====== Introduzione a Gtkmm ======
Autore: **//Fabio Di Matteo//** \\ Ultima revisione: **//17/02/2018  - 17:01//** \\ \\

<note tip>
 **//  26/04/2023  - 13:40   //**  // //Aggiornamento. \\ Ho scritto uno script che crea lo scheletro dell'applicazione [[programmazione:gtkmm:script_scheletro_applicazione|]]
</note>
{{:programmazione:vala:vala-clickme-count.png?500|}} \\ \\
Gtkmm è l'interfaccia C++ ufficiale del popolare toolkit grafico GTK+. Include le typesafe callback e un completo set di widget facilmente estendibili grazie all'ereditarietà (tratto da wikipedia). \\

In questo tutorial andremo a vedere come realizzare una finestra con un bottone , che al click incrementa il contenuto di una label. Come da figura.
l'interfaccia grafica realizzata con Glade verra' caricata dal file //gui.ui// .

**main.cc**
<code c++>
#include <gtkmm.h>
#include "mainwindow.hpp"

int main(int argc, char *argv[])
{
	auto app = Gtk::Application::create(argc, argv, "org.gtkmm.example");
	mainWindow mainw;
	return app->run(*mainw.window1);
}

</code>

**mainwindow.hpp**
<code c++>
#ifndef MAINWINDOW_HPP
#define MAINWINDOW_HPP

#include <gtkmm.h>

class mainWindow  
{
	public:
		Glib::RefPtr<Gtk::Builder> builder;
		Gtk::Window *window1;
		Gtk::Button *button1;
		Gtk::Label *label1;
		
		mainWindow();
	
	protected:	
		void on_button_clicked();
			
	private:
		/* add your private declarations */
};

#endif /* MAINWINDOW_HPP */ 

</code>

**mainwindow.cpp**
<code c++>

#include "mainwindow.hpp"
#include <iostream>


mainWindow::mainWindow()
{
	auto builder = Gtk::Builder::create();
	
	try
	{
		builder->add_from_file("gui.ui");
	}
	catch(const Glib::FileError& ex)
	{
		std::cerr << "FileError: " << ex.what() << std::endl;
	}
	catch(const Glib::MarkupError& ex)
	{
		std::cerr << "MarkupError: " << ex.what() << std::endl;
	}
	catch(const Gtk::BuilderError& ex)
	{
		std::cerr << "BuilderError: " << ex.what() << std::endl;
	}
	builder->get_widget("window1", window1);
	builder->get_widget("button1", button1);
	builder->get_widget("label1", label1);
	
	button1->signal_clicked().connect( sigc::mem_fun(*this, &mainWindow::on_button_clicked) );
	
}

void mainWindow::on_button_clicked()
{
	static int c;
	c++;
	label1->set_text("You have clicked "+std::to_string(c)+" times!");
}



</code>

**makefile**
<file>
all:
	g++ mainwindow.cpp main.cc `pkg-config gtkmm-3.0 --cflags --libs` -o simple

</file>

**gui.ui**
<code xml>
<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.20.2 -->
<interface>
  <requires lib="gtk+" version="3.20"/>
  <object class="GtkWindow" id="window1">
    <property name="visible">True</property>
    <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="label1">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">You have clicked 0 times</property>
            <attributes>
              <attribute name="scale" value="5"/>
            </attributes>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkButton" id="button1">
            <property name="label" translatable="yes">Cliccami</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">1</property>
          </packing>
        </child>
        <child>
          <placeholder/>
        </child>
      </object>
    </child>
    <child type="titlebar">
      <placeholder/>
    </child>
  </object>
</interface>

</code>

===== Supporto a Meson e alle risorse (GNU/Linux - Windows) =====

La struttura del progetto:
<file>
.
├── compile_resources.sh
├── main.cc
├── mainwindow.cpp
├── mainwindow.hpp
├── meson.build
├── res
│   ├── gui.ui
│   └── resources.xml
└── resources.cpp
</file>

**meson.build**
<file>
project('GTKmm', 'cpp')
gtkmm = dependency('gtkmm-3.0')



os=build_machine.system()
if os == 'linux'
	executable('simple-meson', 'main.cc','resources.cpp','mainwindow.cpp', dependencies : gtkmm)
endif
if os == 'windows'
  executable('simple-meson', 'main.cc','resources.cpp','mainwindow.cpp', dependencies : gtkmm, link_args : ['-mwindows'])
endif

</file>

**main.cpp**
<code cpp>
#include <gtkmm.h>
#include "mainwindow.hpp"

int main(int argc, char *argv[])
{
	auto app = Gtk::Application::create(argc, argv, "org.gtkmm.example");
	mainWindow mainw;
	return app->run(*mainw.window1);
}

</code>



**mainwindow.hpp**
<code cpp>
#ifndef MAINWINDOW_HPP
#define MAINWINDOW_HPP

#include <gtkmm.h>

class mainWindow  
{
	public:
		Glib::RefPtr<Gtk::Builder> builder;
		Gtk::Window *window1;
		Gtk::Button *button1;
		Gtk::Label *label1;
		
		mainWindow();
	
	protected:	
		void on_button_clicked();
			
	private:
		/* add your private declarations */
};

#endif /* MAINWINDOW_HPP */ 

</code>


**mainwindow.cpp**
<code cpp>
#include "mainwindow.hpp"
#include <iostream>


mainWindow::mainWindow()
{
	auto builder = Gtk::Builder::create();
	
	try
	{
		builder->add_from_resource("/app/res/gui.ui");
	}
	catch(const Glib::FileError& ex)
	{
		std::cerr << "FileError: " << ex.what() << std::endl;
	}
	catch(const Glib::MarkupError& ex)
	{
		std::cerr << "MarkupError: " << ex.what() << std::endl;
	}
	catch(const Gtk::BuilderError& ex)
	{
		std::cerr << "BuilderError: " << ex.what() << std::endl;
	}
	
	
	
	
	builder->get_widget("window1", window1);
	builder->get_widget("button1", button1);
	builder->get_widget("label1", label1);
	
	button1->signal_clicked().connect( sigc::mem_fun(*this, &mainWindow::on_button_clicked) );
	
}

void mainWindow::on_button_clicked()
{
	static int c;
	c++;
	label1->set_text("You have clicked "+std::to_string(c)+" times!");
}


</code>

**compile_resources.sh**
<code bash>
#!/bin/bash

cd res
echo "Building resources.cpp ..."
glib-compile-resources --generate-source resources.xml
mv resources.c ../resources.cpp

</code>


**gui.ui**

<code xml>
<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.20.2 -->
<interface>
  <requires lib="gtk+" version="3.20"/>
  <object class="GtkWindow" id="window1">
    <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="label1">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">You have clicked 0 times</property>
            <attributes>
              <attribute name="scale" value="5"/>
            </attributes>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkButton" id="button1">
            <property name="label" translatable="yes">Cliccami</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">1</property>
          </packing>
        </child>
        <child>
          <placeholder/>
        </child>
      </object>
    </child>
    <child>
      <placeholder/>
    </child>
  </object>
</interface>

</code>