Source Code License

Every example in this book — everything under examples/ in the repository, and every listing reproduced in the text — is released under the MIT license. Copy it, change it, and use it in your own programs, commercial or not. You do not have to credit this book, though it is appreciated.

The book’s text is under a different, more restrictive licence; see Book Text Licenses.

Note on the previous edition. Editions up to 0.13 released their sample code under the LGPL v3. Those examples targeted PyGTK and GTK 2 and have been removed; they remain available under the LGPL in this repository’s git history. All the code in this edition is new and is MIT.

The MIT License

Copyright (c) 2008–2026 Peter Gill

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

What this does not cover

The libraries the examples use have their own licences, and they are not MIT:

GTK 4, GLib, GObject, Pango, GdkPixbuf

LGPL v2.1 or later. Linking to them from your own program — which is what PyGObject does — does not require your program to be free software, but modifying the libraries themselves does.

libadwaita

LGPL v2.1 or later.

Cairo

LGPL v2.1 or the Mozilla Public License 1.1, your choice.

GStreamer

LGPL v2.1 or later for the framework. Individual plugins vary, and some encoders and decoders carry patent considerations in some jurisdictions. Check the licence of the specific plugins you ship, particularly if you are distributing a bundle rather than depending on system packages.

WebKitGTK

LGPL v2.1 and BSD.

PySide6, used in Part II

LGPL v3 or a commercial Qt licence. The LGPL option has real conditions attached when you bundle Qt into an application rather than linking against a system copy — read them before you ship one.

If you are shipping a Flatpak, the runtime carries most of this for you and flatpak-builder records the licences of what it built.