====== Gtk4 ======

[[https://www.gtk.org/|Gtk]] ([[https://gitlab.gnome.org/GNOME/gtk/|source]]) is a GUI cross-platform toolkit.



===== Build from source =====

  * Official build instructions: [[https://docs.gtk.org/gtk4/building.html]]
  * Source code downloads: [[https://download.gnome.org/sources/]]






<code bash build_gtk4_notes.txt>
# Install
sudo apt install ninja-build
sudo apt install meson # or `pip install meson` if too old

# You might find along the way you need some other dependencies
sudo apt install libgstreamer-plugins-bad1.0-dev

# Need to build Glib first:
# https://download.gnome.org/sources/glib/2.71/glib-2.71.2.tar.xz
# In glib2 source dir:
meson setup builddir
meson compile -c builddir
meson install -c builddir

# Need to build Glib-networking to get TLS
# https://download.gnome.org/sources/glib-networking/2.70/
# sudo apt install gsettings-desktop-schemas-dev
# sudo apt install libproxy-dev
# sudo apt install cmake
# In the glib-networking dir:
meson setup builddir
cd builddir
ninja
ninja install

# For GTK4, in Gtk4 source dir
# Get build options:
meson configure

# To build with `gtk_doc=true` option
pip install gi-docgen 
sudo apt install gir1.2-graphene-1.0 libgraphene-1.0-dev

# Omit prefix to let it install to install to system `/usr/local/`
meson setup -Dgtk_doc=true --prefix $HOME/gtk4 builddir

# Might need to install some deps like libjpeg,  or sudo apt install libgstreamer1.0-dev

cd builddir
ninja

# Documentation will now be in docs/
# For example: gtk-4.6.1/docs/reference/gtk/gtk4/index.html

# There are examples in source under examples/ directory 

# Install to prefix (use `sudo` if doing system install)
ninja install


</code>


===== Documentation =====


**Offline**

There is example code in the ''examples/'' directory of the source. If you built from source and included the docs with the build, there will also be nice HTML pages in the ''docs/'' directory.

    * API documentation - ''index.html'' - e.g. ''gtk-4.6.1/docs/reference/gtk/gtk4/index.html''
    * Widget gallery: ''visual_index.html'' - e.g. ''gtk-4.6.1/docs/reference/gtk/gtk4/visual_index.html''
    * Example code: ''examples/'' directory - e.g. ''gtk-4.6.1/examples/''

**Online**

    * API documentation: [[https://docs.gtk.org/gtk4/index.html]]
    * Widget gallery: [[https://docs.gtk.org/gtk4/visual_index.html]]
    * Example code: [[https://gitlab.gnome.org/GNOME/gtk/-/tree/main/examples]]

===== Hello world =====

Example ''Makefile'':

<code make Makefile>
all: main

main: main.c
	gcc `pkg-config --cflags gtk4` main.c `pkg-config --libs gtk4`

clean:
	rm a.out
</code>

<code c main.c>
// From https://www.gtk.org/
#include <gtk/gtk.h>

static void on_activate (GtkApplication *app) {
  // Create a new window
  GtkWidget *window = gtk_application_window_new (app);
  // Create a new button
  GtkWidget *button = gtk_button_new_with_label ("Hello, World!");
  // When the button is clicked, close the window passed as an argument
  g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_window_close), window);
  gtk_window_set_child (GTK_WINDOW (window), button);
  gtk_window_present (GTK_WINDOW (window));
}

int main (int argc, char *argv[]) {
  // Create a new application
  GtkApplication *app = gtk_application_new ("com.example.GtkApplication",
                                             G_APPLICATION_FLAGS_NONE);
  g_signal_connect (app, "activate", G_CALLBACK (on_activate), NULL);
  return g_application_run (G_APPLICATION (app), argc, argv);
}
</code>

===== gtkmm (C++) =====

You can use [[http://www.gtkmm.org/en/|gtkmm]] to write C++ code instead of C. On their wiki they have  [[https://developer-old.gnome.org/gtkmm-tutorial/stable/|tutorials]] and [[https://developer-old.gnome.org/gtkmm-tutorial/stable/sec-install-unix-and-linux.html.en|build instructions]] for the [[https://download.gnome.org/sources/gtkmm/|source code]].

You might need some other dependencies like:

  * sigc++-3.0
  * gtk4
  * glibmm-2.68
  * cairomm-1.16
  * pangomm-2.48


To build from source:


<code bash>
# Install mm-common
sudo apt install mm-common

# Build and install libsigc++3
# https://github.com/libsigcplusplus/libsigcplusplus
wget https://github.com/libsigcplusplus/libsigcplusplus/releases/download/3.2.0/libsigc++-3.2.0.tar.xz
tar xzf libsigc++-3.2.0
cd libsigc++-3.2.0
cmake .
./autogen.sh --prefix=/usr/local --enable-static
make
sudo make install

# glibmm
# https://gitlab.gnome.org/GNOME/glibmm
wget https://gitlab.gnome.org/GNOME/glibmm/-/archive/2.70.0/glibmm-2.70.0.tar.gz
tar xzf glibmm-2.70.0.tar.gz
cd glibmm-2.70.0
./autogen.sh --prefix=/usr/local --enable-static
make
sudo make install

# cairomm
# https://www.cairographics.org/releases/
wget https://www.cairographics.org/releases/cairomm-1.16.1.tar.xz
tar xBf cairomm-1.16.1.tar.xz
cd cairomm-1.16.1
./autogen.sh --prefix=/usr/local --enable-static
make
sudo make install

# pangomm
# https://gitlab.gnome.org/GNOME/pangomm
wget https://gitlab.gnome.org/GNOME/pangomm/-/archive/2.50.0/pangomm-2.50.0.tar.gz
tar xzf pangomm-2.50.0.tar.gz
cd pangomm-2.50.0
./autogen.sh --prefix=/usr/local --enable-static
make
sudo make install


# gtkmm
wget https://download.gnome.org/sources/gtkmm/4.6/gtkmm-4.6.0.tar.xz
tar xBf gtkmm-4.6.0.tar.xz
cd gtkmm-4.6.0
./autogen.sh --prefix=/usr/local --enable-static
make
sudo make install

</code>



When compiling, use ''-std=c++20'' flag. When running, you may need to set LD_LIBRARY_PATH if you installed to a special prefix. Maybe able to add ''-static'' if you built all libs with ''--enable-static' configuration and a ''.a'' file is in the lib dir.

<code bash>
# Compile app with gtk4
g++ main.cpp `pkg-config gtkmm-4.0 --cflags --libs` -std=c++20

# Set path for shared library when running
LD_LIBRARY_PATH=/usr/local/lib ./a.out
</code>

Here is a gtkmm hello world:

<code cpp main.cpp>
// gtkmm4 example

// Compile with:
// g++ main.cpp `pkg-config gtkmm-4.0 --cflags --libs` -std=c++20

// Run with
// LD_LIBRARY_PATH=/usr/local/lib ./a.out
#include <gtkmm.h>

class MyWindow : public Gtk::Window
{
public:
  MyWindow();
};

MyWindow::MyWindow()
{
  set_title("Basic application");
  set_default_size(200, 200);
}

int main(int argc, char* argv[])
{
  auto app = Gtk::Application::create("org.gtkmm.examples.base");

  return app->make_window_and_run<MyWindow>(argc, argv);
}
</code>