Editor-Summary shift rotates scroll direction #10105

gtk2_ardour/editor_summary.cc

@@ -29,6 +29,7 @@
 #include <ytkmm/menuitem.h>
 
 #include "context_menu_helper.h"
+#include "gdk.h"
 #include "streamview.h"
 #include "editor_summary.h"
 #include "gui_thread.h"
@@ -773,7 +774,22 @@ EditorSummary::on_scroll_event (GdkEventScroll* ev)
 	get_editor (&xr);
 	double x = xr.first;
 
-	switch (ev->direction) {
+	GdkScrollDirection direction = ev->direction;
+
+	if (ev->state & Keyboard::TertiaryModifier) {
+		switch (ev->direction) {
+			case GDK_SCROLL_UP:
+				direction = GDK_SCROLL_LEFT;
+				break;
+			case GDK_SCROLL_DOWN:
+				direction = GDK_SCROLL_RIGHT;
+				break;
+			default:
+				break;
+		}
+	}
+
+	switch (direction) {
 		case GDK_SCROLL_UP: {
 
 			summary_zoom_step (-4);