Files
ledgrab/server
alexei.dolgolyov 31c6c3abb2 feat(devices): Open Pixel Control (OPC) target type
Adds support for Open Pixel Control receivers (Fadecandy boards,
xLights/Falcon endpoints, OPC bridges, art-installation controllers,
hobbyist LED driver software). OPC is a tiny TCP protocol on port
7890 with a 4-byte header [channel][cmd][len_hi][len_lo] + RGB body.

Backend:
- OPCClient opens one persistent TCP connection and streams frames as
  header+body byte pairs. Channel 0 broadcasts to every output on the
  OPC server; channels 1-255 address a specific channel on multi-output
  servers (Fadecandy with multiple Open Pixel chains).
- supports_fast_send=True with a synchronous send_pixels_fast hot path.
  The fast path skips the async drain so the OS write-buffer flushes
  on its own schedule -- exactly what ambilight streaming wants.
- Brightness applies client-side before the frame is sent (OPC has no
  reply channel for hardware-side brightness).
- Health check opens a TCP connection and closes it.
- OPCConfig joins the typed config union; storage gains an opc_channel
  field; full to_dict/from_dict/to_config wiring.
- 36 unit tests cover URL parsing, header construction, send_pixels
  emitting header+body in order, brightness application, list and
  flat-array input shapes, drain behavior, connection lifecycle,
  provider validate/discover/capabilities, Device.to_config round-trip.

Frontend:
- 'opc' in DEVICE_TYPE_KEYS (next to 'ddp'), paper-plane icon -- same
  as DDP since both are open pixel-streaming protocols.
- isOpcDevice predicate + per-type field show/hide.
- Optional channel number input (default 0 = broadcast) with hint copy
  explaining the channel semantics.
- Locale strings in en/ru/zh.

No native discovery (OPC has no discovery protocol); users supply
the receiver IP manually.
2026-05-16 03:02:41 +03:00
..
2026-05-10 23:57:47 +03:00

LedGrab - Server

High-performance FastAPI server that captures screen content and controls WLED devices for ambient lighting.

Overview

The server component provides:

  • 🎯 Real-time Screen Capture - Multi-monitor support with configurable FPS
  • 🎨 Advanced Processing - Border pixel extraction with color correction
  • 🔧 Flexible Calibration - Map screen edges to any LED layout
  • 🌐 REST API - Complete control via 25+ REST endpoints
  • 💾 Persistent Storage - JSON-based device and configuration management
  • 📊 Metrics & Monitoring - Real-time FPS, status, and performance data

Quick Start

# Start server
docker-compose up -d

# View logs
docker-compose logs -f

# Stop server
docker-compose down

Server runs on: http://localhost:8080

Option 2: Python

# Create virtual environment
python -m venv venv

# Activate
source venv/bin/activate  # Linux/Mac
venv\Scripts\activate      # Windows

# Install dependencies
pip install .

# Set PYTHONPATH
export PYTHONPATH=$(pwd)/src  # Linux/Mac
set PYTHONPATH=%CD%\src       # Windows

# Run server
uvicorn ledgrab.main:app --host 0.0.0.0 --port 8080

Installation

Requirements

  • Python 3.11+ (for Python installation)
  • Docker & Docker Compose (for Docker installation)
  • WLED device on your network

See ../INSTALLATION.md for comprehensive installation guide.

Configuration

Configuration File

Edit config/default_config.yaml:

server:
  host: "0.0.0.0"
  port: 8080
  log_level: "INFO"

processing:
  default_fps: 30        # Target frames per second
  max_fps: 60           # Maximum allowed FPS
  border_width: 10      # Pixels to sample from edge

wled:
  timeout: 5            # Connection timeout (seconds)
  retry_attempts: 3     # Number of retries

storage:
  devices_file: "data/devices.json"

logging:
  format: "json"
  file: "logs/ledgrab.log"

Environment Variables

# Server configuration
export LEDGRAB_SERVER__HOST="0.0.0.0"
export LEDGRAB_SERVER__PORT=8080
export LEDGRAB_SERVER__LOG_LEVEL="INFO"

# Processing configuration
export LEDGRAB_PROCESSING__DEFAULT_FPS=30
export LEDGRAB_PROCESSING__BORDER_WIDTH=10

# WLED configuration
export WLED_WLED__TIMEOUT=5

Usage

WLED Device Setup

Important: Configure your WLED device using the official WLED web interface before connecting it to this controller:

  1. Access WLED Interface: Open http://[wled-ip] in your browser
  2. Configure Device Settings:
    • Set LED count and type
    • Configure brightness, color order, and power limits
    • Set up segments if needed
    • Configure effects and presets

This controller only sends pixel color data - it does not manage WLED settings like brightness, effects, or segments. All WLED device configuration should be done through the official WLED interface.

API Documentation

Quick Example

# 1. Add device
curl -X POST http://localhost:8080/api/v1/devices \
  -H "Content-Type: application/json" \
  -d '{"name":"Living Room","url":"http://192.168.1.100","led_count":150}'

# 2. Start processing
curl -X POST http://localhost:8080/api/v1/devices/{device_id}/start

# 3. Check status
curl http://localhost:8080/api/v1/devices/{device_id}/state

Testing

# Run all tests
pytest

# Run with coverage
pytest --cov=ledgrab --cov-report=html

# Run specific test
pytest tests/test_screen_capture.py -v

Development

Project Structure

src/ledgrab/
├── main.py              # FastAPI application
├── config.py            # Configuration
├── api/                 # API routes
├── core/                # Core functionality
│   ├── screen_capture.py
│   ├── wled_client.py
│   ├── calibration.py
│   └── processor_manager.py
├── storage/             # Data persistence
└── utils/               # Utilities

Code Quality

# Format code
black src/ tests/

# Lint code
ruff check src/ tests/

License

MIT - see ../LICENSE

Support