Delilah - AI Image Generation & Virtual Try-On App

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📱 Screenshots

Login Screen	Home Screen	Gallery View

Image Generation	Virtual Try-On	Virtual Try-On Output

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Overview

Delilah is a production-ready Flutter mobile application that provides AI-powered image generation and editing capabilities. The app connects to a FastAPI backend with Vertex AI for image processing and uses Cloudinary for image storage.

Features

Feature	Endpoint	Description
Image Generation	/api/generate	Generate stunning images from text prompts using Vertex AI Imagen
Virtual Try-On	/api/tryon	Try on clothes virtually by combining person photos with clothing items
Image Editing	/api/edit	Apply filters and semantic modifications to existing images
Image Upscale	/api/upscale	Enhance resolution and remove digital noise from images
Product Makeover	/api/product-makeover	Place products in contextual synthetic backgrounds
Fix Old Image	/api/fixoldimage	Restore old/damaged photos by removing artifacts
Gallery	/api/gallery	View, save, and manage all generated images
Wallpaper	-	Set any image as device wallpaper

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Architecture

Technology Stack

• Frontend: Flutter 3.11+ with Dart
• State Management: Riverpod 2.5+
• Routing: GoRouter 14+
• HTTP Client: Dio
• Image Storage: Cloudinary (unsigned uploads)
• Secure Storage: flutter_secure_storage (JWT tokens)
• Image Saving: Gal (gallery access)
• Image Picking: image_picker

Project Structure

lib/
├── main.dart                    # App entry point
├── core/
│   ├── config.dart              # API URLs and Cloudinary config
│   ├── router.dart              # GoRouter configuration with navigation
│   ├── network/
│   │   └── pb_interceptor.dart   # HTTP interceptors
│   ├── services/
│   │   ├── cloudinary_service.dart   # Cloudinary upload with caching
│   │   └── secure_storage.dart       # Token persistence
│   └── theme/
│       ├── theme_controller.dart     # Design tokens (colors, spacing)
│       └── glass_theme.dart          # Theme configuration
├── features/
│   ├── auth/                    # Authentication
│   │   ├── data/
│   │   │   └── auth_repository.dart  # Login/register API calls
│   │   ├── presentation/
│   │   │   ├── login_screen.dart
│   │   │   └── register_screen.dart
│   │   └── providers/
│   │       └── auth_provider.dart    # Auth state management
│   ├── home/
│   │   └── presentation/
│   │       └── home_screen.dart      # Hero section + quick actions
│   ├── endpoints/
│   │   ├── image_generation/   # Generate images from prompts
│   │   ├── virtual_tryon/       # Virtual clothing try-on
│   │   ├── image_edit/         # Image editing & filters
│   │   ├── upscale/            # Image upscaling
│   │   ├── product_makeover/   # Product background change
│   │   └── fix_old_image/      # Photo restoration
│   └── history/
│       ├── presentation/
│       │   └── history_screen.dart  # Gallery with save/wallpaper
│       └── providers/
│           └── history_provider.dart # Gallery API state
└── shared/
    ├── widgets/
    │   ├── glass_button.dart   # Custom styled button
    │   ├── glass_input.dart    # Custom styled input
    │   └── async_value_widget.dart
    └── utils/
        └── wallpaper_engine.dart    # Android wallpaper setter

State Management Pattern

The app uses Riverpod with a consistent pattern across all features:

1. Provider: Defines the state class (immutable data class)
2. Notifier: Handles state mutations and async operations
3. Repository: Makes API calls with proper auth headers
4. Screen: Consumes state via ref.watch() and triggers actions via ref.read()

Example pattern:

// State class
class TryOnState {
  final File? personImage;
  final String? resultUrl;
  final bool isGenerating;
  // ...
}

// Notifier
class TryOnNotifier extends Notifier<TryOnState> {
  Future<void> generate() async {
    state = state.copyWith(isGenerating: true);
    // API call...
    state = state.copyWith(resultUrl: result, isGenerating: false);
  }
}

// Provider
final tryOnNotifierProvider = NotifierProvider<TryOnNotifier, TryOnState>(() => TryOnNotifier());

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Backend API

Authentication

The app uses JWT tokens from PocketBase for authentication.

Login: POST /api/auth/login

{"email": "user@example.com", "password": "password"}

Response:

{"token": "jwt_token_here"}

Image Endpoints

All endpoints (except login/register) require Authorization: Bearer <token> header.

