meterbridge: handle shift+scroll

2 files changed, 50 insertions, 0 deletions

diff --git a/gtk2_ardour/meterbridge.cc b/gtk2_ardour/meterbridge.cc
index 4731d39b61..99b80fb668 100644
--- a/gtk2_ardour/meterbridge.cc
+++ b/gtk2_ardour/meterbridge.cc
@@ -43,6 +43,7 @@
 
 #include "meterbridge.h"
 
+#include "keyboard.h"
 #include "monitor_section.h"
 #include "public_editor.h"
 #include "ardour_ui.h"
@@ -288,6 +289,51 @@ Meterbridge::on_key_release_event (GdkEventKey* ev)
 	return true;
 }
 
+bool
+Meterbridge::on_scroll_event (GdkEventScroll* ev)
+{
+	switch (ev->direction) {
+	case GDK_SCROLL_LEFT:
+		scroll_left ();
+		return true;
+	case GDK_SCROLL_UP:
+		if (ev->state & Keyboard::TertiaryModifier) {
+			scroll_left ();
+			return true;
+		}
+		return false;
+
+	case GDK_SCROLL_RIGHT:
+		scroll_right ();
+		return true;
+
+	case GDK_SCROLL_DOWN:
+		if (ev->state & Keyboard::TertiaryModifier) {
+			scroll_right ();
+			return true;
+		}
+		return false;
+	}
+
+	return false;
+}
+
+void
+Meterbridge::scroll_left ()
+{
+	Adjustment* adj = scroller.get_hscrollbar()->get_adjustment();
+	/* stupid GTK: can't rely on clamping across versions */
+	scroller.get_hscrollbar()->set_value (max (adj->get_lower(), adj->get_value() - adj->get_step_increment()));
+}
+
+void
+Meterbridge::scroll_right ()
+{
+	Adjustment* adj = scroller.get_hscrollbar()->get_adjustment();
+	/* stupid GTK: can't rely on clamping across versions */
+	scroller.get_hscrollbar()->set_value (min (adj->get_upper(), adj->get_value() + adj->get_step_increment()));
+}
+
 void
 Meterbridge::on_size_request (Gtk::Requisition* r)
 {
diff --git a/gtk2_ardour/meterbridge.h b/gtk2_ardour/meterbridge.h
index 2e231861c7..56ace71aa9 100644
--- a/gtk2_ardour/meterbridge.h
+++ b/gtk2_ardour/meterbridge.h
@@ -107,6 +107,10 @@ class Meterbridge :
 
 	bool on_key_press_event (GdkEventKey*);
 	bool on_key_release_event (GdkEventKey*);
+	bool on_scroll_event (GdkEventScroll*);
+
+	void scroll_left ();
+	void scroll_right ();
 
 	void on_size_allocate (Gtk::Allocation&);
 	void on_size_request (Gtk::Requisition*);