourKeyboard::indicates_snap (event->button.state)) {
 		if (_snap_mode == SnapOff) {
 			snap_to_internal (start, direction, for_mark);
 		}

gtk2_ardour/editor_drag.cc

@@ -339,11 +339,11 @@ Drag::adjusted_current_frame (GdkEvent const * event, bool snap) const
 frameoffset_t
 Drag::snap_delta (GdkEvent const * event) const
 {
-	if (Keyboard::modifier_state_equals (event->button.state, Keyboard::snap_delta_modifier())) {
+	if (ArdourKeyboard::indicates_snap_delta (event->button.state)) {
 		return 0;
-	} else {
-		return _snap_delta;
 	}
+
+	return _snap_delta;
 }
 
 double
@@ -2394,7 +2394,7 @@ NoteResizeDrag::motion (GdkEvent* event, bool /*first_move*/)
 		MidiRegionView* mrv = dynamic_cast<MidiRegionView*>(*r);
 		if (mrv) {
 			double sd = 0.0;
-			if (!Keyboard::modifier_state_equals (event->button.state, Keyboard::snap_delta_modifier())) {
+			if (!ArdourKeyboard::indicates_snap_delta (event->button.state)) {
 				sd = _snap_delta;
 			}
 			mrv->update_resizing (nb, at_front, _drags->current_pointer_x() - grab_x(), relative, sd);
@@ -2411,7 +2411,7 @@ NoteResizeDrag::finished (GdkEvent* event, bool /*movement_occurred*/)
 		assert (nb);
 		MidiRegionView* mrv = dynamic_cast<MidiRegionView*>(*r);
 		double sd = 0.0;
-		if (!Keyboard::modifier_state_equals (event->button.state, Keyboard::snap_delta_modifier())) {
+		if (!ArdourKeyboard::indicates_snap_delta (event->button.state)) {
 			sd = _snap_delta;
 		}
 		if (mrv) {
@@ -2726,7 +2726,7 @@ TrimDrag::motion (GdkEvent* event, bool first_move)
 
 	bool non_overlap_trim = false;
 
-	if (event && Keyboard::modifier_state_equals (event->button.state, ArdourKeyboard::trim_overlap_modifier ())) {
+	if (event && Keyboard::modifier_state_contains (event->button.state, ArdourKeyboard::trim_overlap_modifier ())) {
 		non_overlap_trim = true;
 	}
 
@@ -3736,7 +3736,7 @@ MarkerDrag::motion (GdkEvent* event, bool)
 	framepos_t const newframe = adjusted_current_frame (event);
 	framepos_t next = newframe;
 
-	if (Keyboard::modifier_state_equals (event->button.state, ArdourKeyboard::push_points_modifier ())) {
+	if (Keyboard::modifier_state_contains (event->button.state, ArdourKeyboard::push_points_modifier ())) {
 		move_both = true;
 	}
 
@@ -4003,7 +4003,7 @@ ControlPointDrag::start_grab (GdkEvent* event, Gdk::Cursor* /*cursor*/)
 
 	show_verbose_cursor_text (_point->line().get_verbose_cursor_string (fraction));
 
-	_pushing = Keyboard::modifier_state_contains (event->button.state, ArdourKeyboard::push_points_modifier ());
+	_pushing = Keyboard::modifier_state_equals (event->button.state, ArdourKeyboard::push_points_modifier ());
 
 	if (!_point->can_slide ()) {
 		_x_constrained = true;

gtk2_ardour/keyboard.cc

@@ -235,6 +235,28 @@ ArdourKeyboard::set_state (const XMLNode& node, int version)
 	return Keyboard::set_state (node, version);
 }
 
+bool
+ArdourKeyboard::indicates_snap (guint state)
+{
+	bool contains_s = Keyboard::modifier_state_contains (state, Keyboard::snap_modifier());
+	bool equals_s = Keyboard::modifier_state_equals (state, Keyboard::snap_modifier());
+	bool contains_d = Keyboard::modifier_state_contains (state, Keyboard::snap_delta_modifier());
+	bool equals_d = Keyboard::modifier_state_equals (state, Keyboard::snap_delta_modifier());
+
+	return  (equals_s || (contains_s && ((contains_d && !equals_d) || !contains_d)));
+}
+
+bool
+ArdourKeyboard::indicates_snap_delta (guint state)
+{
+	bool contains_d = Keyboard::modifier_state_contains (state, Keyboard::snap_delta_modifier());
+	bool equals_d = Keyboard::modifier_state_equals (state, Keyboard::snap_delta_modifier());
+	bool contains_s = Keyboard::modifier_state_contains (state, Keyboard::snap_modifier());
+	bool equals_s = Keyboard::modifier_state_equals (state, Keyboard::snap_modifier());
+
+	return (equals_d || (contains_d && ((contains_s && !equals_s) || !contains_s)));
+}
+
 void
 ArdourKeyboard::set_trim_contents_modifier (guint mod)
 {
@@ -296,5 +318,3 @@ ArdourKeyboard::selection_type (guint state)
 		return Selection::Set;
 	}
 }
-
-

gtk2_ardour/keyboard.h

@@ -41,6 +41,9 @@ class ArdourKeyboard : public Gtkmm2ext::Keyboard
 
 	ARDOUR_UI& ui;
 
+	static bool indicates_snap (guint state);
+	static bool indicates_snap_delta (guint state);
+
 	static void set_trim_contents_modifier (guint);
 	/** @return Modifier mask to move contents rather than region bounds during trim;
 	 */

gtk2_ardour/rc_option_editor.cc

@@ -563,7 +563,7 @@ public:
 			}
 		}
 
-		l = manage (left_aligned_label (_("Ignore snap by including:")));
+		l = manage (left_aligned_label (_("Ignore snap using:")));
 		l->set_name ("OptionsLabel");
 
 		t->attach (*l, col, col + 1, row, row + 1, FILL | EXPAND, FILL);