# Tilt-Shift Camera

A dedicated Android camera app for tilt-shift photography with real-time preview, touch-based controls, and proper EXIF handling.

## Features

- **Real-time tilt-shift effect preview** - See the blur effect as you compose your shot
- **Touch-based controls**:
  - Single finger drag to move the focus line position
  - Two-finger rotation to adjust blur angle
  - Pinch gesture to adjust blur zone size
  - Pinch in center to zoom camera
- **Zoom controls** - Quick presets (0.5x, 1x, 2x, 5x) plus pinch-to-zoom
- **Auto picture orientation detection** - Photos saved with correct EXIF orientation
- **GPS location tagging** - Optional EXIF GPS data from device location
- **Haptic feedback** - Tactile response for all interactions
- **Saves to gallery** - Photos saved to Pictures/TiltShift/ folder

## Requirements

- Android 8.0 (API 26) or higher
- Device with camera
- OpenGL ES 2.0 support

## Building

1. Open the project in Android Studio
2. Sync Gradle files
3. Build and run on a physical device (camera preview won't work on emulator)

Or from command line:
```bash
./gradlew assembleDebug
```

## Permissions

- **Camera** (required) - For capturing photos
- **Location** (optional) - For GPS tagging in EXIF data
- **Vibrate** - For haptic feedback

## Architecture

The app uses:
- **CameraX** - Jetpack camera library for camera preview and capture
- **OpenGL ES 2.0** - Real-time shader-based blur effect
- **Jetpack Compose** - Modern declarative UI
- **Kotlin Coroutines & Flow** - Asynchronous operations and state management

### Project Structure

```
app/src/main/java/no/naiv/tiltshift/
├── MainActivity.kt           # Entry point with permission handling
├── camera/
│   ├── CameraManager.kt      # CameraX setup and control
│   ├── LensController.kt     # Lens/zoom switching
│   └── ImageCaptureHandler.kt # Photo capture with effect
├── effect/
│   ├── TiltShiftRenderer.kt  # OpenGL renderer
│   ├── TiltShiftShader.kt    # GLSL shader management
│   └── BlurParameters.kt     # Effect state
├── ui/
│   ├── CameraScreen.kt       # Main Compose screen
│   ├── TiltShiftOverlay.kt   # Touch gesture handling & visualization
│   ├── ZoomControl.kt        # Zoom UI component
│   └── LensSwitcher.kt       # Lens selection UI
├── storage/
│   ├── PhotoSaver.kt         # MediaStore integration
│   └── ExifWriter.kt         # EXIF metadata handling
└── util/
    ├── OrientationDetector.kt
    ├── LocationProvider.kt
    └── HapticFeedback.kt
```

## How the Tilt-Shift Effect Works

The tilt-shift effect simulates a selective focus lens that makes scenes appear miniature. The app achieves this through:

1. **Camera Preview** → OpenGL SurfaceTexture
2. **Fragment Shader** calculates distance from the focus line for each pixel
3. **Gradient blur** is applied based on distance - center stays sharp, edges blur
4. **Two-pass Gaussian blur** (optimized as separable passes) for quality and performance

## License

MIT