https://github.com/davehorner/e_grid#readme

e_grid: Advanced Window Grid Management System

A comprehensive, event-driven window management system that provides real-time window tracking, grid-based positioning, and efficient IPC-based communication across multiple monitors.

7/25 - now exposes e_grid_all which will grid all windows except the initial focused window. All other windows are placed across all monitors in an "optimal" way. If you open or close a window, the monitor grids will grow or shrink to accommodate; the windows will animate to their target cells with a random ease type.

---

NOTICE: This repository is in an interesting state; the examples and functionality may or may not be implemented. Have a look at e_midi which includes an example of playing a midi sound using the focus and defocused events. Aside from that; Feel free to take a look at the LLM cruft, it will give you an idea of some of the directions this project could go.

Dave Horner 6/25 MIT/Apache License

Architecture Overview

┌─────────────────────┐    WinEvents     ┌──────────────────────┐
│   Windows System    │ ──────────────→  │   IPC Server Demo    │
│ - Window Creation   │                  │  - Minimal callbacks │
│ - Window Movement   │                  │  - Main loop logic   │
│ - Focus Changes     │                  │  - Window rescanning │
│ - Window Destroy    │                  │  - IPC publishing    │
└─────────────────────┘                  │  - Focus tracking    │
                                         └──────────┬───────────┘
                                                    │ iceoryx2 IPC
                                                    │ Multi-Service:
                                                    │ • Grid Events
                                                    │ • Window Details  
                                                    │ • Focus Events ⭐
                                                    │ • Commands
                                                    │ • Responses
                                                    ▼
                          ┌─────────────────────────────────────────┐
                          │              Client Applications         │
                          ├─────────────────────┬───────────────────┤
                          │  Grid Client Demo   │  Focus Demo Apps  │
                          │  - Real-time grids  │  - Focus tracking │
                          │  - Window details   │  - Event logging  │
                          │  - Throttled UI     │  - App filtering  │
                          │  - Non-blocking     │  - Multi-client   │
                          └─────────────────────┴───────────────────┘

📊 Grid Display Example

Virtual Grid (All Monitors):
════════════════════════════════════════════════════════════════
    0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 
 0 ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· 
 1 ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· 
 2 ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· 
 3 ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· 
 4 ██ ██ ██ ·· ·· ·· ·· ██ ██ ██ ██ ██ ·· ·· ·· ·· ·· ·· ·· ██ ██ ██ ██ ██ 
 5 ██ ██ ██ ·· ·· ·· ·· ██ ██ ██ ██ ██ ·· ·· ·· ·· ·· ·· ·· ██ ██ ██ ██ ██ 
 6 ██ ██ ██ ·· ·· ·· ·· ██ ██ ██ ██ ██ ·· ·· ·· ·· ·· ·· ·· ██ ██ ██ ██ ██ 
 7 ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· 

Monitor 0 Grid (1920x1080):
══════════════════════════════════════════════════════════
    0  1  2  3  4  5  6  7  8  9 10 11 
 0 ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· 
 1 ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· 
 2 ·· ·· ·· ██ ██ ██ ██ ·· ·· ·· ·· ·· 
 3 ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· 
 4 ██ ██ ██ ·· ·· ·· ·· ██ ██ ██ ██ ██ 
 5 ██ ██ ██ ·· ·· ·· ·· ██ ██ ██ ██ ██ 
 6 ██ ██ ██ ·· ·· ·· ·· ██ ██ ██ ██ ██ 
 7 ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· ·· 

Active Windows:
██ Notepad [HWND: 12345678] (cells: 12)
██ File Explorer [HWND: 87654321] (cells: 20)
██ VS Code [HWND: 11223344] (cells: 16)

🔧 Technical Implementation

Core Technologies

• Rust with winapi for Windows API integration
• iceoryx2 for high-performance IPC communication (64KB buffer sizes)
• crossterm for colored terminal output
• Windows WinEvents for real-time event detection with minimal callbacks

Key Features

• Thread-Safe Design: Uses Arc<Mutex<>> for safe concurrent access
• Deadlock Prevention: Minimal WinEvent processing, heavy work in main loops
• Multi-Monitor Aware: Automatic detection and handling of monitor configurations
• Memory Safe: Leverages Rust's ownership system and explicit safety documentation
• Modular Architecture: Clean separation of concerns between tracking, IPC, and UI
• Smart Grid Detection: Coverage-based algorithm with configurable thresholds for precise cell assignment
• Non-blocking UI: Client uses try_lock and display throttling for responsive interface

