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GUI With GTK+ Under Linux. Fanfan Xiong. 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+.
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GUI With GTK+ Under Linux Fanfan Xiong
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+ • 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.
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+(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 credited to siva
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 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 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 );
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 World • To compile use: gcc -Wall -g helloworld.c -o helloworld `gtk-config --cflags` `gtk-config --libs`
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
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@acm.org • Peter Mattis, petm@xcf.berkeley.edu