Dampen

Declarative UI framework for Rust with Iced backend, hot reloading and advanced styling.

Dampen allows you to define your user interface in XML and render it via Iced.

⚠️ DEVELOPMENT STATUS

Dampen is currently under active development and is NOT ready for production use.

The framework is functional and can be tested for experimentation, learning, and contributing to its development. However, the API is unstable and subject to breaking changes. Features may be incomplete, and there may be bugs or performance issues.

Use Dampen for:

• ✅ Experimentation and learning
• ✅ Contributing to development
• ✅ Testing and providing feedback
• ✅ Prototype applications

Do NOT use Dampen for:

• ❌ Production applications
• ❌ Mission-critical systems
• ❌ Applications requiring API stability

We welcome your feedback and contributions! See CONTRIBUTING.md to get involved.

Features

• ✅ Declarative XML definitions
• ✅ Advanced styling system (themes, classes, state styles)
• ✅ Responsive design with breakpoints (mobile, tablet, desktop)
• ✅ Type-safe event handlers
• ✅ Expression evaluation in XML attributes
• ✅ Full Iced widget support (text, buttons, inputs, layouts, etc.)
• ✅ Radio button groups with single-selection behavior
• ✅ Data binding with #[derive(UiModel)]
• ✅ CLI validation tools for syntax checking
• ✅ Dual-mode architecture: Hot-reload for development, codegen for production
• ✅ Hot-reload support: See UI changes instantly without recompiling

Installation

cargo install dampen-cli

Quick Start

Create a New Project

Use the CLI command to scaffold a new Dampen project:

# Create a new project
dampen new my-app

# Navigate to the project
cd my-app

# Run the application
dampen run

Add New UI Windows

NEW! Quickly scaffold new UI windows with the dampen add command:

# Add a settings window
dampen add --ui settings

# Add a window in custom directory
dampen add --ui order_form --path "src/ui/orders"

This creates:

• settings.rs - Model, handlers, and AppState setup
• settings.dampen - Basic UI layout with data binding example

Then add to src/ui/mod.rs:

pub mod settings;

Benefits:

• ✅ Production-ready code in < 1 second
• ✅ Consistent structure across windows
• ✅ Prevents accidental overwrites
• ✅ Reduces manual boilerplate

See dampen add --help for more options.

Project Validation

# Validate XML syntax and widget names
dampen check

# Build the project
dampen build

# Inspect generated IR
dampen inspect src/ui/window.dampen

Advanced Features

Data Binding

#[derive(UiModel, Default, Serialize, Deserialize, Clone)]
struct Model {
    count: i32,
    name: String,
    items: Vec<TodoItem>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
struct TodoItem {
    id: usize,
    text: String,
    completed: bool,
}

Advanced Theming System

Define themes in src/ui/theme/theme.dampen for complete application theming:

<?xml version="1.0" encoding="UTF-8" ?>
<dampen version="1.0">
    <themes>
        <theme name="light">
            <palette
                primary="#3498db"
                secondary="#2ecc71"
                success="#27ae60"
                warning="#f39c12"
                danger="#e74c3c"
                background="#ecf0f1"
                surface="#ffffff"
                text="#2c3e50"
                text_secondary="#7f8c8d" />
            <typography font_family="Inter, sans-serif" font_size_base="16" />
            <spacing unit="8" />
        </theme>

        <theme name="dark" extends="light">
            <palette
                background="#1a1a2e"
                surface="#16213e"
                text="#eaeaea"
                text_secondary="#a0a0a0" />
        </theme>
    </themes>

    <default_theme name="light" />
    <follow_system enabled="true" />
</dampen>

Runtime Theme Switching:

<button label="Dark Mode" on_click="set_theme('dark')" />
<button label="Light Mode" on_click="set_theme('light')" />

Theme Features:

• Theme Inheritance - Extend themes with extends="base_theme"
• System Detection - Auto-detect dark/light mode with <follow_system enabled="true" />
• Hot-Reload - Edit theme.dampen and see changes instantly in development
• Runtime Switching - Switch themes without restarting

See STYLING.md for complete documentation.

