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Ole-Morten Duesund f3baa723be Implement two-pass separable Gaussian blur for camera preview 
Replace the single-pass 9-tap directional blur with a three-pass
pipeline: passthrough (camera→FBO), horizontal blur (FBO-A→FBO-B),
vertical blur (FBO-B→screen). This produces a true 2D Gaussian with
a 13-tap kernel per pass, eliminating the visible banding/streaking
of the old approach.

Key changes:
- TiltShiftRenderer: FBO ping-pong with two color textures, separate
  fullscreen quad for blur passes (no crop-to-fill), drawQuad helper
- TiltShiftShader: manages two programs (passthrough + blur), blur
  program uses raw screen-space angle (no camera rotation adjustment)
- tiltshift_fragment.glsl: rewritten for sampler2D in screen space,
  aspect correction on X axis (height-normalized), uBlurDirection
  uniform for H/V selection, wider falloff (3x multiplier)
- New tiltshift_passthrough_fragment.glsl for camera→FBO copy
- TiltShiftOverlay: shrink PINCH_SIZE zone (1.3x, was 2.0x) so
  pinch-to-zoom is reachable over more of the screen
- CameraManager: optimistic zoom update fixes pinch-to-zoom stalling
  (stale zoomRatio base prevented delta accumulation)

Bump version to 1.1.3.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-18 17:38:50 +01:00
app Implement two-pass separable Gaussian blur for camera preview 2026-03-18 17:38:50 +01:00
gradle Add unit tests for BlurParameters and LensController 2026-03-18 16:48:21 +01:00
.gitignore Harden build and config security 2026-03-05 11:55:24 +01:00
build.gradle.kts Initial implementation of Tilt-Shift Camera Android app 2026-01-28 15:26:41 +01:00
bump-version.sh Add version management with auto-bump script 2026-03-05 13:58:22 +01:00
CLAUDE.md Replace Accompanist Permissions with first-party activity-compose API 2026-03-18 16:43:56 +01:00
gradle.properties Initial implementation of Tilt-Shift Camera Android app 2026-01-28 15:26:41 +01:00
gradlew Initial implementation of Tilt-Shift Camera Android app 2026-01-28 15:26:41 +01:00
gradlew.bat Initial implementation of Tilt-Shift Camera Android app 2026-01-28 15:26:41 +01:00
LICENSE Add MIT license 2026-03-05 13:50:37 +01:00
README.md Remove dead code 2026-02-27 15:24:17 +01:00
settings.gradle.kts Initial implementation of Tilt-Shift Camera Android app 2026-01-28 15:26:41 +01:00
tiltshift-spec.md Add radial mode, UI controls, front camera, update to API 35 2026-01-29 11:13:31 +01:00
version.properties Implement two-pass separable Gaussian blur for camera preview 2026-03-18 17:38:50 +01:00

README.md

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 15 (API 35) 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:

./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 & EXIF 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