Window Management Process

1. WinEvent Registration: Registers for comprehensive window events (CREATE, MOVE, DESTROY, etc.)
2. Minimal Callbacks: WinEvent handlers only log events, preventing deadlocks
3. Main Loop Processing: Server periodically scans windows and updates grid (every 2 seconds)
4. Multi-Monitor Detection: Enumerates all connected monitors and their configurations
5. Coverage-Based Grid Calculation: Calculates intersection areas between windows and grid cells
6. Threshold-Based Assignment: Only assigns cells where window coverage exceeds configurable threshold
7. Incremental Updates: Server publishes only changed window details via IPC
8. Real-Time Synchronization: Client maintains matching grid state through event processing
9. IPC Communication: High-performance message passing through iceoryx2 with large buffers

Safety and Reliability

• Static Safety: Explicit use of raw pointers with comprehensive safety documentation
• Deadlock Prevention: Minimal processing in system callbacks, heavy work in main loops
• Error Handling: Comprehensive error handling throughout the IPC and windowing layers
• Resource Cleanup: Proper cleanup of hooks, handles, and IPC resources
• Thread Safety: All shared state protected by mutexes with non-blocking try_lock patterns
• IPC Reliability: Large buffer sizes (64KB) and error recovery prevent message loss

🎯 NEW: Unified E-Grid Binary

Major Update: E-Grid now provides a single, intelligent e_grid binary that auto-detects your needs!

✨ Smart Auto-Detection:

• No server running? → Starts server + detached client automatically
• Server already running? → Connects as interactive client
• Force specific mode → Use e_grid server or e_grid client

# One command does it all - auto-detects and starts appropriate mode
cargo run --bin e_grid

# Or use the built binary directly
./target/debug/e_grid

🎯 What you get:

• Full server with focus tracking, multi-monitor grids, animations, layouts
• Detached client for real-time grid visualization
• Interactive mode for live grid monitoring
• Smart detection - no manual server/client coordination needed

📖 Jump to Quick Start

---

🎯 NEW: Focus Event Tracking Integration

Major Update: E-Grid now includes comprehensive window focus tracking directly integrated into the main server!

✨ Key Highlights:

• Complete Focus Coverage: Both FOCUSED and DEFOCUSED events in real-time
• Zero Setup: No separate focus server needed - it's built into the main e_grid server
• Production Ready: Full integration with existing grid management features
• Multi-Client Support: Up to 8 applications can subscribe to focus events simultaneously
• Rich Event Data: Process ID, window titles, hash-based identification, precise timestamps

# Quick Test - Focus Events with Main Server
cargo run --bin e_grid                   # Auto-starts server + client
cargo run --example simple_focus_demo    # Terminal 2: Focus tracking client
# Now click between windows to see real-time FOCUSED/DEFOCUSED events!

📖 Jump to Focus Event Documentation

---

🎯 Core Features

Event-Driven Real-Time Window Tracking

• WinEvent Integration: Uses Windows WinEvent hooks for true real-time window detection
• Non-blocking Architecture: Minimal WinEvent callbacks prevent system deadlocks
• Efficient IPC: iceoryx2-based high-performance inter-process communication
• Multi-Monitor Support: Tracks windows across all connected monitors with per-monitor grids
• Visual Grid Display: Shows both virtual (spanning all monitors) and per-monitor 8x12 grids

Advanced Client-Server Architecture

• Dedicated Server: ipc_server_demo - Handles window tracking and event publishing
• Intelligent Client: grid_client_demo - Real-time grid reconstruction and display
• Live Synchronization: Server publishes individual window details for efficient updates
• Command Processing: GetWindowList, GetGridState, window assignment commands
• Background Monitoring: Client receives real-time updates and maintains matching grid state

🎯 NEW: Focus Event Tracking System

• Real-Time Focus Detection: Track window focus/defocus events as they happen
• Complete Event Coverage: Both FOCUSED (gained focus) and DEFOCUSED (lost focus) events
• Rich Event Data: Process ID, window title, app hash, and precise timestamps
• Multi-Client Support: Up to 8 simultaneous focus event subscribers
• Hash-Based Identification: Efficient app and window identification for filtering
• Production Ready: Integrated into main server, no separate focus server needed

Focus Event Types:

• FOCUSED (0): When a window gains focus (user clicks on it)
• DEFOCUSED (1): When a window loses focus (user clicks elsewhere)
• Window Details: Process ID, window title, calculated hashes for identification
• Timing: Microsecond-precision timestamps for event ordering

Smart Window Detection & Assignment

• Coverage-Based Algorithm: Only marks cells as occupied when windows cover ≥30% of cell area
• Dual Assignment Modes:
  • Virtual Grid: Assign windows using coordinates spanning all monitors
  • Monitor-Specific: Assign windows to specific cells on individual monitors
• Precise Grid Representation: Eliminates false positives from boundary overlaps
• Configurable Thresholds: Adjustable coverage percentage for different use cases

