From 7646f13ca808cb1d993176a739bd324bd0743fa1 Mon Sep 17 00:00:00 2001
From: Hugo Saint-Vignes <hugo.saint-vignes@numworks.com>
Date: Thu, 10 Dec 2020 18:09:56 +0100
Subject: [PATCH] [apps/shared] Fix NaN comparison in isCursorHanging method

---
 apps/shared/function_graph_controller.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/apps/shared/function_graph_controller.cpp b/apps/shared/function_graph_controller.cpp
index 1f59575c3..528013d4d 100644
--- a/apps/shared/function_graph_controller.cpp
+++ b/apps/shared/function_graph_controller.cpp
@@ -130,7 +130,9 @@ bool FunctionGraphController::isCursorHanging() {
   }
   ExpiringPointer<Function> f = functionStore()->modelForRecord(functionStore()->activeRecordAtIndex(indexFunctionSelectedByCursor()));
   Coordinate2D<double> xy = f->evaluateXYAtParameter(m_cursor->t(), context);
-  return xy.x1() != m_cursor->x() || xy.x2() != m_cursor->y();
+  // NaN != Nan returns true, but cursor is not hanging if both values are NaN
+  return (xy.x1() != m_cursor->x() && !(std::isnan(xy.x1()) && std::isnan(m_cursor->x())))
+      || (xy.x2() != m_cursor->y() && !(std::isnan(xy.x2()) && std::isnan(m_cursor->y())));
 }
 
 CurveView * FunctionGraphController::curveView() {