1. GUI With GTK+ Under Linux Fanfan Xiong

2. Introduction GTK+ (GIMP toolkit) : A library for creating graphical user interfaces(GUI) Two examples developed with GTK+ Other GUI software in Linux

3. Basic Knowledge of GTK+ GTK is essentially an object oriented application programmers interface (API). Although written completely in C, it is implemented using the idea of classes and callback functions (pointers to functions). GLib: A third component. It contains a few replacements for some standard calls, as well as some additional functions for handling linked lists, etc.

4. credited to siva Download and Install GTK+ Get glib-1.2.10.tar and gtk+-1.2.10.tar from www.gtk.org. copy glib and gtk source gz and untar using xvf, thenwww.gtk.org cd glib*./configure --prefix=/home/fanfan/local make make install export LD_LIBRARY_PATH=/home/fanfan/local/lib cd gtk*./configure --prefix=/home/fanfan/local --with-glib- refix=/home/fanfan/local make make install

5. credited to siva Download and Install GTK+(cont) Then create a gtkenv.sh export LD_LIBRARY_PATH=/home/fanfan/local/lib export PATH=/home/fanfan/local/bin:$PATH alias ggcc='gcc -Wall -g `gtk-config --cflags` `gtk- config --libs`' Download gqcam-0.8.tar from http://webcam.soruceforge.net/ make start gqcam

6. One Simple Example #include (1) int main( int argc, char *argv[] ){ GtkWidget *window; gtk_init (&argc, &argv); (2) window = gtk_window_new (GTK_WINDOW_TOPLEVEL); (3) gtk_widget_show (window); gtk_main (); (4) return(0);}

7. Example Analysis (1) The gtk.h file declares the variables, functions, structures, etc. that will be used in GTK applications. All programs should include gtk/gtk.h (2) This function initializes the library for use, sets up default signal handlers, and checks the arguments passed to your application on the command line (3) create and display a window (4) enters the GTK main processing loop

8. Signals and Callbacks GTK is an event driven toolkit Passing of control is done using the idea of "signals“ set up a signal handler to catch these signals and call the appropriate function gint gtk_signal_connect( GtkObject *object, gchar *name, GtkSignalFunc func, gpointer func_data );

9. Example 2: Hello World! #include void hello( GtkWidget *widget, gpointer data ){ g_print ("Hello World\n"); } gint delete_event( GtkWidget *widget, GdkEvent *event, gpointer data ){ g_print ("delete event occurred\n"); return(TRUE); } void destroy( GtkWidget *widget, gpointer data ){ gtk_main_quit(); }

10. 1. int main( int argc, char *argv[] ){ 2. GtkWidget *window; 3. GtkWidget *button; 4. gtk_init(&argc, &argv); 5. window = gtk_window_new (GTK_WINDOW_TOPLEVEL); 6. gtk_signal_connect (GTK_OBJECT (window), "delete_event", GTK_SIGNAL_FUNC (delete_event), NULL); 7. gtk_signal_connect (GTK_OBJECT (window), "destroy", GTK_SIGNAL_FUNC (destroy), NULL); 8. gtk_container_set_border_width (GTK_CONTAINER (window), 10); 9. button = gtk_button_new_with_label ("Hello World"); 10. gtk_signal_connect (GTK_OBJECT (button), "clicked", GTK_SIGNAL_FUNC (hello), NULL); 11. gtk_signal_connect_object (GTK_OBJECT (button), "clicked", GTK_SIGNAL_FUNC (gtk_widget_destroy), GTK_OBJECT (window)); 12. gtk_container_add (GTK_CONTAINER (window), button); 13. gtk_widget_show (button); 14. gtk_widget_show (window); 15. gtk_main (); 16. return(0);}

11. Compiling Hello World To compile use: gcc -Wall -g helloworld.c -o helloworld `gtk-config --cflags` `gtk-config --libs`

12. Output of Example 2

13. Other GUI Software for Linux Glade : An application for creating graphical user interfaces that use the Gtk+ and GNOME libraries KDevelop: An Integrated Development Environment provides many features that developers need as well as it wraps the functionality of third party projects such as make and the GNU C++ Compilers and makes them an invisible, integrated part of the development process

14. Glade in Mandrake Linux 8.1

15. KDevelop in Mandrake Linux 8.1

16. Where to Get More Information Tony Gale and Ian Main, “GTK+ 1.2 Tutorial”, http://www.gtk.orghttp://www.gtk.org Eric Harlow, “Developing Linux Applications”, New Riders Raph Levien, raph@acm.org Peter Mattis, petm@xcf.berkeley.edu