Efficient Communication System

• Event Publishing: Server publishes CREATE/MOVE/DESTROY events for individual windows
• On-Demand Data: Client requests full window list only when needed
• Incremental Updates: Server sends only changed window details, not full state
• Deadlock Prevention: Minimal processing in system callbacks
• High Performance: Zero-copy data sharing via iceoryx2

🎯 Smart Grid Detection System

Coverage-Based Cell Assignment

E-Grid uses an intelligent coverage-based algorithm to determine which grid cells are occupied by windows. Instead of simple boundary checking, it calculates the actual intersection area between windows and grid cells.

How It Works

1. Coverage Calculation: For each potential grid cell, the system calculates what percentage of the cell area is covered by the window
2. Threshold Comparison: Only cells with coverage ≥ 30% (configurable) are marked as occupied
3. Precise Assignment: When you assign a window to a single cell, it will only show up in that cell unless it significantly overlaps others

Configuration

// In src/lib.rs - adjustable coverage threshold
const COVERAGE_THRESHOLD: f32 = 0.3; // 30% coverage required

Threshold Options:

• 0.1 (10%) - Very sensitive, small overlaps count as occupation
• 0.3 (30%) - Default, balanced approach for most use cases
• 0.5 (50%) - Window must cover majority of cell to count
• 0.8 (80%) - Very strict, window must nearly fill entire cell

Benefits

• ✅ Accurate Single-Cell Assignment: Windows assigned to one cell show up in only that cell
• ✅ No False Positives: Eliminates boundary-overlap issues
• ✅ Flexible Window Sizes: Works with any window dimensions
• ✅ Consistent Behavior: Predictable grid representation regardless of window positioning

🏗️ Architecture

The system consists of several key components:

1. WindowTracker Core (lib.rs): Main window tracking and grid management
2. Shell Hooks (window_events.rs): Windows API integration for event detection
3. IPC Layer (ipc.rs): iceoryx2-based inter-process communication
4. Interactive Client (ipc_demo.rs): Command-line interface for window control

Grid System

• Virtual Grid: Single unified grid spanning all monitors (coordinates are global)
• Monitor Grids: Individual 8x12 grids for each connected monitor
• Automatic Scaling: Grid coordinates calculated based on monitor resolution and layout
• Coverage-Based Detection: Uses intersection area calculations to determine cell occupancy
• Configurable Threshold: Adjustable coverage percentage (default 30%) for precise grid representation

🚀 Getting Started

Prerequisites

• Windows 10/11
• Rust (latest stable)
• Git

Installation

git clone <repository>
cd e_grid
cargo build --release

Quick Start - Event-Driven System

1. Start the Server (Real-time Window Tracking)

cargo run --bin ipc_server_demo

This starts the main server that:

• Tracks all windows in real-time using WinEvents
• Publishes window details and grid state via IPC
• Shows periodic grid updates and window counts
• Handles client commands for window assignment
• Uses minimal WinEvent callbacks to prevent deadlocks
• Performs heavy processing in main server loop (every 2 seconds)

2. Start the Client (Grid Visualization & Control)

# In a separate terminal
cargo run --bin grid_client_demo

This starts the intelligent client that:

• Automatically requests window data from server on startup
• Displays real-time grid updates as windows move
• Shows detailed window information and grid state
• Demonstrates efficient event-driven synchronization
• Uses throttled display updates to prevent UI flooding
• Implements non-blocking grid state checks with try_lock

3. Legacy Interactive Demo

cargo run --bin ipc_demo

Original combined server/client for interactive window assignment.

🎯 Focus Event Tracking

E-Grid now includes comprehensive focus event tracking integrated directly into the main server. This allows applications to monitor window focus changes in real-time without needing a separate focus tracking server.

Features

• ✅ Complete Focus Coverage: Both FOCUSED and DEFOCUSED events
• ✅ Real-Time Detection: Uses Windows WinEvent hooks for instant focus change detection
• ✅ Rich Event Data: Process ID, window title, app hash, timestamps
• ✅ Multi-Client Support: Up to 8 simultaneous focus event subscribers
• ✅ Production Ready: Integrated into main e_grid server infrastructure
• ✅ Hash-Based Filtering: Efficient app and window identification