Method	Endpoint	Request Body	Response
POST	/api/generate	{"prompt": "..."}	{"status": "success", "secure_url": "..."}
POST	/api/tryon	{"person_image_url": "...", "product_image_url": "..."}	{"status": "success", "secure_url": "..."}
POST	/api/edit	{"image_url": "...", "edit_prompt": "..."}	{"status": "success", "secure_url": "..."}
POST	/api/upscale	{"image_url": "...", "enhancement_focus": "..."}	{"status": "success", "secure_url": "..."}
POST	/api/product-makeover	{"product_image_url": "...", "background_context": "..."}	{"status": "success", "secure_url": "..."}
POST	/api/fixoldimage	{"image_url": "...", "repair_instructions": "..."}	{"status": "success", "secure_url": "..."}
GET	/api/gallery	-	{"images": [{"secure_url": "...", "public_id": "...", ...}]}
DELETE	/api/gallery	{"public_id": "..."}	{"success": true}

Cloudinary Integration

Images are uploaded to Cloudinary with folder structure:

delilah_users/<email_cleaned>/<tag>/

Example: delilah_users/user_example_com/generated_studio/

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Design System

Colors

Color	Hex	Usage
canvasWhite	#FFFFFF	Main background
cohereBlack	#1A1A1A	Primary text
actionBlue	#4F46E5	Primary actions
softStone	#F3F4F6	Card backgrounds
hairline	#E5E7EB	Borders
mutedSlate	#6B7280	Secondary text
deepEnterpriseGreen	#10B981	Success states
errorRed	#EF4444	Error states

Typography

Uses Unica77 font family (via design tokens in theme_controller.dart):

• headlineLarge: 28px, bold
• titleMedium: 18px, semibold
• bodyMedium: 14px, regular
• bodySmall: 12px, regular

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Navigation

The app uses a Shell Route pattern with bottom navigation:

Home (default landing)
  └── Quick actions → Generate, Try-On, Edit, Gallery
  
Tools (modal menu)
  ├── Generate Image
  ├── Virtual Try-On
  ├── Edit Image
  ├── Upscale
  ├── Product Makeover
  └── Fix Old Image
  
Gallery
  └── Grid view → Detail sheet → Save/Wallpaper/Delete
  
Logout → Login screen

Navigation Logic

• Unauthenticated users are redirected to /login
• Authenticated users on auth pages are redirected to /home
• Back gesture from any tool goes to Home (not exit app)
• Gallery auto-refreshes on first load only

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Building & Running

Prerequisites

• Flutter 3.11+
• Dart 3.11+
• Android SDK with API 21+

Development

# Get dependencies
flutter pub get

# Run on connected device/emulator
flutter run

# Analyze code
flutter analyze

# Build debug APK
flutter build apk --debug

# Build release APK
flutter build apk --release

signature key

android/key.properties

storePassword=
keyPassword=
keyAlias=upload
storeFile=../../keystore/release-key.jks

Release Build

The release build uses a custom keystore located at ../keystore/release-key.jks.

# Build release (signs with release key)
flutter build apk --release

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Permissions

Android (AndroidManifest.xml)

• INTERNET - API calls
• SET_WALLPAPER - Set wallpaper feature
• READ_EXTERNAL_STORAGE (API ≤ 32) - Gallery access
• WRITE_EXTERNAL_STORAGE (API ≤ 29) - Save to gallery

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Key Implementation Details

Cloudinary Upload with Caching

Images uploaded from device are cached by file path to avoid re-uploading the same image:

final cachedUrl = cloudinary.getCachedUrl(file.path);
if (cachedUrl != null) {
  state = state.copyWith(imageUrl: cachedUrl);
  return;
}

Save to Gallery

Uses gal package for modern gallery access:

final tempDir = await getTemporaryDirectory();
final tempFile = File('${tempDir.path}/image.jpg');
await tempFile.writeAsBytes(response.bodyBytes);
await Gal.putImage(tempFile.path);
await tempFile.delete();

Wallpaper Setting (Android)

Uses platform channel to set wallpaper with center-crop for proper aspect ratio:

// android/app/src/main/kotlin/.../MainActivity.kt
val wallpaperManager = WallpaperManager.getInstance(applicationContext)
wallpaperManager.setBitmap(bitmap, null, true, WallpaperManager.FLAG_SYSTEM)

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Version History

Version	Changes
1.0.8	Added launcher icons, assets folder
1.0.6	Fixed save image permission error
1.0.5	Add save/fullscreen to new endpoints, back gesture fix, gallery auto-refresh
1.0.4	Fix layout overflow in home screen modal
1.0.3	Add local image picker + Cloudinary upload, create homepage
1.0.2	Add missing API endpoints (edit, upscale, product-makeover, fixoldimage)
1.0.1	Add gallery delete functionality
1.0.0	Initial release with auth, generate, tryon, gallery

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License

MIT License

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Contributing

1. Fork the repository
2. Create a feature branch
3. Make changes and test
4. Run flutter analyze to check for issues
5. Commit with clear description
6. Push and create pull request