From 11ca9fc89833c02b00ced6212ee251f28be1735d Mon Sep 17 00:00:00 2001
From: Fabien Spindler <Fabien.Spindler@inria.fr>
Date: Fri, 27 Oct 2023 16:46:46 +0200
Subject: [PATCH] Fix build when no display gui available - error reported by
 ros2 jenkins buildfarm

---
 tutorial/image/drawingHelpers.cpp | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/tutorial/image/drawingHelpers.cpp b/tutorial/image/drawingHelpers.cpp
index 9345b1b6aa..98602dc10c 100644
--- a/tutorial/image/drawingHelpers.cpp
+++ b/tutorial/image/drawingHelpers.cpp
@@ -33,25 +33,31 @@
 #include <visp3/core/vpImageConvert.h>
 
 #if defined(VISP_HAVE_X11)
-  vpDisplayX drawingHelpers::d;
+vpDisplayX drawingHelpers::d;
 #elif defined(HAVE_OPENCV_HIGHGUI)
-  vpDisplayOpenCV drawingHelpers::d;
+vpDisplayOpenCV drawingHelpers::d;
 #elif defined(VISP_HAVE_GTK)
-  vpDisplayGTK drawingHelpers::d;
+vpDisplayGTK drawingHelpers::d;
 #elif defined(VISP_HAVE_GDI)
-  vpDisplayGDI drawingHelpers::d;
+vpDisplayGDI drawingHelpers::d;
 #elif defined(VISP_HAVE_D3D9)
-  vpDisplayD3D drawingHelpers::d;
+vpDisplayD3D drawingHelpers::d;
 #endif
 
 vpImage<vpRGBa> drawingHelpers::I_disp;
 
 bool drawingHelpers::display(vpImage<vpRGBa> &I, const std::string &title, const bool &blockingMode)
-{ 
+{
   I_disp = I;
-  d.init(I_disp);
-  vpDisplay::setTitle(I_disp, title.c_str());
-  
+#if defined(VISP_HAVE_DISPLAY)
+  if (!d.isInitialised()) {
+    d.init(I_disp);
+    vpDisplay::setTitle(I_disp, title);
+  }
+#else
+  (void)title;
+#endif
+
   vpDisplay::display(I_disp);
   vpDisplay::displayText(I_disp, 15, 15, "Left click to continue...", vpColor::red);
   vpDisplay::displayText(I_disp, 35, 15, "Right click to stop...", vpColor::red);
@@ -59,21 +65,20 @@ bool drawingHelpers::display(vpImage<vpRGBa> &I, const std::string &title, const
   vpMouseButton::vpMouseButtonType button;
   vpDisplay::getClick(I_disp, button, blockingMode);
   bool hasToContinue = true;
-  if (button == vpMouseButton::button3)
-  {
+  if (button == vpMouseButton::button3) {
     // Right click => stop the program
     hasToContinue = false;
   }
 
   return hasToContinue;
 }
- 
+
 bool drawingHelpers::display(vpImage<unsigned char> &D, const std::string &title, const bool &blockingMode)
 {
   vpImage<vpRGBa> I; // Image to display
   vpImageConvert::convert(D, I);
   return display(I, title, blockingMode);
-} 
+}
 
 bool drawingHelpers::display(vpImage<double> &D, const std::string &title, const bool &blockingMode)
 {