Rayo

Rayo is a declarative, retained-mode UI library for .NET 10.

It is designed for building desktop and cross-platform UI with a code-first model, a retained visual tree, a styling system, and multiple rendering backends.

Highlights

• Declarative UI composition in C#
• Retained-mode rendering pipeline
• Signal-first reactive model
• Fluent API generated from VisualElement properties
• Styling system with selectors, triggers, and transitions
• Multiple rendering backends:
  • Rayo.Rendering.OpenGL
  • Rayo.Rendering.SkiaSharp
  • Rayo.Rendering.Vulkan
• Hosting packages for desktop and Android

Package ecosystem

The repository currently publishes these NuGet packages together:

• Rayo
• Rayo.FluentApiGenerator
• Rayo.Hosting.Abstractions
• Rayo.Hosting.Android
• Rayo.Hosting.Desktop
• Rayo.Rendering
• Rayo.Rendering.OpenGL
• Rayo.Rendering.SkiaSharp
• Rayo.Rendering.Vulkan

All packages in the release set are versioned together from the same Git tag.

Quick example

using Rayo.Controls;
using Rayo.Layout;

var page =
    new VStack()
        .Spacing(12)
        .Padding(24)
        .Children(
            new Label()
                .Text("Hello from Rayo")
                .FontSize(24),
            new Button()
                .Text("Click Me")
                .Height(40)
        );

Repository structure

• Rayo: core UI library
• Rayo.Rendering: rendering contracts and primitives
• Rayo.Rendering.OpenGL: OpenGL backend
• Rayo.Rendering.SkiaSharp: SkiaSharp backend
• Rayo.Rendering.Vulkan: Vulkan backend
• Rayo.Hosting.Desktop: desktop hosting
• Rayo.Hosting.Android: Android hosting
• Samples: sample applications
• Help: technical documentation
• Doc/NUGETS_GENERATION.md: NuGet release guide

Building locally

Restore and build the main library with the repository NuGet configuration:

dotnet restore Rayo/Rayo.csproj --configfile NuGet.Config
dotnet build Rayo/Rayo.csproj --no-restore

The solution file references missing projects in this environment, so direct project builds are the supported path.

Documentation

• Help/ARCHITECTURE.md
• Help/STYLE_ENGINE.md
• Help/FLUENT_EXTENSIONS.md
• Help/SOURCE_GENERATOR_NAMESPACE_MACROS.md

Samples

The repository includes sample applications such as:

• Gallery
• FluentExamples
• StyleDemo
• OpenGLView
• VulkanView
• CrossPlatformApp

License

Rayo is distributed under the MIT License.

See LICENSE for the full text.