egui_css: A Styling Framework for egui (Very very very WIP)

egui_css is an extension for egui, a Rust-based immediate mode GUI library. This framework introduces a cascading style sheet (CSS) approach to styling, allowing developers to define styles declaratively for their egui applications.

https://github.com/user-attachments/assets/9d210ed1-4f1d-4f97-acbe-25f5689ee14b

Features

• Blazing Fast: The css parser is blazing fast
• CSS-Like Syntax: Write styles in a familiar CSS-inspired format, enabling intuitive and organized customization of your UI.

Missing Features

• Layout system, a DOM is required for that, so probably is a good idea if egui_css provide this solution with a BTree 🤔
• Media queries for responsive design.
• Advanced selectors like :hover, :focus, or pseudo-elements. (implemented but not works 😔)
• Animation definitions within stylesheets.
• Some issues with increasing memory 🫠

Supported CSS Rules

The following CSS-like rules are supported:

• width: Sets the width of an element.
• height: Sets the height of an element.
• min-width: Sets the minimum width of an element.
• min-height: Sets the minimum height of an element.
• max-width: Sets the maximum width of an element.
• max-height: Sets the maximum height of an element.
• border-color: Sets the border color.
• border: Sets the border width and color.
• border-width: Sets the width of the border.
• border-radius: Sets the rounding of corners.
• padding: Defines the padding around elements.
• padding-left: Sets the left padding.
• padding-top: Sets the top padding.
• padding-right: Sets the right padding.
• padding-bottom: Sets the bottom padding.
• margin: Defines the margin around elements.
• margin-left: Sets the left margin.
• margin-top: Sets the top margin.
• margin-right: Sets the right margin.
• margin-bottom: Sets the bottom margin.
• cursor: Defines the type of cursor to display.
• cursor-color: Sets the cursor color.
• color: Sets the text color.
• background-color: Sets the background color.
• box-shadow: Sets the shadow around elements.
• column-gap: Sets the gap between columns.
• row-gap: Sets the gap between rows.
• gap: Sets the gap between rows and columns.
• text-overflow: Defines how text overflows.
• transition: Sets the transition duration for animations. (no animate)

TODO List of Properties

The following properties are planned for future support:

• display: Define how elements are displayed (e.g., block, inline).
• position: Control the positioning of elements.
• flex-direction: Define the main axis of flex container elements.
• flex-wrap: Allow wrapping of flex items.
• flex-grow: Define the grow factor for flex items.
• flex-shrink: Define the shrink factor for flex items.
• flex-basis: Define the initial size of a flex item.
• justify-content: Align flex items along the main axis.
• justify-self: Align individual items inside a container.
• align-self: Align a specific item inside a flex container.
• align-items: Align items inside a flex container.
• align-content: Align multiple lines inside a flex container.
• user-select: Control text selection behavior.
• z-index: Control the stack order of elements.
• aspect-ratio: Maintain a specific aspect ratio for elements.
• inset: Control positioning inside a container (e.g., top, left).
• outline: Define the outline of elements.
• font-size: Set the size of the font.
• font-family: Specify the font family.
• font-weight: Define the weight of the font.
• font-style: Define the style of the font (e.g., italic).
• line-height: Set the height of lines of text.
• Your suggestion property 🎉

Getting Started

Prerequisites

• Rust 1.80 or later with the cargo build tool.
• Familiarity with egui basics (see the egui documentation).

Usage

1. Define a Style:

egui_css::change_style(egui_css::StyleSheet::from_css(
    r#"
    .header {
      color: purple;
      padding: 20px;
      background-color: black;
      height: 50px;
    }

    #counter {
      color: green;
      background-color: white;
      padding: 20px;
      margin: 20px;
    }

    #counter:hover {
      color: purple;
    }

    .header:hover {
      color: blue;
    }
"#,
));

2. Apply the StyleSheet:

use egui_css::StyledWidgetExt;

ui.vertical(|ui| {
    ui.add(Label::new("My egui Application").styled().class(".header"));
    if ui
        .add(Button::new("Increment").styled().css_id("counter"))
        .clicked()
    {
        self.age += 1;
    }
    ui.add(
        Label::new(format!("age {}", self.age))
            .styled()
            .class(".text-orange-700"),
    );
    ui.add(Label::new("No styled"));
})

Examples

Check out the examples in the examples/ directory of the repository for more advanced use cases, including:

Run the examples with:

cargo run -p egui_css --example simple

Contributing

We welcome contributions! Whether you have ideas for new features, bug fixes, or documentation improvements, feel free to open an issue or submit a pull request.

How to Contribute

1. Fork the repository.
2. Create a branch for your feature or fix.
3. Open a pull request with a detailed description of the changes.

Join Us

Help us expand egui_css! If you're interested in contributing, here are some ways to get involved:

• Add support for missing CSS properties.
• Improve the documentation and examples.
• Create issues for features or bugs you encounter.
• Share your feedback and suggestions for improvement.

Join us in shaping the future of egui_css and making styling in egui applications more flexible and powerful!