clera 0.3.1

Clera — GUI Development with Python 🐍

Clera is a Python GUI framework that lets you build desktop applications quickly and simply — with a low learning curve and minimal boilerplate.

NOTE: Clera is currently in developer beta. Core features are stable and undergoing broader testing before the full public release. To participate in testing or get help, reach out at eirasmx@pm.me

✦ THE BASICS

Installation

pip install clera

Requires Python 3.7+ and PySide6.

Your First Window

Every Clera application starts with a Window. This is the skeleton of any GUI built with Clera:

from clera import Window

window = Window()
# Add your widgets and layouts here
window.run()

Output:

" Why Complicate Simplicity? "

Adding Widgets

Clera widgets are simple, readable Python objects. Here's a basic example with a label and a button:

from clera import Window, Label, Button, Box

def on_click():
    print("Hello from Clera!")

window = Window()
window.add(
    Box([
        Label("Welcome to Clera 👋"),
        Button("Click Me", func=on_click)
    ])
)
window.run()

Layouts

Use Box for vertical/horizontal stacking and Grid for grid-based arrangements:

from clera import Window, Box, Grid, Label

window = Window()
window.add(
    Grid([
        [Label("A"), Label("B")],
        [Label("C"), Label("D")]
    ])
)
window.run()

Styling

Clera uses a CSS-like styling system with its own tag aliases. You can apply styles inline or link an external .cx stylesheet:

window = Window(style="background: #1e1e1e;")

✦ TOOLS

Clera ships with two built-in command-line tools:

Run either from your terminal or command prompt after installing Clera.

✦ PLATFORMS

Hardware

• Desktop and Laptops

OS

• 🪟 Windows
• 🍎 macOS
• 🐧 Linux

📖 Docs: Visit https://clera.readthedocs.io for full documentation and guides.

RELEASE NOTES

v0.3.1 (2026-04-21) - Developer Beta

• Splitter widget with live resize and collapsible panes (added)
• TreeView widget with drag-and-drop, branch editing, and sorting (added)
• SpinBox widget with integer and float modes, prefix and suffix support (added)
• cursor() element with custom image and type support (added)
• Context menu support to Image, List, Select, and Table widgets (added)
• font() helper for loading external font files (added)

• Box() and Grid() now accept css, size, fixed_size, min_size, max_size, and id parameters (added)
• Column() now accepts margin and spacing parameters (added)
• tab() now accepts an id parameter (added)
• Window.run() now accepts instance and child parameters for multi-window support (added)
• Window.fullscreen() method (added)
• Window now accepts alignment, radius, and hide_cursor parameters (added)
• Rounded window mask with radius parameter and live resize support (added)

• Multi-window management via internal window registry (added)
• ensure_window_root() utility for multi-window context resolution (added)
• CSS scoping improvements and alias table pre-compilation for faster parsing (improved)
• MenuBar class renamed from Menubar for consistency (changed)

• Custom exception classes now carry docstrings (improved)
• blob and null database types expanded with proper class bodies (improved)
• Clera Editor layout stabilised; editor auto-runs on import (fixed)