Add gtk example

CMakeLists.txt

@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 3.10)
+set(CMAKE_CXX_STANDARD 17)
+
+project(PiCamera)
+
+# Find gtk+-2.0 library
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(GTK2 REQUIRED gtk+-2.0)
+
+add_subdirectory(src)

src/CMakeLists.txt

@@ -0,0 +1,20 @@
+add_executable(
+    JAMCS
+    main.cpp
+)
+target_include_directories(
+    JAMCS
+    PRIVATE
+    ${GTK2_INCLUDE_DIRS}
+)
+target_link_directories(
+    JAMCS
+    PRIVATE
+    ${GTK2_LIBRARY_DIRS}
+)
+target_link_libraries(
+    JAMCS
+    PRIVATE
+    ${GTK2_LIBRARIES}
+)
+add_definitions (${GTK2_CFLAGS_OTHER})

src/main.cpp

@@ -0,0 +1,19 @@
+#include <gtk/gtk.h>
+
+void end_program(GtkWidget *wid, gpointer ptr)
+{
+    gtk_main_quit();
+}
+
+int main(int argc, char* argv[])
+{
+    gtk_init(&argc, &argv);
+    GtkWidget *win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+    GtkWidget *btn = gtk_button_new_with_label("Close Window");
+    g_signal_connect(btn, "clicked", G_CALLBACK(end_program), NULL);
+    g_signal_connect(win, "delete_event", G_CALLBACK(end_program), NULL);
+    gtk_container_add(GTK_CONTAINER(win), btn);
+    gtk_widget_show_all(win);
+    gtk_main();
+    return 0;
+}