highgui: Make GThread mandatory with GTK

The GThread API is available since more than 11 years with GLib, it is now safe
to assume that it is always available.

CMakeLists.txt

@@ -1465,16 +1465,10 @@ if(WITH_GTK OR HAVE_GTK)
     status("    GTK+:" "YES (ver ${GTK3_VERSION})")
   elseif(HAVE_GTK)
     status("    GTK+:" "YES (ver ${GTK2_VERSION})")
+    status("      GtkGlExt:" HAVE_GTKGLEXT THEN "YES (ver ${GTKGLEXT_VERSION})" ELSE NO)
   else()
     status("    GTK+:" "NO")
   endif()
-
-  if(HAVE_GTK)
-    status(  "      GThread :" HAVE_GTHREAD THEN "YES (ver ${GTHREAD_VERSION})" ELSE NO)
-    if(NOT HAVE_GTK3)
-      status(  "    GtkGlExt:" HAVE_GTKGLEXT THEN "YES (ver ${GTKGLEXT_VERSION})" ELSE NO)
-    endif()
-  endif()
 endif()
 
 if(WITH_FRAMEBUFFER OR HAVE_FRAMEBUFFER)

modules/highgui/CMakeLists.txt

@@ -228,9 +228,6 @@ if(TARGET ocv.3rdparty.gtk3 OR TARGET ocv.3rdparty.gtk2)
     endif()
     list(APPEND highgui_srcs ${CMAKE_CURRENT_LIST_DIR}/src/window_gtk.cpp)
     list(APPEND tgts ${__gtk_dependency})
-    if(TARGET ocv.3rdparty.gthread)
-      list(APPEND tgts ocv.3rdparty.gthread)
-    endif()
     if(TARGET ocv.3rdparty.gtkglext
         AND __gtk_dependency STREQUAL "ocv.3rdparty.gtk2"
         AND NOT OPENCV_GTK_DISABLE_GTKGLEXT
@@ -245,27 +242,18 @@ if(TARGET ocv.3rdparty.gtk3 OR TARGET ocv.3rdparty.gtk2)
     endif()
   elseif("gtk" IN_LIST HIGHGUI_PLUGIN_LIST)
     ocv_create_builtin_highgui_plugin(opencv_highgui_gtk ${__gtk_dependency} "window_gtk.cpp")
-    if(TARGET ocv.3rdparty.gthread)
-      ocv_target_link_libraries(opencv_highgui_gtk ocv.3rdparty.gthread)
-    endif()
     if(TARGET ocv.3rdparty.gtkglext)
       ocv_target_link_libraries(opencv_highgui_gtk ocv.3rdparty.gtkglext)
     endif()
   else()
     if(TARGET ocv.3rdparty.gtk3 AND ("gtk3" IN_LIST HIGHGUI_PLUGIN_LIST OR HIGHGUI_PLUGIN_LIST STREQUAL "all"))
       ocv_create_builtin_highgui_plugin(opencv_highgui_gtk3 ocv.3rdparty.gtk3 "window_gtk.cpp")
-      if(TARGET ocv.3rdparty.gthread)
-        ocv_target_link_libraries(opencv_highgui_gtk3 ocv.3rdparty.gthread)
-      endif()
       if(TARGET ocv.3rdparty.gtkglext)
         ocv_target_link_libraries(opencv_highgui_gtk3 ocv.3rdparty.gtkglext)
       endif()
     endif()
     if(TARGET ocv.3rdparty.gtk2 AND ("gtk2" IN_LIST HIGHGUI_PLUGIN_LIST OR HIGHGUI_PLUGIN_LIST STREQUAL "all"))
       ocv_create_builtin_highgui_plugin(opencv_highgui_gtk2 ocv.3rdparty.gtk2 "window_gtk.cpp")
-      if(TARGET ocv.3rdparty.gthread)
-        ocv_target_link_libraries(opencv_highgui_gtk2 ocv.3rdparty.gthread)
-      endif()
       if(TARGET ocv.3rdparty.gtkglext)
         ocv_target_link_libraries(opencv_highgui_gtk2 ocv.3rdparty.gtkglext)
       endif()

