From d015b55e6bdd5fb923acbd6d5f868be22c8e91d5 Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.alekhin@intel.com>
Date: Wed, 28 Dec 2016 13:06:28 +0300
Subject: [PATCH] highgui: preserve waitKey -1 return value

---
 modules/highgui/src/window.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/highgui/src/window.cpp b/modules/highgui/src/window.cpp
index 9306f8ef5e..35ce8ca265 100644
--- a/modules/highgui/src/window.cpp
+++ b/modules/highgui/src/window.cpp
@@ -218,7 +218,7 @@ int cv::waitKey(int delay)
     if (use_legacy > 0)
         return code;
 #endif
-    return code & 0xff;
+    return (code != -1) ? (code & 0xff) : -1;
 }
 
 int cv::createTrackbar(const String& trackbarName, const String& winName,