From b6933dbf3a4e27782746c9d12dc91acbf48f5a45 Mon Sep 17 00:00:00 2001
From: Alexander Alekhin <alexander.a.alekhin@gmail.com>
Date: Fri, 5 Feb 2021 23:50:42 +0000
Subject: [PATCH] highgui(pollKey): properly handle no-GUI case

---
 modules/highgui/src/window.cpp       | 16 +++++++++++++++-
 modules/highgui/src/window_QT.cpp    |  7 -------
 modules/highgui/src/window_cocoa.mm  |  7 -------
 modules/highgui/src/window_gtk.cpp   |  7 -------
 modules/highgui/src/window_winrt.cpp |  8 --------
 5 files changed, 15 insertions(+), 30 deletions(-)

diff --git a/modules/highgui/src/window.cpp b/modules/highgui/src/window.cpp
index edf7219..406871b 100644
--- a/modules/highgui/src/window.cpp
+++ b/modules/highgui/src/window.cpp
@@ -297,7 +297,17 @@ int cv::waitKey(int delay)
     return (code != -1) ? (code & 0xff) : -1;
 }
 
-// NOTE: cv::pollKey has no C API equivalent. it is implemented in each backend source file.
+#if defined(HAVE_WIN32UI)
+// pollKey() implemented in window_w32.cpp
+#elif defined(HAVE_GTK) || defined(HAVE_COCOA) || defined(HAVE_QT) || (defined (WINRT) && !defined (WINRT_8_0))
+// pollKey() fallback implementation
+int cv::pollKey()
+{
+    CV_TRACE_FUNCTION();
+    // fallback. please implement a proper polling function
+    return cvWaitKey(1);
+}
+#endif
 
 int cv::createTrackbar(const String& trackbarName, const String& winName,
                    int* value, int count, TrackbarCallback callback,
@@ -789,6 +799,10 @@ CV_IMPL int cvCreateButton(const char*, void (*)(int, void*), void*, int, int)
     CV_NO_GUI_ERROR("cvCreateButton");
 }
 
+int cv::pollKey()
+{
+    CV_NO_GUI_ERROR("cv::pollKey()");
+}
 
 #endif
 
diff --git a/modules/highgui/src/window_QT.cpp b/modules/highgui/src/window_QT.cpp
index 8d89ff0..1600bd9 100644
--- a/modules/highgui/src/window_QT.cpp
+++ b/modules/highgui/src/window_QT.cpp
@@ -382,13 +382,6 @@ CV_IMPL int cvWaitKey(int delay)
 }
 
 
-int cv::pollKey()
-{
-    CV_TRACE_FUNCTION();
-    // fallback. please implement a proper polling function
-    return cvWaitKey(1);
-}
-
 //Yannick Verdie
 //This function is experimental and some functions (such as cvSet/getWindowProperty will not work)
 //We recommend not using this function for now
diff --git a/modules/highgui/src/window_cocoa.mm b/modules/highgui/src/window_cocoa.mm
index 0933a61..29a0278 100644
--- a/modules/highgui/src/window_cocoa.mm
+++ b/modules/highgui/src/window_cocoa.mm
@@ -632,13 +632,6 @@ CV_IMPL int cvWaitKey (int maxWait)
     return returnCode;
 }
 
-int cv::pollKey()
-{
-    CV_TRACE_FUNCTION();
-    // fallback. please implement a proper polling function
-    return cvWaitKey(1);
-}
-
 CvRect cvGetWindowRect_COCOA( const char* name )
 {
     CvRect result = cvRect(-1, -1, -1, -1);
diff --git a/modules/highgui/src/window_gtk.cpp b/modules/highgui/src/window_gtk.cpp
index b2df504..073b340 100644
--- a/modules/highgui/src/window_gtk.cpp
+++ b/modules/highgui/src/window_gtk.cpp
@@ -1950,13 +1950,6 @@ CV_IMPL int cvWaitKey( int delay )
     return last_key;
 }
 
-int cv::pollKey()
-{
-    CV_TRACE_FUNCTION();
-    // fallback. please implement a proper polling function
-    return cvWaitKey(1);
-}
-
 
 #endif  // HAVE_GTK
 #endif  // _WIN32
diff --git a/modules/highgui/src/window_winrt.cpp b/modules/highgui/src/window_winrt.cpp
index ab2e761..1572929 100644
--- a/modules/highgui/src/window_winrt.cpp
+++ b/modules/highgui/src/window_winrt.cpp
@@ -205,14 +205,6 @@ CV_IMPL int cvGetTrackbarPos(const char* trackbar_name, const char* window_name)
 
 /********************************** Not YET implemented API ****************************************************/
 
-int cv::pollKey()
-{
-    CV_TRACE_FUNCTION();
-    CV_WINRT_NO_GUI_ERROR("cvPollKey");
-
-    // TODO: implement appropriate logic here
-}
-
 CV_IMPL int cvWaitKey(int delay)
 {
     CV_WINRT_NO_GUI_ERROR("cvWaitKey");
-- 
2.7.4