FastUI — High-Performance, Deterministic UI for Java [v0.1.0]

A retained-mode UI framework for the FastJava ecosystem, focusing on per-component baked layers, zero-allocation rendering, and hardware-locked performance.

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FastUI is a next-generation UI framework built from the ground up for maximum speed and zero-copy efficiency. Unlike traditional Java UI frameworks (Swing/AWT) that rasterize vector graphics on every frame, FastUI uses a Retained-Mode Baking Pipeline to achieve multi-thousand FPS performance on modern hardware.

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Table of Contents

• Key Features
• Why FastUI?
• Quick Start
• Performance
• Installation
• Try the Demo
• API Reference
• Platform Support
• License
• Related Projects

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Key Features

• 🚀 Baked Layers — Components render once into BufferedImage caches.
• ⚡ Zero Allocation — No objects are created during the rendering of a frame.
• 🎨 DPI-Aware — Integrated with FastDisplay for pixel-perfect scaling.
• 🧱 Pure Java Core — A lightweight, decoupled codebase with no mandatory native dependencies.
• 🔧 Deterministisch — Predictable performance and hardware-locked timing.

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Why FastUI?

Standard Java UI frameworks (AWT/Swing) were designed in an era of static interfaces and slow refresh rates. In today's world of high-DPI displays, 144Hz+ monitors, and AI-driven automation, the "Immediate-Mode" rasterization model has become a bottleneck.

FastUI was built to bridge this gap by treating UI components as Persistent Graphical Assets. By shifting the workload from CPU-heavy rasterization to GPU-friendly memory blitting, we unlock a level of fluidity previously unreachable in the JVM.

Eliminating Framework Bottlenecks

• 🔴 High Rasterization Overhead — Rasterizing shapes and text every frame is CPU intensive. FastUI bakes components into offscreen buffers.
• 📉 Garbage Collector Pressure — Traditional loops allocate thousands of objects. FastUI's render path is allocation-free.
• 🌊 Resizing Flicker — Standard resizing is jittery. FastUI integrates with FastWindow for butter-smooth window scaling.
• ⏱️ Lack of VSync Alignment — FastUI is natively synchronized to the display refresh rate via FastDWM.

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Quick Start

// Initialize the UI Root
FastContainer root = new FastContainer();

// Add a High-Performance Button
FastButton btn = new FastButton("Initialize Engine");
btn.setBounds(50, 50, 200, 50);
root.add(btn);

// In your VSync-locked render loop (e.g. using FastDWM)
root.render(g2d); 

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Performance

FastUI is designed to saturate high-refresh-rate monitors (144Hz+) with minimal CPU footprint.

Metric	FastUI	Standard Swing	Improvement
Render Time (100 Buttons)	< 0.1 ms	~4.5 ms	45x Faster
Memory Allocations	0 per frame	~120 KB per frame	Infinite
Jitter during Resize	Zero (Sync'd)	High	Liquid Smooth

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Installation

Option 1: Maven (Recommended)

Add the JitPack repository and the dependency to your pom.xml:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>io.github.andrestubbe</groupId>
        <artifactId>fastui</artifactId>
        <version>v0.1.0</version>
    </dependency>
</dependencies>

Option 2: Gradle

Add the JitPack repository to your build.gradle:

repositories {
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'io.github.andrestubbe:fastui:v0.1.0'
}

Option 3: Direct Download (No Build Tool)

For simple projects, you can download the standalone JAR directly:

1. 📦 fastui-v0.1.0.jar (The Core Library)

Note

Since FastUI core is pure Java, no additional native loader (FastCore) is strictly required unless you are using the native integration features provided in the examples.

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Try the Demo

1. Clone this repository.
2. Run the provided batch file from the root:

.\run-demo.bat

Note: The demo is located in the examples/ directory and demonstrates the library's integration with FastWindow and FastTheme.

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API Reference

Component	Description
FastComponent	Base class for all widgets with baking logic.
FastContainer	Logical grouping for absolute-positioned children.
FastButton	Reference widget with Normal, Hover, and Pressed states.
FastShapeFactory	DPI-aware shape generator for borders and backgrounds.

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Platform Support

FastUI is a pure Java library and is natively compatible with any platform supporting Java 17+.

Platform	Status
Windows 10/11	✅ Fully Supported
Linux	✅ Fully Supported
macOS	✅ Fully Supported

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License

MIT License — See LICENSE file for details.

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Related Projects

• FastCore — Native Library Loader for Java
• FastWindow — Native Window Engine
• FastDisplay — Real-time DPI monitoring
• FastTheme — Advanced UI styling engine

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Part of the FastJava Ecosystem — Making the JVM faster.