Using QT Theme Engine to Customize Python Desktop GUI | PyQt, PySide, QT Designer, and Qt Sass

QT Theme Engine for Python desktop GUI applications is a powerful tool that allows users to customize the appearance of their applications easily. By using PyQt, PySide, QT Designer, and Qt Sass, developers can create visually appealing interfaces that suit their branding or user preferences.

In this tutorial, we will guide you through the process of creating themes for your PyQt or PySide applications using the QT Theme Engine. We will cover how to install the necessary tools, create a custom theme, and apply it to your application.

Step 1: Install PyQt or PySide
Before you can start using the QT Theme Engine, you need to have PyQt or PySide installed on your system. You can install them using pip:

pip install PyQt5

or

pip install PySide2

Step 2: Install QT Theme Engine
Next, you will need to install the QT Theme Engine library. You can do this by running the following command:

pip install qt-material

This library provides pre-built themes and components that you can use to customize the appearance of your application.

Step 3: Create a Custom Theme
To create a custom theme for your application, you need to define the colors, fonts, and other style properties that you want to use. You can do this by creating a CSS file using Qt Sass, a CSS preprocessor that is compatible with the QT Theme Engine.

Here is an example of a simple theme definition in a CSS file:

@import url("qrc:/qt-material.css");

/* Define custom colors */
:root {
    --primary-color: #3f51b5;
    --secondary-color: #f3f3f3;
    --font-family: "Arial";
}

/* Customize components */
QPushButton {
    background-color: var(--primary-color);
    color: white;
    border: none;
}

QLabel {
    color: var(--primary-color);
}

Step 4: Apply the Custom Theme
Once you have created your custom theme, you can apply it to your application using PyQt or PySide. Here is an example of how you can apply the theme to a PyQt application:

from PyQt5.QtWidgets import QApplication
from qt_material import apply_stylesheet

app = QApplication([])
apply_stylesheet(app, theme="dark_teal.xml")

# Your application code here

In this example, we import the apply_stylesheet function from the qt_material library and pass in the application object (app) and the path to our custom theme file (dark_teal.xml).

Step 5: Run Your Application
Finally, you can run your PyQt or PySide application and see the custom theme in action. Your application should now have a custom appearance that reflects the colors and styles defined in your theme.

By following these steps, you can easily create and apply custom themes to your PyQt or PySide applications using the QT Theme Engine. Experiment with different colors, fonts, and styles to create a unique and visually pleasing user interface for your desktop GUI applications.