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😺 MewUI is a cross-platform and lightweight, code-first .NET GUI framework aimed at NativeAOT.

🧪 Experimental Prototype

Important

This project is a proof-of-concept prototype for validating ideas and exploring design directions.
As it evolves toward v1.0, APIs, internal architecture, and runtime behavior may change significantly.
Backward compatibility is not guaranteed at this stage.

🤖 AI-Assisted Development

Note

This project was developed using an AI prompt–driven workflow.
Design and implementation were performed through iterative prompting without direct manual code edits,
with each step reviewed and refined by the developer.

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🚀 Try It Out

You can run it immediately by entering the following command in the Windows command line or a Linux terminal. (.NET 10 SDK required)

Warning

This command downloads and executes code directly from GitHub.

curl -sL https://raw.githubusercontent.com/aprillz/MewUI/refs/heads/main/samples/FBASample/fba_sample.cs -o - | dotnet run -

Video

MewUI.Demo_0.4.1.mp4

Screenshots

Light	Dark

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✨ Highlights

• 📦 NativeAOT + trimming first
• 🪶 Lightweight by design (small EXE, low memory footprint, fast first frame — see benchmark below)
• 🧩 Fluent C# markup (no XAML)

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🪶 Lightweight

• Executable size: NativeAOT + Trim focused (sample win-x64-trimmed is ~ 2.2 MB)
• Sample runtime benchmark (NativeAOT + Trimmed, 50 launches):

Backend	Loaded avg/p95 (ms)	FirstFrame avg/p95 (ms)	WS avg/p95 (MB)	PS avg/p95 (MB)
Direct2D	10 / 11	178 / 190	40.0 / 40.1	54.8 / 55.8
GDI	15 / 21	54 / 67	15.2 / 15.3	4.6 / 4.8

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🚀 Quickstart

• NuGet: https://www.nuget.org/packages/Aprillz.MewUI/

  • Install: dotnet add package Aprillz.MewUI

• Single-file app (VS Code friendly)

  • See: samples/FBASample/fba_calculator.cs

  • Minimal header (without AOT/Trim options):

    #:sdk Microsoft.NET.Sdk
    #:property OutputType=Exe
    #:property TargetFramework=net10.0
    
    #:package Aprillz.MewUI@0.2.0
    
    // ...

• Run: dotnet run your_app.cs

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🧪 C# Markup at a Glance

• Sample source: https://github.com/aprillz/MewUI/blob/main/samples/MewUI.Sample/Program.cs

   var window = new Window()
       .Title("Hello MewUI")
       .Size(520, 360)
       .Padding(12)
       .Content(
           new StackPanel()
               .Spacing(8)
               .Children(
                   new Label()
                       .Text("Hello, Aprillz.MewUI")
                       .FontSize(18)
                       .Bold(),
                   new Button()
                       .Content("Quit")
                       .OnClick(() => Application.Quit())
               )
       );
  
   Application.Run(window);

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🎯 Concept

MewUI is a code-first GUI framework with three priorities:

• NativeAOT + trimming friendliness
• Small footprint, fast startup, low memory usage
• Fluent C# markup for building UI trees (no XAML)
• AOT-friendly binding

Non-goals (by design):

• WPF-style animations, visual effects, or heavy composition pipelines
• A large, “kitchen-sink” control catalog (keep the surface area small and predictable)
• Complex path-based data binding
• Full XAML/WPF compatibility or designer-first workflows

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✂️ NativeAOT / Trim

• The library aims to be trimming-safe by default (explicit code paths, no reflection-based binding).
• Windows interop uses source-generated P/Invoke (LibraryImport) for NativeAOT compatibility.
• On Linux, building with NativeAOT requires the AOT workload in addition to the regular .NET SDK (e.g. install dotnet-sdk-aot-10.0).
• If you introduce new interop or dynamic features, verify with the trimmed publish profile above.

To check output size locally:

• Publish: dotnet publish .\samples\MewUI.Sample\MewUI.Sample.csproj -c Release -p:PublishProfile=win-x64-trimmed
• Inspect: .artifacts\publish\MewUI.Sample\win-x64-trimmed\

Reference (sample, win-x64-trimmed):

• Aprillz.MewUI.Sample.exe ~ 2,257 KB

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🔗 State & Binding (AOT-friendly)

Bindings are explicit and delegate-based (no reflection):

using Aprillz.MewUI.Binding;
using Aprillz.MewUI.Controls;

var percent = new ObservableValue<double>(
    initialValue: 0.25,
    coerce: v => Math.Clamp(v, 0, 1));

var slider = new Slider().BindValue(percent);
var label  = new Label().BindText(percent, v => $"Percent ({v:P0})");

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🧱 Controls / Panels

Controls (implemented):

• Button
• Label, Image
• TextBox, MultiLineTextBox
• CheckBox, RadioButton
• ComboBox, ListBox
• Slider, ProgressBar
• TabControl, GroupBox
• MenuBar, ContextMenu, ToolTip (in-window popups)
• Window
• DispatcherTimer

Panels:

• Grid (rows/columns with Auto, *, pixel)
• StackPanel (horizontal/vertical + spacing)
• DockPanel (dock edges + last-child fill)
• UniformGrid (equal cells)
• WrapPanel (wrap + item size + spacing)

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🎨 Theme

Theme is split into two parts:

• Palette - colors (including derived colors based on background + accent)
• Theme - non-color parameters (corner radius, default font, plus a Palette)

Accent switching:

Theme.Current = Theme.Current.WithAccent(Color.FromRgb(214, 176, 82));

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🖌️ Rendering Backends

Rendering is abstracted through:

• IGraphicsFactory / IGraphicsContext

Backends:

• Direct2D (Windows)
• GDI (Windows)
• OpenGL (Windows / Linux)

The sample defaults to Direct2D on Windows, and OpenGL on Linux.

• Direct2D: slower startup and larger resident memory, but better suited for complex layouts/effects
• GDI: lightweight and fast startup, but CPU-heavy and not ideal for high-DPI, large windows, or complex UIs
• OpenGL: cross-platform and works with the Linux/X11 host, but currently more limited and still experimental

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🪟 Platform Abstraction

Windowing and the message loop are abstracted behind a platform layer.

Currently implemented:

• Windows (Win32PlatformHost)
• Linux/X11 (experimental)

Linux dialogs dependency

On Linux, MessageBox and file dialogs are currently implemented via external tools:

• zenity (GNOME/GTK)
• kdialog (KDE)

If neither is available in PATH, MewUI throws: PlatformNotSupportedException: No supported Linux dialog tool found (zenity/kdialog).

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📄Docs

• C# Markup
• Binding

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🧭 Roadmap (TODO)

Controls

• ToggleSwitch
• GridView

Features

• Simple template support (Delegate-based)

Platforms

• Linux/Wayland
• macOS

Tooling

• Hot Reload
• Design-time preview