====== Hello world in GTK-D  ======

Autore: **//Fabio Di Matteo//** \\ Ultima revisione:  **//  03/07/2025 12:56   //**  // //

<note important>Funziona ancora , ma io userei [[programmazione:d:gid:hello_world|Hello world in gtk4 e linguaggio D usando Gid]]</note>

Un hello world che mostra le basi di una finestra GTK-D . \\

Trovo la documentazione un pochino carente al momento. Mi sono aiutato guardando gli esempi dentro la directory "demos" del 
[[https://github.com/gtkd-developers/GtkD/tree/master|repository ufficiale GtkD]] . In più dato che ho usato dub package manager ho trovato utile dare una sbirciata direttamente al codice sorgente di GTK-D . I file si trovano qui:
<file>ls $HOME/.dub/packages/gtk-d/3.11.0/gtk-d/generated/gtkd/gtk</file>
Altra risorsa utile: [[https://code.dlang.org/packages/gid-gtk4-examples|gid-gtk4-examples]]

===== Una semplice finestra con un bottone =====

<code D>

import gtk.MainWindow;
import gtk.Label;
import gtk.Main;
import gtk.Button;
import std.stdio;

void onClicked(Button b) 
{
   writeln("Cliccato.");
}


void main(string[] args)
{
    Main.init(args);
    MainWindow win = new MainWindow("Hello World");
    win.setDefaultSize(200, 100);
	auto mybtn=new Button();
	mybtn.setLabel("Clicca");
	

	mybtn.addOnClicked(delegate void(Button b){
			onClicked(b);
			b.setLabel("Cliccato.");
	});
	
	win.add(mybtn);
    win.showAll();
    Main.run();
}

</code>


**dub.json**
<code json>
{
	"authors": [
		"fabio"
	],
	"copyright": "Copyright © 2025, fabio",
	"dependencies": {
		"gtk-d": "~>3.11.0"
	},
	"description": "A minimal D application.",
	"license": "GPL-2.0-only",
	"name": "gtk3-builder"
}
</code>

===== Uso di Gtk Builder e Glade =====

**app.d**
<code D>
import gio.Application: GioApplication = Application;

import gtk.Application;
import gtk.ApplicationWindow;
import gtk.Builder;
import gtk.Button;
import gtk.Entry;
import gtk.Label;

import std.stdio;
import core.stdc.stdlib;


int main(string[] args)
{
    auto application = new Application("org.gtkd.demo.builder.builderTest", GApplicationFlags.FLAGS_NONE);
    
    void initGui(GioApplication a) 
    {
    
		auto builder = new Builder();
		
		if( ! builder.addFromFile("gui.ui") ) {
				writeln("Oops, could not create Glade object, check your glade file ;)");
				exit(1);
		}
		auto mywin = cast(ApplicationWindow)builder.getObject("mywin");
		if (mywin is null) 
		{
			writeln("mywin è null");
		}
		mywin.setApplication(application);
		mywin.setTitle("This is a glade application window");
		
		auto mylabel = cast(Label)builder.getObject("mylabel");
		auto myentry = cast(Entry)builder.getObject("myentry");
		auto mybutton = cast(Button)builder.getObject("mybutton");
		
		
		mybutton.addOnClicked(delegate void(Button b){
			string t= myentry.getText();
			if (t!="")
			{
				mylabel.setLabel(t);
			}else{
				mylabel.setLabel("Inserisci il testo nella entry e clicca sul bottone.");
			}	
		});
		
		
		mywin.showAll();
		
	}
	
	
	application.addOnActivate(&initGui);
	return application.run(args);
}

</code>


**gui.ui**
<code xml>
<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.40.0 -->
<interface>
  <requires lib="gtk+" version="3.24"/>
  <object class="GtkApplicationWindow" id="mywin">
    <property name="can-focus">False</property>
    <child>
      <object class="GtkBox">
        <property name="visible">True</property>
        <property name="can-focus">False</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkLabel" id="mylabel">
            <property name="visible">True</property>
            <property name="can-focus">False</property>
            <property name="label" translatable="yes">label</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkEntry" id="myentry">
            <property name="visible">True</property>
            <property name="can-focus">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
        <child>
          <object class="GtkButton" id="mybutton">
            <property name="label" translatable="yes">button</property>
            <property name="visible">True</property>
            <property name="can-focus">True</property>
            <property name="receives-default">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">2</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

</code>

===== Un meson.build =====

Uso il compilatore ldc e lib[g]phobos da gdc.

<code python>
project('simple', 'd',
  version : '0.1',
  default_options : ['buildtype=debugoptimized']
)

gtk_pkg = 'gtk+-3.0'
gtkd_pkg = 'gtkd-3'

gtk = dependency(gtk_pkg, method: 'pkg-config')
gtkd = dependency(gtkd_pkg, method: 'pkg-config')

# se gtkd non è trovato, prova a usare i flags manuali (opzionale)
if not gtkd.found()
  error('gtkD pkg-config dependency "' + gtkd_pkg + '" non trovata. Assicurati che gtkd sia installato e pkg-config veda gtkD-3.0.')
endif

# sorgenti
sources = files('main.d')

# target eseguibile
executable('simple',
  sources,
  dependencies: [gtkd, gtk],
  install: true,
  link_args: ['-Wl,-Bstatic', '-lgphobos', '-Wl,-Bdynamic']
  #d_module_version: '0.1'
)

</code>