Focus Event Structure

pub struct WindowFocusEvent {
    pub event_type: u8,           // 0 = FOCUSED, 1 = DEFOCUSED
    pub hwnd: u64,               // Window handle
    pub process_id: u32,         // Process ID
    pub timestamp: u64,          // Unix timestamp
    pub app_name_hash: u64,      // Hash of "Process_{pid}" for identification
    pub window_title_hash: u64,  // Hash of window title for identification
    pub reserved: [u8; 2],       // Future expansion
}

Quick Start - Focus Tracking

Method 1: Using Main Server (Recommended)

# Terminal 1: Start main server with focus events
cargo run --bin ipc_server_demo

# Terminal 2: Start focus demo client  
cargo run --example simple_focus_demo

Method 2: Using Test Scripts

# Windows - Automated setup
test_focus_defocus.bat

# Or comprehensive integration test
test_focus_integration.bat

Focus Event Examples

The system includes several focus tracking examples:

• simple_focus_demo: Basic focus event monitoring with clear output
• comprehensive_focus_demo: Advanced focus tracking with filtering and statistics
• focus_tracking_demo: Demonstrates focus event callback patterns
• focus_music_demo: Example integration with MIDI/music applications

Integration with Applications

use e_grid::GridClient;

let mut client = GridClient::new()?;

// Set up focus callback
client.set_focus_callback(|focus_event| {
    match focus_event.event_type {
        0 => println!("Window {} gained focus", focus_event.hwnd),
        1 => println!("Window {} lost focus", focus_event.hwnd),
        _ => {}
    }
})?;

// Start monitoring
client.start_background_monitoring()?;

Key Architecture Features:

• 🎯 NEW: Focus Event Integration: Real-time focus/defocus event publishing
• Deadlock Prevention: WinEvent callbacks only log events, no lock acquisition
• Main Loop Processing: All heavy work done in server main loop (every 2 seconds)
• Multi-Service IPC: Separate channels for different event types
• Non-blocking Client: Uses try_lock and display throttling for responsive UI
• Event-Driven Updates: Server publishes incremental changes, not full state dumps
• Efficient IPC: Large buffer sizes (64KB) prevent message loss

📡 IPC Services

The e_grid server provides multiple IPC services for different types of communication:

Service	Purpose	Message Type	Description
Grid Events	Window lifecycle	WindowEvent	Window creation, destruction, movement
Window Details	Window information	WindowDetails	Position, size, grid coordinates, titles
🎯 Focus Events	Focus tracking	WindowFocusEvent	Focus/defocus with process info ⭐
Commands	Client requests	WindowCommand	Window assignment, grid requests
Responses	Server replies	WindowResponse	Command acknowledgments, data
Layout	Grid layouts	GridLayoutMessage	Save/restore window arrangements
Animations	Window animations	AnimationCommand	Smooth window transitions

Multi-Client Support: Each service supports up to 8 concurrent subscribers with individual message buffers.

🛠️ Available Demos & Tools

Server Applications

# Main server (recommended for all use cases)
cargo run --bin ipc_server_demo

# Legacy interactive server/client combo
cargo run --bin ipc_demo

Grid Client Applications

# Real-time grid visualization
cargo run --bin grid_client_demo

# Enhanced grid client with better error handling
cargo run --example enhanced_grid_client

# Robust grid client with reconnection
cargo run --example robust_grid_client

🎯 Focus Tracking Applications

# Simple focus event monitoring (great for testing)
cargo run --example simple_focus_demo

# Comprehensive focus tracking with filtering
cargo run --example comprehensive_focus_demo

# Focus event callback patterns
cargo run --example focus_tracking_demo

# Focus integration with music/MIDI applications
cargo run --example focus_music_demo

# Focus callback demonstration
cargo run --example focus_callback_example

🎮 Interactive Client Commands

Once the client is running, you can use these commands:

Window Assignment

• assign - Interactive window assignment
  • Choose v for virtual grid (coordinates span all monitors)
  • Choose m for monitor-specific (coordinates relative to individual monitor)
  • Enter window HWND (get from list command)
  • Enter target row and column coordinates

Information Commands

• list - Display all tracked windows with their HWNDs
• grid - Show current grid state for all monitors
• quit - Exit the client

Example Session

[CLIENT] > list
📤 Sent GetWindowList command
📤 [RESPONSE] Window List: 12 windows

[CLIENT] > assign
Choose assignment mode (v=virtual, m=monitor): v
Enter window HWND: 12345678
Enter target row (0-based): 2
Enter target column (0-based): 5
📤 Sent virtual assignment command: HWND 12345678 to (2, 5)

[CLIENT] > grid
📤 Sent GetGridState command
📊 Grid State: 12 windows, 8 occupied cells

🎯 Focus Event Tracking Examples

Simple Focus Demo (simple_focus_demo)

