From 9e036ed903406f11d875bf73b459222b6b051a28 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Fri, 5 Jul 2019 12:36:40 +0200
Subject: tracker/easy: avoid race & crash on exit

cv::destroyWindow() can't be called along with `cv::imshow()' in
progress from another thread. Moreover, `cv::waitKey()' doesn't work
without any windows present.

Also check for preview enablement to avoid a crash in
`cv::destroyWindow()'.
---
 tracker-easy/tracker-easy.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tracker-easy/tracker-easy.cpp b/tracker-easy/tracker-easy.cpp
index 211eb267..fbc19dea 100644
--- a/tracker-easy/tracker-easy.cpp
+++ b/tracker-easy/tracker-easy.cpp
@@ -88,10 +88,11 @@ namespace EasyTracker
 
     Tracker::~Tracker()
     {
-        cv::destroyWindow("Preview");
-
         iThread.exit();
         iThread.wait();        
+
+        if (iDebug)
+            cv::destroyWindow("Preview");
         
         if (camera)
         {
-- 
cgit v1.2.3