From e64af8e4ed7e9f69acb5807237b62eff06a0b7a1 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 18 Mar 2024 11:28:16 -0600
Subject: [PATCH] add a test for an environment variable before switching
 canvas single-expose off

---
 libs/canvas/canvas.cc       | 10 ++++++++++
 libs/canvas/canvas/canvas.h |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/libs/canvas/canvas.cc b/libs/canvas/canvas.cc
index 783f3dd678..10ff37196b 100644
--- a/libs/canvas/canvas.cc
+++ b/libs/canvas/canvas.cc
@@ -554,6 +554,16 @@ GtkCanvas::GtkCanvas ()
 		    Gdk::KEY_PRESS_MASK | Gdk::KEY_RELEASE_MASK);
 }
 
+void
+GtkCanvas::set_single_exposure (bool yn)
+{
+	if (g_getenv ("ARDOUR_CANVAS_SINGLE_EXPOSE_ALWAYS")) {
+		yn = true;
+	}
+
+	_single_exposure = yn;
+}
+
 void
 GtkCanvas::use_nsglview (bool retina)
 {
diff --git a/libs/canvas/canvas/canvas.h b/libs/canvas/canvas/canvas.h
index e0d4b66014..f4ad37e920 100644
--- a/libs/canvas/canvas/canvas.h
+++ b/libs/canvas/canvas/canvas.h
@@ -235,7 +235,7 @@ public:
 
 	bool get_mouse_position (Duple& winpos) const;
 
-	void set_single_exposure (bool s) { _single_exposure = s; }
+	void set_single_exposure (bool s);
 	bool single_exposure () { return _single_exposure; }
 
 	void re_enter ();