peel provides modern C++ bindings for GObject-based libraries, including the GTK toolkit. It notably makes some different design choices from the existing bindings.

Design goals include:

• zero-cost, no runtime overhead: the C++ wrappers are completely optimized away, the generated machine code is equivalent (or at times better) to what you'd get if you were writing your code in plain C;
• easy to set up, including on Windows;
• only C++11 is required, but some coroutine integration is available if you have C++20;
• full, seamless, first-class support for implementing custom GObject-derived classes, including with deep inheritance;
• faithfully expose GObject concepts (such as initializers and properties);
• most of the wrapper code is automatically generated from GObject introspection data, meaning the API coverage is mostly complete and up-to-date.

peel is a header-only library providing wrappers that are intended to be completely inlined into your code. The peel project consists of two parts: manually written bindings to the few fundamental types (such as GObject::Object), and the code generator, a Python script with no external dependencies, that generates bindings to the majority of the APIs.

Here's a very simple GTK application:

#include <peel/Gtk/Gtk.h>
#include <peel/Gio/ApplicationFlags.h>

using namespace peel;

static void
build_ui (Gio::Application *app)
{
  auto window = Gtk::ApplicationWindow::create (app->cast<Gtk::Application> ());
  auto child = Gtk::Label::create ("Hello world!");
  window->set_child (std::move (child));
  window->present ();
}

int
main (int argc, char **argv)
{
  auto app = Gtk::Application::create ("org.example.App", Gio::Application::Flags::DEFAULT_FLAGS);
  app->connect_activate (build_ui);
  app->run (argc, argv);
}

You need to run the bindings generator, peel-gen, and add its output directory to your include path. When using peel uninstalled, you also need to add the include/ subdirectory from this repository to your include path. bindings.

Use the following template to consume peel in Meson project:

project('example', 'cpp')

gtk = dependency('gtk4')
peel = dependency('peel')

peel_gen = find_program('peel-gen')
peel_gtk = custom_target('peel-codegen',
  command: [
    peel_gen,
    '--recursive',
    '--out-dir', '@OUTDIR@',
    'Gtk', '4.0',
  ],
  output: 'peel',
)

# Add the peel-generated headers as sources to your binary target,
# and specify peel itself, as well as the orignal libraries
# as dependencies.
executable('example',
  'example.cpp',
  peel_gtk,
  dependencies: [gtk, peel],
)

This should work both with a system-wide installation of peel and with peel pulled as a Meson subproject.

You can either use peel uninstalled, which is most useful for consuming it as a Meson subproject, or install it system-wide.

See examples.

Chat on Matrix: #peel:matrix.org

The documentation is hosted in GitLab pages and generated from the docs directory in this repo using mbBook.

The documentation is currently very incomplete, so contributions are welcome!

peel is licensed under the permissive MIT license. Note however that the libraries you use through peel have their own licenses, which you have to follow.