Floating Ghost Image

A lightweight Android overlay app that displays a semi-transparent reference image on top of other apps. Perfect for drawing, tracing, comparing images, or any task requiring a visual reference overlay.

Features

• Floating Overlay: Display any image as a semi-transparent overlay on top of other apps
• Adjustable Opacity: Control transparency from 0% to 100%
• Lock Mode: Enable passthrough to interact with apps below the overlay
• Edit Mode: Drag, zoom, rotate, and position the image
• Share Integration: Start overlay directly from any app's share menu
• Minimal Size: Optimized APK under 2MB
• Clean UI: Only used XML/Kotlin

Requirements

• Android 7.0 (API 24) or higher
• Overlay permission (requested on first use)

Installation

1. Download the APK from Releases
2. Install the APK on your device
3. Grant overlay permission when prompted

Usage

Starting the Overlay

1. Open Floating Ghost Image
2. Tap the image preview area to select an image
3. Tap the START button
4. Grant overlay permission if prompted
5. The app minimizes and shows a small floating icon
6. Tap the icon to show/hide the image

Editing the Overlay

1. Long press the floating icon to open controls
2. Drag the icon to reposition it
3. Use the opacity slider to adjust transparency
4. Toggle the lock switch:
   • ON (locked): Image is passthrough - touches go through to apps below
   • OFF (unlocked): You can drag, zoom, and rotate the image
5. Tap the back button to return to icon-only mode
6. Tap the close button to stop the overlay

Using with Image Sharing

1. Open any app with an image (Gallery, Browser, etc.)
2. Tap the Share button
3. Select Floating Ghost Image from the share menu
4. The overlay starts automatically with your image

Controls

• Floating Icon: Tap to show/hide image, long press to edit, drag to move
• Opacity Slider: Adjust image transparency (0-100%)
• Lock Switch: Enable/disable passthrough mode
• Back Button: Return to icon-only mode
• Close Button: Stop the overlay completely

Optimization Features

This app has been heavily optimized for minimal APK size:

• ProGuard/R8 code shrinking and obfuscation
• Resource shrinking (removes unused resources)
• Removed xxxhdpi and xxhdpi icon densities
• Vector drawables only (no PNG assets)
• Minimal dependencies (only essential AndroidX libraries)
• Aggressive ProGuard rules (removes debug logging)
• Native library compression disabled (extractNativeLibs=false)
• Build features optimization (disabled unused features)

Technical Details

• Minimum SDK: 24 (Android 7.0)
• Target SDK: 36 (Android 15)
• Language: Kotlin
• Architecture: Single activity + foreground service
• Permissions: SYSTEM_ALERT_WINDOW (overlay permission)

Project Structure

app/
├── src/main/
│   ├── java/com/rvoidex7/floatingghostimage/
│   │   ├── MainActivity.kt          # Main UI screen
│   │   └── FloatingImageService.kt  # Overlay service
│   ├── res/
│   │   ├── drawable/                # Vector drawables
│   │   ├── layout/                  # XML layouts (2 files)
│   │   ├── mipmap-*/                # App icons (mdpi to xhdpi)
│   │   └── values/                  # Colors, strings, themes
│   └── AndroidManifest.xml
├── build.gradle.kts                 # App-level build config
└── proguard-rules.pro               # ProGuard optimization rules

Building from Source

Prerequisites

• Android Studio Arctic Fox or newer
• JDK 11 or higher
• Android SDK with API 36

Setup

1. Clone the repository:

git clone https://github.com/rvoidex7/floating-ghost-image.git
cd floating-ghost-image

2. Create gradle.properties file:

# Copy the example file
cp gradle.properties.example gradle.properties

The example file contains all necessary Gradle settings. Release signing configuration is only needed by the maintainer - contributors can skip those lines and use debug builds.

Build Steps

# Build debug APK
./gradlew assembleDebug

# Install to connected device
./gradlew installDebug

# Run on connected device
./gradlew installDebug
adb shell am start -n com.rvoidex7.floatingghostimage/.MainActivity

The debug APK will be located at app/build/outputs/apk/debug/app-debug.apk

Note: Release builds are signed by the maintainer. Contributors should use debug builds for development and testing.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is open source and available under the MIT License.

Changelog

Version 1.0 (Current)

• Initial release
• Basic overlay functionality
• Lock/Edit mode toggle
• Image sharing support
• Size optimizations (APK under 2MB)

Support

• GitHub Issues: Report a bug
• GitHub Discussions: Ask questions

Credits

Developed by @rvoidex7

Privacy

This app:

• Does NOT collect any user data
• Does NOT require internet permission
• Does NOT use analytics or tracking
• Only accesses images you explicitly select
• Stores no data outside of temporary image URIs

All processing happens locally on your device.