GUI With GTK Under Linux

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
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, then
• 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
Download and Install GTK(cont)

• Then create a gtkenv.sh
• export LD_LIBRARY_PATH/home/fanfan/local/lib
  
• export PATH/home/fanfan/local/binPATH
• alias ggcc'gcc -Wall -g gtk-config --cflags
  gtk-config --libs'
• Download gqcam-0.8.tar from http//webcam.sorucefo
  rge.net/ make
• start gqcam

6
One Simple Example

• include ltgtk/gtk.hgt (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 ltgtk/gtk.hgt
• 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)

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 aninvisible, 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.org
• Eric Harlow, Developing Linux Applications, New
  Riders
• Raph Levien, raph_at_acm.org
• Peter Mattis, petm_at_xcf.berkeley.edu