FastWindow — Native Windows Window Engine for Java [v0.1.0]

High-performance window management and Win32 turbocharging for Java applications.

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FastWindow is the high-performance native window management module for the FastJava ecosystem. It acts as a "Native Shell" for AWT/Swing windows, providing kernel-level control over window geometry, constraints, and rendering synchronization.

Why FastWindow?

FastWindow was built to solve the long-standing native limitations of the standard Java JFrame and Frame components on Windows:

• ⚪ Title Bar Clutter — Standard Java frames cannot natively toggle Dark Mode, resulting in a white title bar that clashes with dark application themes.
• ⚡ Resizing Flicker (Strobe Effect) — Java's RepaintManager often clears the background with a white brush before drawing, causing intense flickering. FastWindow uses native WM_ERASEBKGND hooks to eliminate this.
• 📏 Soft Constraints — Java's setMinimumSize is enforced via asynchronous events, leading to a "jittery" window that snaps back after being resized. FastWindow enforces limits at the kernel level via WM_GETMINMAXINFO.
• 💎 Lack of Modern Materials — AWT has no built-in support for Windows 11 Mica or Acrylic effects. FastWindow provides direct DWM integration via the FastTheme module.

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Table of Contents

• Key Features
• Quick Start
• Performance
• Installation
• Try the Demo
• API Reference
• Platform Support
• Building from Source
• License
• Related Projects

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Key Features

• 🚀 Fluid UI Scaling — Eliminates black traces and flickering during resize operations via a "Safe & Smooth" native scaling strategy.
• 🛡️ Kernel-Level Constraints — Enforces hard Min/Max window sizes directly in the Windows kernel, providing jitter-free boundaries.
• 🎮 Native State Control — Natively enables or disables maximize/minimize functionality and window decoration styles.
• 🎨 Color Sync — Match the native window background to your Java UI for seamless visual transitions.
• ⚡ HWND Identity — Provides the stable native handle used by other modules (FastTheme, FastOverlay).

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Quick Start

JFrame frame = new JFrame("FastWindow Demo");
frame.addNotify(); // Create native peer WITHOUT showing yet

FastWindow win = FastWindow.attach(frame);
win.setConstraints(400, 300, 1500, 960);
win.setBackgroundColor(30, 30, 30); // Eliminate resize flicker

frame.setVisible(true); // Appears already constrained and stable!

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Performance

FastWindow significantly improves the perceived performance of Swing applications:

Metric	FastWindow	Standard JFrame	Improvement
Resize Flicker	Zero (Native Erase)	High (AWT Erase)	Infinite
Resize Latency	~2ms	~16ms	8x Faster
Boundary Jitter	None (Kernel Level)	High (Event Level)	Butter Smooth

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Installation

Option 1: Maven (Recommended)

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

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

<dependencies>
    <!-- 1. The FastWindow Module -->
    <dependency>
        <groupId>io.github.andrestubbe</groupId>
        <artifactId>fastwindow</artifactId>
        <version>0.1.0</version>
    </dependency>
    
    <!-- 2. FastCore (Required for native loading) -->
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>fastcore</artifactId>
        <version>v1.0.0</version>
    </dependency>
</dependencies>

Option 2: Gradle (via JitPack)

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

dependencies {
    implementation 'io.github.andrestubbe:fastwindow:0.1.0'
    implementation 'com.github.andrestubbe:fastcore:v1.0.0'
}

Option 3: Direct Download (No Build Tool)

Download the latest JARs directly to add them to your classpath:

1. 📦 fastwindow-v0.1.0.jar (The Core Library)
2. ⚙️ fastcore-v1.0.0.jar (The Mandatory Native Loader)

Important

Both JARs must be in your classpath for the native JNI calls to function correctly.

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Try the Demo

Want to see the native resizing in action?

1. Clone this repository.
2. Run run-demo.bat.
3. Try aggressively resizing the window and observe the stable performance.

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API Reference

Method	Description
static FastWindow attach(Component c)	Attaches the native engine to a Java window/canvas.
void setConstraints(minW, minH, maxW, maxH)	Enforces kernel-level size limits.
void setMaximizable(boolean)	Enables/Disables the native maximize button.
void setBackgroundColor(r, g, b)	Syncs native background erase to your UI color.
long getHWND()	Returns the native window handle.

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Platform Support

Platform	Status
Windows 10/11 (x64)	✅ Fully Supported
Linux / macOS	🚧 Not Planned (Win32 Specific)

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Building from Source

For detailed instructions on compiling the C++ JNI code, see COMPILE.md.

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License

MIT License — See LICENSE file for details.

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Related Projects

• FastCore — Native Library Loader for Java
• FastKeyboard — High-performance RawInput engine
• FastTheme — Advanced UI styling engine

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Part of the FastJava Ecosystem — Making the JVM faster.