GUI With GTK+ Under LinuxGUI With GTK+ Under LinuxFanfan Xiong

Introduction Introduction

GTK+ (GIMP toolkit) : A library for creating graphical user interfaces(GUI)

Two examples developed with GTK+

Other GUI software in Linux

Basic Knowledge of GTK+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.

credited to siva

Download and Install GTK+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

credited to siva

Download and Install GTK+Download and Install GTK+(cont)(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

One Simple Example One Simple Example #include <gtk/gtk.h> (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);}

Example AnalysisExample 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

Signals and CallbacksSignals and Callbacks

GTK is an event driven toolkitPassing of control is done using the idea of

"signals“set up a signal handler to catch these

signals and call the appropriate functiongint gtk_signal_connect( GtkObject *object,

gchar *name, GtkSignalFunc func, gpointer func_data );

Example 2: Hello World!Example 2: Hello World! #include <gtk/gtk.h>

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(); }

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);}

Compiling Hello WorldCompiling Hello World

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

Output of Example 2Output of Example 2

Other GUI Software for LinuxOther 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

Glade in Mandrake Linux 8.1Glade in Mandrake Linux 8.1

KDevelop in Mandrake Linux 8.1KDevelop in Mandrake Linux 8.1

Where to Get More InformationWhere 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@acm.org

Peter Mattis, petm@xcf.berkeley.edu