Reusable Style Classes

<styles>
    <style name="btn_primary">
        <base
            background="#3498db"
            color="#ffffff"
            padding="8 16"
            border_radius="6"
            border_width="0" />
        <hover background="#5dade2" />
        <active background="#2874a6" />
        <disabled opacity="0.5" />
    </style>
    
    <style name="btn_danger">
        <base
            background="#e74c3c"
            color="#ffffff"
            padding="8 16"
            border_radius="6" />
        <hover background="#ec7063" />
    </style>
</styles>

<button class="btn_primary" label="Submit" on_click="submit" />
<button class="btn_danger" label="Delete" on_click="delete" />

Available Widgets

Dual-Mode Architecture

Dampen supports two compilation modes optimized for different use cases:

Interpreted Mode (Development)

Enabled by default in development builds

• ✅ Fast iteration: Hot-reload UI changes without recompiling
• ✅ Runtime parsing: XML loaded and parsed at application startup
• ✅ Instant feedback: See changes in <300ms
• ✅ Debugging friendly: Error overlays with detailed messages

# Development mode (automatic)
dampen run

# Debug build (interpreted)
dampen build

Hot-reload example:

use dampen_dev::watch_files;

fn subscription(app: &App) -> Subscription<Message> {
    watch_files(vec![PathBuf::from("src/ui/window.dampen")], "xml")
        .map(|_| Message::ReloadUI)
}

Codegen Mode (Production)

Enabled with --release flag

• ✅ Zero runtime overhead: All XML parsed at compile time
• ✅ Optimal performance: Direct widget construction
• ✅ Smaller binaries: No runtime parser included
• ✅ Build-time validation: Catch errors before deployment

# Release run (codegen)
dampen run --release

# Release build (codegen)
dampen build --release

# Alternative: release command (alias for build --release)
dampen release

How it works:

1. build.rs processes .dampen files at compile time
2. Generated Rust code embedded via macros
3. No runtime XML parsing required

Mode Selection

Mode selection is automatic based on --release flag:

Advanced usage:

# Enable additional features
dampen release --features tokio,logging

# Run tests in release mode
dampen test --release

# Verbose output
dampen build -v

Note: By default, dampen run and dampen build use interpreted mode for fast development. Use --release flag to enable codegen mode for production builds.

Architecture

Crate Structure

crates/
├── dampen-core/           # XML parser, IR, traits (no Iced dependency)
├── dampen-macros/         # Macros #[derive(UiModel)], #[dampen_ui]
├── dampen-iced/           # Iced backend implementation
├── dampen-dev/            # Development mode tooling for Dampen
└── dampen-cli/            # Developer CLI (build, check, inspect)

Core Principles

1. Declarative-First: XML is the source of truth for UI structure

2. Type Safety: No type erasure for messages/state

3. Production Mode: Static code generation for deployments

4. Backend-Agnostic: Core crate has no Iced dependency

5. Test-First: TDD for all features

Examples

See the examples/ directory for progressive demonstrations:

CLI Commands

# Generate production code
dampen build --ui ui --output src/ui_generated.rs

# Validate UI files without running
dampen check --ui ui

# Inspect IR or generated code
dampen inspect --file ui/main.dampen
dampen inspect --file ui/main.dampen --codegen --handlers increment,decrement

Documentation

• API Documentation - Complete Rustdoc
• XML Schema Reference - Widgets and attributes
• Styling Guide - Themes, classes, state styles
• Examples - Progressive example projects

Contributing

We welcome contributions from the community! Whether you're fixing bugs, adding features, improving documentation, or reporting issues, your help is appreciated.

Before contributing, please read our Contributing Guide which covers:

• Code of conduct and community standards
• Setting up your development environment
• Coding standards and style guidelines
• Testing requirements (TDD is mandatory)
• Pull request process and commit message format
• How to report issues and request features

Quick start for contributors:

# Fork and clone the repository
git clone https://github.com/YOUR_USERNAME/dampen.git
cd dampen

# Build and test
cargo build --workspace
cargo test --workspace
cargo clippy --workspace -- -D warnings

# Try the examples
dampen run -p hello-world

All contributions must:

• ✅ Pass all tests (cargo test --workspace)
• ✅ Pass clippy lints (cargo clippy --workspace -- -D warnings)
• ✅ Be properly formatted (cargo fmt --all)
• ✅ Include tests for new functionality
• ✅ Update documentation as needed

See docs/CONTRIBUTING.md for complete details.

License

This project is dual-licensed under Apache 2.0 or MIT, at your option.

Built with ❤️ using Rust and Iced