From 67d9fa885a548d8b75ffac74b276a1de38847a37 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 10 Jul 2023 12:22:16 -0600
Subject: [PATCH] use mid-drag key events to allow Alt to force a line break

---
 gtk2_ardour/editor_drag.cc | 28 ++++++++++++++++++++++++++--
 gtk2_ardour/editor_drag.h  |  2 ++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 3522dcba3d..a1808fdaf6 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -7264,6 +7264,7 @@ AutomationDrawDrag::AutomationDrawDrag (Editor* editor, ArdourCanvas::Rectangle&
 	, direction (0)
 	, edge_x (0)
 	, did_snap (false)
+	, line_break_pending (false)
 {
 	DEBUG_TRACE (DEBUG::Drags, "New AutomationDrawDrag\n");
 }
@@ -7344,8 +7345,12 @@ AutomationDrawDrag::maybe_add_point (GdkEvent* ev, timepos_t const & cpos)
 	}
 
 	if (pop_point) {
-		dragging_line->pop_back();
-		drawn_points.pop_back ();
+		if (line_break_pending) {
+			line_break_pending = false;
+		} else {
+			dragging_line->pop_back();
+			drawn_points.pop_back ();
+		}
 	}
 
 	if (add_point) {
@@ -7382,3 +7387,22 @@ void
 AutomationDrawDrag::aborted (bool)
 {
 }
+
+bool
+AutomationDrawDrag::mid_drag_key_event (GdkEventKey* ev)
+{
+	if (ev->type == GDK_KEY_PRESS) {
+		switch (ev->keyval) {
+
+		case GDK_Alt_R:
+		case GDK_Alt_L:
+			line_break_pending = true;
+			return true;
+
+		default:
+			break;
+		}
+	}
+
+	return false;
+}
diff --git a/gtk2_ardour/editor_drag.h b/gtk2_ardour/editor_drag.h
index 640a71eb17..6ae70539a3 100644
--- a/gtk2_ardour/editor_drag.h
+++ b/gtk2_ardour/editor_drag.h
@@ -1592,6 +1592,7 @@ class AutomationDrawDrag : public Drag
 	void motion (GdkEvent*, bool);
 	void finished (GdkEvent*, bool);
 	void aborted (bool);
+	bool mid_drag_key_event (GdkEventKey*);
 
 private:
 	ArdourCanvas::Rectangle& base_rect; /* we do not own this */
@@ -1600,6 +1601,7 @@ private:
 	int edge_x;
 	Evoral::ControlList::OrderedPoints drawn_points;
 	bool did_snap;
+	bool line_break_pending;
 
 	void maybe_add_point (GdkEvent*, Temporal::timepos_t const &);
 };