From a1f69ee63bc01c3545c95ed2d9af58f70df235fa Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Sat, 27 Aug 2022 12:54:43 -0600
Subject: [PATCH] canvas: tweaks to Arc canvas item

Cairo uses 0 degrees to mean "east", so the "top" or "north" of
a circle is actually -90 degrees
---
 libs/canvas/arc.cc | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/libs/canvas/arc.cc b/libs/canvas/arc.cc
index e08ea04c03..33f19add78 100644
--- a/libs/canvas/arc.cc
+++ b/libs/canvas/arc.cc
@@ -70,26 +70,29 @@ Arc::compute_bounding_box () const
 void
 Arc::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
 {
-	if (_radius <= 0.0 || _arc_degrees <= 0.0 || (!fill() && !outline())) {
+	if (_radius <= 0.0 || (!fill() && !outline())) {
 		return;
 	}
 
 	Duple c = item_to_window (Duple (_center.x, _center.y));
 
-	context->arc (c.x, c.y, _radius, _start_degrees * (M_PI/180.0), _arc_degrees * (M_PI/180.0));
+	if (_arc_degrees != _start_degrees) {
 
-	if (fill()) {
-		setup_fill_context (context);
-		if (outline()) {
-			context->fill_preserve ();
-		} else {
-			context->fill ();
+		context->arc (c.x, c.y, _radius, _start_degrees * (M_PI/180.0), _arc_degrees * (M_PI/180.0));
+
+		if (fill()) {
+			setup_fill_context (context);
+			if (outline()) {
+				context->fill_preserve ();
+			} else {
+				context->fill ();
+			}
 		}
-	}
 
-	if (outline()) {
-		setup_outline_context (context);
-		context->stroke ();
+		if (outline()) {
+			setup_outline_context (context);
+			context->stroke ();
+		}
 	}
 
 	render_children (area, context);