feat: add gtk3 examples

.gitignore

@@ -0,0 +1 @@
+*~

gtk3/mnemonic/exampleapp.c

@@ -0,0 +1,41 @@
+#include <gtk/gtk.h>
+
+void print_msg(GtkWidget *widget, gpointer window) {
+
+  g_print("Button clicked\n");
+}
+
+int main(int argc, char *argv[]) {
+
+  GtkWidget *window;
+  GtkWidget *button;
+
+  gtk_init(&argc, &argv);
+
+  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_title(GTK_WINDOW(window), "Mnemonic");
+  gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
+  gtk_container_set_border_width(GTK_CONTAINER(window), 15);
+
+  /*set mnemonic*/
+  button = gtk_button_new_with_mnemonic("_Button");
+
+  /*connect signal with callback fct print_msg*/
+  g_signal_connect(button, "clicked", 
+      G_CALLBACK(print_msg), NULL);  
+  
+  /*source:https://stackoverflow.com/questions/58746046/alternative-to-deprecated-gtk-alignment-new*/
+  gtk_widget_set_halign (button, GTK_ALIGN_START);
+  gtk_widget_set_valign (button, GTK_ALIGN_START);
+
+  gtk_container_add(GTK_CONTAINER(window), button);
+
+  gtk_widget_show_all(window);
+  
+  g_signal_connect(G_OBJECT(window), "destroy",
+      G_CALLBACK(gtk_main_quit), NULL); 
+
+  gtk_main();
+
+  return 0;
+}

gtk3/mnemonic/makefile

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+CC ?= gcc
+PKGCONFIG = $(shell which pkg-config)
+CFLAGS = $(shell $(PKGCONFIG) --cflags gtk+-3.0)
+LIBS = $(shell $(PKGCONFIG) --libs gtk+-3.0)
+
+SRC = exampleapp.c
+
+OBJS = $(SRC:.c=.o)
+
+all: exampleapp
+
+%.o: %.c
+
+	$(CC) -c -o $(@F) $(CFLAGS) $<
+
+exampleapp: $(OBJS)
+
+	$(CC) -o $(@F) $(OBJS) $(LIBS)
+
+clean:
+
+	rm -f $(OBJS)
+	rm -f exampleapp

gtk3/tooltip/exampleapp.c

@@ -0,0 +1,35 @@
+#include <gtk/gtk.h>
+
+int main(int argc, char *argv[]) {
+
+  GtkWidget *window;
+  GtkWidget *button;
+  GtkWidget *halign;
+
+  gtk_init(&argc, &argv);
+
+  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_title(GTK_WINDOW(window), "Tooltip");
+  gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
+
+  /*set border space around the edges of the window*/
+  gtk_container_set_border_width(GTK_CONTAINER(window), 15);
+  
+  button = gtk_button_new_with_label("Button");
+
+  /*set tooltop for widget*/
+  gtk_widget_set_tooltip_text(button, "Button widget");
+
+  /*source:https://stackoverflow.com/questions/58746046/alternative-to-deprecated-gtk-alignment-new*/
+  gtk_widget_set_halign (button, GTK_ALIGN_START);
+  gtk_widget_set_valign (button, GTK_ALIGN_START);
+
+  gtk_container_add(GTK_CONTAINER(window), button);
+  g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);  
+
+  /*flat the container to show all widgets at once*/
+  gtk_widget_show_all(window);
+  gtk_main();
+
+  return 0;
+}

gtk3/tooltip/makefile

@@ -0,0 +1,23 @@
+CC ?= gcc
+PKGCONFIG = $(shell which pkg-config)
+CFLAGS = $(shell $(PKGCONFIG) --cflags gtk+-3.0)
+LIBS = $(shell $(PKGCONFIG) --libs gtk+-3.0)
+
+SRC = exampleapp.c
+
+OBJS = $(SRC:.c=.o)
+
+all: exampleapp
+
+%.o: %.c
+
+	$(CC) -c -o $(@F) $(CFLAGS) $<
+
+exampleapp: $(OBJS)
+
+	$(CC) -o $(@F) $(OBJS) $(LIBS)
+
+clean:
+
+	rm -f $(OBJS)
+	rm -f exampleapp