Perfect for testing and learning focus events

cargo run --example simple_focus_demo

Output Example:

🎯 Simple Focus Event Demo
==========================
🟢 FOCUSED - Window: 123456 (PID: 5678) at timestamp: 1640995200
   📱 App Hash: 0x8a2f3c1b5d4e6789
   🪟 Title Hash: 0x1b2c3d4e5f6a7890
   ─────────────────────────────

🔴 DEFOCUSED - Window: 123456 (PID: 5678) at timestamp: 1640995205
   📱 App Hash: 0x8a2f3c1b5d4e6789
   🪟 Title Hash: 0x1b2c3d4e5f6a7890
   ─────────────────────────────

Comprehensive Focus Demo (comprehensive_focus_demo)

Advanced focus tracking with filtering and statistics

• Process-based filtering
• Focus duration tracking
• Application switching patterns
• Statistical analysis

Focus Music Demo (focus_music_demo)

Integration example for music/MIDI applications

• Demonstrates focus event integration with audio applications
• Shows how to use app hash filtering
• Perfect template for e_midi integration

Focus Tracking Architecture

Windows Focus Event
         ↓
EVENT_SYSTEM_FOREGROUND (WinEvent)
         ↓
GridIpcServer::handle_window_event()
         ↓
1. Send DEFOCUSED for previous window
2. Update last_focused_window tracking  
3. Send FOCUSED for current window
         ↓
GRID_FOCUS_EVENTS_SERVICE (IPC)
         ↓
Client Applications (up to 8 simultaneous)

🖥️ Server Commands

The server provides these interactive commands:

• g / grid - Display all monitor grids

• r / rescan - Force rescan of all windows

• e / event - Publish demo IPC event

• c / commands - Process demo IPC commands

• h / help - Show available commands

• q / quit - Exit the server

🎬 Event-Driven Comprehensive Demo

The test_event_driven_demo showcases E-Grid's event-driven architecture with real-time window management:

Key Features

• No Polling: Uses Windows event hooks (SetWinEventHook) for true real-time window detection
• Extensible Callbacks: Event system supports multiple callbacks for window events
• IPC Integration: Demonstrates server/client communication for grid commands
• Main-Thread Safety: All WinEvent processing on main thread to avoid HWND issues
• Manageable Window Filtering: Only shows windows that can be meaningfully managed

Demo Phases

1. Animated Grid Layouts: IPC commands to arrange windows in 2x2 grid with animations
2. Dynamic Window Rotation: Windows rotate through grid positions with smooth transitions
3. Real-time Event Monitoring: 30-second live monitoring of window create/move/destroy events

Running The Demo

# Build and run the event-driven demo
cargo run --bin test_event_driven_demo

# Or use the convenient batch file
run_event_driven_demo.bat

🚧 Future Enhancements

• Window Snapping: Automatic window positioning based on grid assignments
• Configuration System: User-customizable grid sizes and monitor layouts
• Hotkey Integration: Global hotkeys for quick window assignments
• Session Management: Save and restore window layouts
• Tiling Policies: Advanced tiling algorithms and window arrangement patterns

🤝 Contributing

This project demonstrates advanced Rust patterns for:

• Windows API integration
• Inter-process communication
• Multi-monitor handling
• Real-time system integration
• Safe concurrent programming

Perfect foundation for building sophisticated window management tools and desktop environments.

🔍 Troubleshooting

Single-Cell Assignment Issues

Problem: "When I assign a window to one cell, it shows up in multiple cells"

Solution: This has been resolved with the coverage-based detection system. The new algorithm:

• Calculates exact intersection areas between windows and cells
• Only marks cells as occupied when coverage exceeds 30% threshold
• Ensures single-cell assignments appear in only the target cell

Adjusting Sensitivity: If you need different behavior, modify the coverage threshold:

// In src/lib.rs - make more or less sensitive
const COVERAGE_THRESHOLD: f32 = 0.5; // Increase for stricter detection
const COVERAGE_THRESHOLD: f32 = 0.1; // Decrease for more sensitive detection

Grid Display Accuracy

The grid now accurately reflects window positions:

• ✅ Single-cell assignments show up in exactly one cell
• ✅ Large windows may span multiple cells based on actual coverage
• ✅ Small windows only occupy cells they significantly overlap
• ✅ Boundary cases are handled intelligently with area calculations

NOTICE: This repository is in an interesting state; the examples and functionality may or may not be implemented. Have a look at the e_midi which includes an example of playing a midi sound using the focus and defocused events. Aside from that; Feel free to take a look at the LLM cruft, it will give you an idea of some of the directions this project could go.

Dave Horner 6/25 MIT/Apache License