fpc/packages/gtk1/examples/tutorial/tut3_3.pp

{

  This file extracted from the GTK 1.2 tutorial.
  Section 3.3

  Converted from C to Pascal by Thomas E. Payne
}
program tut3_3;

{$mode objfpc}

uses
 glib,gdk,gtk,sysutils;

procedure callback(widget : pGtkWidget ; data: pgpointer ); cdecl;
begin
  writeln('Hello again - '+pchar(data)+' was pressed');
end;

function delete_event (widget : pGtkWidget ; event: pGdkEvent; data: pgpointer ): integer; cdecl;
begin
  gtk_main_quit();
  delete_event:=0;
end;

var
  window, button, box1 :  pGtkWidget;//GtkWidget is the storage type for widgets

begin
  // This is called in all GTK applications. Arguments are parsed
  // from the command line and are returned to the application.
  gtk_init (@argc, @argv);

  // create a new window
  window := gtk_window_new (GTK_WINDOW_TOPLEVEL);

  // This is a new call, this just sets the title of our
  // new window to "Hello Buttons!" */
  gtk_window_set_title (GTK_WINDOW (window), 'Hello Buttons!');

  // Here we just set a handler for delete_event that immediately
  // exits GTK. */
  gtk_signal_connect (pGTKOBJECT (window), 'delete_event',
                      GTK_SIGNAL_FUNC (@delete_event), NIL);

  // Sets the border width of the window.
  gtk_container_set_border_width (GTK_CONTAINER (window), 10);

  // We create a box to pack widgets into.  This is described in detail
  // in the "packing" section. The box is not really visible, it
  // is just used as a tool to arrange widgets. */
  box1 := gtk_hbox_new(FALSE, 0);

  // Put the box into the main window. */
  gtk_container_add (GTK_CONTAINER (window), box1);

  // Creates a new button with the label "Button 1".
  button := gtk_button_new_with_label ('Button 1');

  // Now when the button is clicked, we call the "callback" function
  // with a pointer to "button 1" as its argument */
  gtk_signal_connect (pGTKOBJECT (button), 'clicked',
                      GTK_SIGNAL_FUNC (@callback), pchar('Button 1'));

    // Instead of gtk_container_add, we pack this button into the invisible
   // box, which has been packed into the window. */
   gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);

  // Always remember this step, this tells GTK that our preparation for
  // this button is complete, and it can now be displayed. */
  gtk_widget_show (button);

  // Do these same steps again to create a second button */
  button := gtk_button_new_with_label ('Button 2');

  // Call the same callback function with a different argument,
  // passing a pointer to "button 2" instead. */
  gtk_signal_connect (GTK_OBJECT (button), 'clicked',
                      GTK_SIGNAL_FUNC (@callback), pchar('Button 2'));

  gtk_box_pack_start(GTK_BOX(box1), button, TRUE, TRUE, 0);

  // The order in which we show the buttons is not really important, but I
  // recommend showing the window last, so it all pops up at once. */
  gtk_widget_show(button);

  gtk_widget_show(box1);


  // and the window
  gtk_widget_show (window);

  // All GTK applications must have a gtk_main(). Control ends here
  // and waits for an event to occur (like a key press or
  // mouse event).
  gtk_main ();
end.