Edifice
Declarative GUI framework for Python and Qt

Edifice is a Python library declarative framework for application user interfaces.

• Modern declarative UI paradigm from web development.
• 100% Python application development, no language inter-op.
• A native Qt desktop app instead of a bundled web browser.
• Fast iteration via hot-reloading.

Edifice uses PySide6 or PyQt6 as a backend. Edifice is like React, but with Python instead of JavaScript, and Qt Widgets instead of the HTML DOM.

If you have React experience, you’ll find Edifice easy to learn. Edifice has function Components, Props, and Hooks just like React.

Getting Started

• Installation

  pip install PySide6-Essentials
  

  pip install pyedifice
  

• Source published at github.com/pyedifice/pyedifice
• Package published at pypi.org/project/pyedifice
• Documentation published at pyedifice.github.io

Why Edifice?

Declarative

Most existing GUI libraries in Python, such as Tkinter and Qt, operate imperatively. To create a dynamic application using these libraries, you must not only think about what widgets to display to the user, but also how to issue the commands to modify the widgets.

With Edifice the developer need only declare what is rendered, not how the content is rendered.

User interactions update the application state, the state renders to a widget tree, and Edifice modifies the existing widget tree to reflect the new state.

Edifice code looks like this:

    number, set_number = use_state(0)

    with VBoxView():
        Button("Add 5", on_click=lambda event: set_number(number+5))
        Label(str(number))
        if number > 30 and number < 70:
            Label("Number is mid")

The GUI displays a button and a label with the current value of number. Clicking the button will add 5 to the number. If the number is “mid” then another label will reveal that fact.

Edifice vs. Qt Quick

Qt Quick is Qt’s declarative GUI framework for Qt.

Qt Quick programs are written in Python + the special QML language + JavaScript.

Edifice programs are written in Python.

Because Edifice programs are only Python, binding to the UI is much more straightforward. Edifice makes it easy to dynamically create, mutate, shuffle, and destroy sections of the UI. Qt Quick assumes a much more static interface.

Qt Quick is like DOM + HTML + JavaScript, whereas Edifice is like React. QML and HTML are both declarative UI languages but they require imperative logic in another language for dynamism. Edifice and React allow fully dynamic applications to be specified declaratively in one language.

How it works

An Edifice component is a render function which declares the mapping from the state to UI. The state of a component is divided into props and state. props are passed to the component in the constructor, whereas state is the component’s own internal state.

Changes to props or state will trigger a re-render of the component. The old and new component trees will be compared to one another, and a diffing algorithm will determine which components previously existed and which ones are new (the algorithm behaves similarly to the React diffing algorithm). Components that previously existed will maintain their state, whereas their props will be updated. Finally, Edifice will issue the minimal update commands to update the UI.

Development Tools

Dynamic hot-reload

Dyanamic hot-reload is very useful for fine-tuning the presentation styles of Elements deep within your application. You can test if the margin should be 10px or 15px instantly without closing the app, reopening it, and waiting for everything to load.

Element Inspector

Similar to the Inspect Elements tool of a browser, the Element Inspector will show you the tree of Elements in a running Edifice application, along with all of the props and state of the Elements.

License

Edifice is MIT Licensed.

Edifice uses Qt under the hood, and both PyQt6 and PySide6 are supported. Note that PyQt6 is distributed with the GPL license while PySide6 is distributed under the more flexible LGPL license.

See PyQt vs PySide Licensing.

Can I use PySide for commercial applications?

Yes, and you don't need to release your source code to customers. The LGPL only requires you to release any changes you make to PySide itself.

Version History / Change Log / Release Notes

See Release Notes (source: versions.rst)

Contribution

Contributions are welcome; please send Pull Requests! See DEVELOPMENT.md for development notes.

When submitting a Pull Request, think about adding tests to tests and adding a line to the Unreleased section of the change log versions.rst.

Poetry Build System

The Poetry pyproject.toml specifies the package dependecies.

Because Edifice supports PySide6 and PyQt6 at the same time, neither are required by [tool.poetry.dependencies]. Instead they are both optional [tool.poetry.group.dev.dependencies]. A project which depends on Edifice should also depend on either PySide6 or PySide6-Essentials or PyQt6.

The requirements.txt is generated by

poetry export -f requirements.txt --output requirements.txt

To use the latest Edifice with a Poetry pyproject.toml from Github instead of PyPI, see Poetry git dependencies, for example:

[tool.poetry.dependencies]
python = ">=3.10,<3.11"
pyedifice = {git = "https://github.com/pyedifice/pyedifice.git"}
PySide6-Essentials = "6.6.2"