Hacky fix for track height step losing 'grip' on the

track being resized (#4503).


git-svn-id: svn://localhost/ardour2/branches/3.0@12747 d708f5d6-7413-0410-9779-e7cbd77b26cf

gtk2_ardour/editor.cc

@@ -282,6 +282,7 @@ Editor::Editor ()
 	, _region_selection_change_updates_region_list (true)
 	, _following_mixer_selection (false)
 	, _control_point_toggled_on_press (false)
+	, _stepping_axis_view (0)
 {
 	constructed = false;
 
@@ -696,6 +697,8 @@ Editor::Editor ()
 	signal_configure_event().connect (sigc::mem_fun (*ARDOUR_UI::instance(), &ARDOUR_UI::configure_handler));
 	signal_delete_event().connect (sigc::mem_fun (*ARDOUR_UI::instance(), &ARDOUR_UI::exit_on_main_window_close));
 
+	Gtkmm2ext::Keyboard::the_keyboard().ShiftReleased.connect (sigc::mem_fun (*this, &Editor::shift_key_released));
+	
 	/* allow external control surfaces/protocols to do various things */
 
 	ControlProtocol::ZoomToSession.connect (*this, invalidator (*this), boost::bind (&Editor::temporal_zoom_session, this), gui_context());
@@ -5473,3 +5476,8 @@ Editor::popup_control_point_context_menu (ArdourCanvas::Item* item, GdkEvent* ev
 	_control_point_context_menu.popup (event->button.button, event->button.time);
 }
 
+void
+Editor::shift_key_released ()
+{
+	_stepping_axis_view = 0;
+}

gtk2_ardour/editor.h

@@ -470,6 +470,14 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 
 	void get_pointer_position (double &, double &) const;
 
+	TimeAxisView* stepping_axis_view () {
+		return _stepping_axis_view;
+	}
+	
+	void set_stepping_axis_view (TimeAxisView* v) {
+		_stepping_axis_view = v;
+	}
+
   protected:
 	void map_transport_state ();
 	void map_position_change (framepos_t);
@@ -2102,6 +2110,17 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	/** Flag for a bit of a hack wrt control point selection; see set_selected_control_point_from_click */
 	bool _control_point_toggled_on_press;
 
+	/** This is used by TimeAxisView to keep a track of the TimeAxisView that is currently being
+	    stepped in height using Shift-Scrollwheel.  When a scroll event occurs, we do the step on
+	    this _stepping_axis_view if it is non-0 (and we set up this _stepping_axis_view with the
+	    TimeAxisView underneath the mouse if it is 0).  Then Editor resets _stepping_axis_view when
+	    the shift key is released.  In this (hacky) way, pushing shift and moving the scroll wheel
+	    will operate on the same track until shift is released (rather than skipping about to whatever
+	    happens to be underneath the mouse at the time).
+	*/
+	TimeAxisView* _stepping_axis_view;
+	void shift_key_released ();
+
 	friend class Drag;
 	friend class RegionDrag;
 	friend class RegionMoveDrag;

gtk2_ardour/time_axis_view.cc

@@ -48,6 +48,7 @@
 #include "utils.h"
 #include "streamview.h"
 #include "editor_drag.h"
+#include "editor.h"
 
 #include "i18n.h"
 
@@ -317,7 +318,12 @@ TimeAxisView::controls_ebox_scroll (GdkEventScroll* ev)
 	switch (ev->direction) {
 	case GDK_SCROLL_UP:
 		if (Keyboard::modifier_state_equals (ev->state, Keyboard::TertiaryModifier)) {
-			step_height (false);
+			/* See Editor::_stepping_axis_view for notes on this hack */
+			Editor& e = dynamic_cast<Editor&> (_editor);
+			if (!e.stepping_axis_view ()) {
+				e.set_stepping_axis_view (this);
+			}
+			e.stepping_axis_view()->step_height (false);
 			return true;
 		} else if (Keyboard::no_modifiers_active (ev->state)) {
 			_editor.scroll_tracks_up_line();
@@ -327,7 +333,12 @@ TimeAxisView::controls_ebox_scroll (GdkEventScroll* ev)
 
 	case GDK_SCROLL_DOWN:
 		if (Keyboard::modifier_state_equals (ev->state, Keyboard::TertiaryModifier)) {
-			step_height (true);
+			/* See Editor::_stepping_axis_view for notes on this hack */
+			Editor& e = dynamic_cast<Editor&> (_editor);
+			if (!e.stepping_axis_view ()) {
+				e.set_stepping_axis_view (this);
+			}
+			e.stepping_axis_view()->step_height (true);
 			return true;
 		} else if (Keyboard::no_modifiers_active (ev->state)) {
 			_editor.scroll_tracks_down_line();

libs/gtkmm2ext/gtkmm2ext/keyboard.h

@@ -159,6 +159,8 @@ class Keyboard : public sigc::trackable, PBD::Stateful
 	    }
 	};
 
+	sigc::signal0<void> ShiftReleased;
+
   protected:
 	static Keyboard* _the_keyboard;
 

libs/gtkmm2ext/keyboard.cc

@@ -243,6 +243,14 @@ Keyboard::snooper (GtkWidget *widget, GdkEventKey *event)
 		keyval = event->keyval;
 	}
 
+	if (keyval == GDK_Shift_L) {
+		/* There is a special and rather hacky situation in Editor which makes
+		   it useful to know when a shift key has been released, so emit a signal
+		   here (see Editor::_stepping_axis_view)
+		*/
+		ShiftReleased (); /* EMIT SIGNAL */
+	}
+
 	if (event->type == GDK_KEY_PRESS) {
 
 		if (find (state.begin(), state.end(), keyval) == state.end()) {