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100 lines
3.1 KiB
ObjectPascal
100 lines
3.1 KiB
ObjectPascal
program helloworld2;
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{$mode objfpc} {$H+}
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uses
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Glib2, Gdk2, Gtk2;
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(* Our new improved callback. The data passed to this function
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* is printed to stdout. *)
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procedure callback (widget : PGtkWidget;
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data : gpointer); cdecl;
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begin
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writeln ('Hello again - ', Pgchar (data), ' was pressed');
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end;
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(* another callback *)
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function delete_event (widget: PGtkWidget;
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event : PGdkEvent;
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data : gpointer): gboolean; cdecl;
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begin
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gtk_main_quit;
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delete_event := FALSE;
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end;
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var
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window,
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button,
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box1 : PGtkWidget; (* GtkWidget is the storage type for widgets *)
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begin
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(* This is called in all GTK applications. Arguments are parsed
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* from the command line and are returned to the application. *)
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gtk_init (@argc, @argv);
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(* Create a new window *)
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window := gtk_window_new (GTK_WINDOW_TOPLEVEL);
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(* This is a new call, which just sets the title of our
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* new window to "Hello Buttons!" *)
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gtk_window_set_title (GTK_WINDOW (window), 'Hello Buttons!');
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(* Here we just set a handler for delete_event that immediately
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* exits GTK. *)
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g_signal_connect (G_OBJECT (window), 'delete_event',
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G_CALLBACK (@delete_event), NULL);
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(* Sets the border width of the window. *)
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gtk_container_set_border_width (GTK_CONTAINER (window), 10);
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(* We create a box to pack widgets into. This is described in detail
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* in the "packing" section. The box is not really visible, it
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* is just used as a tool to arrange widgets. *)
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box1 := gtk_hbox_new (FALSE, 0);
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(* Put the box into the main window. *)
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gtk_container_add (GTK_CONTAINER (window), box1);
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(* Creates a new button with the label "Button 1". *)
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button := gtk_button_new_with_label ('Button 1');
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(* Now when the button is clicked, we call the "callback" function
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* with a pointer to "button 1" as its argument *)
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g_signal_connect (G_OBJECT (button), 'clicked',
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G_CALLBACK (@callback), PChar('button 1'));
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(* Instead of gtk_container_add, we pack this button into the invisible
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* box, which has been packed into the window. *)
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gtk_box_pack_start (GTK_BOX(box1), button, TRUE, TRUE, 0);
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(* Always remember this step, this tells GTK that our preparation for
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* this button is complete, and it can now be displayed. *)
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gtk_widget_show (button);
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(* Do these same steps again to create a second button *)
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button := gtk_button_new_with_label ('Button 2');
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(* Call the same callback function with a different argument,
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* passing a pointer to "button 2" instead. *)
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g_signal_connect (G_OBJECT (button), 'clicked',
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G_CALLBACK (@callback), PChar('button 2'));
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gtk_box_pack_start(GTK_BOX (box1), button, TRUE, TRUE, 0);
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(* The order in which we show the buttons is not really important, but I
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* recommend showing the window last, so it all pops up at once. *)
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gtk_widget_show (button);
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gtk_widget_show (box1);
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gtk_widget_show (window);
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(* Rest in gtk_main and wait for the fun to begin! *)
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gtk_main ();
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end.
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