modules/highgui/cmake/detect_gtk.cmake

@@ -1,5 +1,5 @@
 # --- GTK ---
-ocv_clear_vars(HAVE_GTK HAVE_GTK2 HAVE_GTK3 HAVE_GTHREAD HAVE_GTKGLEXT)
+ocv_clear_vars(HAVE_GTK HAVE_GTK2 HAVE_GTK3 HAVE_GTKGLEXT)
 if(WITH_GTK)
   if(NOT WITH_GTK_2_X)
     ocv_check_modules(GTK3 gtk+-3.0)
@@ -20,12 +20,6 @@ if(WITH_GTK)
       endif()
     endif()
   endif()
-  ocv_check_modules(GTHREAD gthread-2.0>=2.32)
-  if(HAVE_GTK AND NOT HAVE_GTHREAD)
-    message(FATAL_ERROR "gthread not found. This library is required when building with GTK support")
-  else()
-    ocv_add_external_target(gthread "${GTHREAD_INCLUDE_DIRS}" "${GTHREAD_LIBRARIES}" "HAVE_GTHREAD")
-  endif()
   if((WITH_OPENGL OR HAVE_OPENGL) AND (HAVE_GTK2 OR HAVE_GTK3))
     if(HAVE_GTK2)
       ocv_check_modules(GTKGLEXT gtkglext-1.0)

modules/highgui/misc/plugins/plugin_gtk/CMakeLists.txt

@@ -50,9 +50,3 @@ elseif(DEFINED GTK_VERSION)
 else()
   message(STATUS "GTK+: YES")
 endif()
-
-if(HAVE_GTHREAD)
-  message(STATUS "GThread : YES (ver ${GTHREAD_VERSION})")
-else()
-  message(STATUS "GThread : NO")
-endif()

modules/highgui/src/window_gtk.cpp

@@ -608,13 +608,11 @@ static gboolean icvOnKeyPress( GtkWidget* widget, GdkEventKey* event, gpointer u
 static void icvOnTrackbar( GtkWidget* widget, gpointer user_data );
 static gboolean icvOnMouse( GtkWidget *widget, GdkEvent *event, gpointer user_data );
 
-#ifdef HAVE_GTHREAD
 int thread_started=0;
 static gpointer icvWindowThreadLoop(gpointer data);
 GMutex*				   last_key_mutex = NULL;
 GCond*				   cond_have_key = NULL;
 GThread*			   window_thread = NULL;
-#endif
 
 static int             last_key = -1;
 
@@ -660,7 +658,6 @@ CV_IMPL int cvInitSystem( int argc, char** argv )
 }
 
 CV_IMPL int cvStartWindowThread(){
-#ifdef HAVE_GTHREAD
     cvInitSystem(0,NULL);
     if (!thread_started)
     {
@@ -676,12 +673,8 @@ CV_IMPL int cvStartWindowThread(){
     }
     thread_started = window_thread!=NULL;
     return thread_started;
-#else
-    return 0;
-#endif
 }
 
-#ifdef HAVE_GTHREAD
 gpointer icvWindowThreadLoop(gpointer /*data*/)
 {
     while(1){
@@ -698,8 +691,6 @@ gpointer icvWindowThreadLoop(gpointer /*data*/)
     return NULL;
 }
 
-#endif
-
 #define CV_LOCK_MUTEX() cv::AutoLock lock(getWindowMutex())
 
 static
@@ -1282,7 +1273,6 @@ static void checkLastWindow()
     // if last window...
     if (getGTKWindows().empty())
     {
-#ifdef HAVE_GTHREAD
         if( thread_started )
         {
             // send key press signal to jump out of any waiting cvWaitKey's
@@ -1290,7 +1280,6 @@ static void checkLastWindow()
         }
         else
         {
-#endif
             // Some GTK+ modules (like the Unity module) use GDBusConnection,
             // which has a habit of postponing cleanup by performing it via
             // idle sources added to the main loop. Since this was the last window,
@@ -1301,9 +1290,7 @@ static void checkLastWindow()
             // thread will process events continuously.
             while( gtk_events_pending() )
                 gtk_main_iteration();
-#ifdef HAVE_GTHREAD
         }
-#endif
     }
 }
 
@@ -1852,7 +1839,6 @@ static gboolean icvOnKeyPress(GtkWidget* widget, GdkEventKey* event, gpointer us
 
     code |= event->state << 16;
 
-#ifdef HAVE_GTHREAD
     if(thread_started)
     {
         g_mutex_lock(last_key_mutex);
@@ -1862,7 +1848,6 @@ static gboolean icvOnKeyPress(GtkWidget* widget, GdkEventKey* event, gpointer us
         g_mutex_unlock(last_key_mutex);
     }
     else
-#endif
     {
         last_key = code;
     }
@@ -2053,7 +2038,6 @@ static gboolean icvAlarm( gpointer user_data )
 
 CV_IMPL int cvWaitKey( int delay )
 {
-#ifdef HAVE_GTHREAD
     if (thread_started && g_thread_self() != window_thread)
     {
         gboolean expired = true;
@@ -2087,7 +2071,6 @@ CV_IMPL int cvWaitKey( int delay )
         return my_last_key;
     }
     else
-#endif
     {
         int expired = 0;
         guint timer = 0;