🖥️ Delphi Remote Desktop Components

Professional Desktop Duplication Components for Delphi with Network Streaming & Intelligent Dirty Pixel Detection

High-performance DXGI-based desktop capture components with intelligent dirty pixel detection, network streaming capabilities, and automatic fallback to GDI

Preview Images:

🚀 Overview

Delphi_DesktopCapture provides two powerful, professional-grade desktop capture components built on Windows Desktop Duplication API (DXGI) with intelligent dirty pixel detection, automatic format optimization, network-ready TBytes streaming, and seamless GDI fallback. Perfect for remote desktop applications, screen sharing, surveillance software, live streaming, and real-time desktop monitoring.

🎯 What's Included

🖥️ TDesktopCapture Component - Professional desktop duplication with intelligent dirty region detection
📺 TDesktopCaptureReceiver Component - High-performance frame reconstruction and display
🔄 Smart Frame Management - Full frame first, then dirty pixels only for maximum efficiency
🌐 Network-Ready Design - TBytes-based callbacks for seamless network integration
🎯 Cursor Integration - Optional cursor capture with proper alpha blending
📦 Ready-to-Install Package - Complete component package for Delphi IDE
⚡ DXGI + GDI Fallback - Maximum compatibility across all Windows versions

🏗️ Architecture

graph TD
    A[Desktop] --> B[DXGI Desktop Duplication]
    B --> C{DXGI Available?}
    C -->|Yes| D[High-Performance Capture]
    C -->|No| E[GDI Fallback]
    D --> F[TDesktopCapture]
    E --> F
    F --> G{First Frame?}
    G -->|Yes| H[Send Full Frame]
    G -->|No| I[Dirty Detection]
    H --> J[Store Base Frame]
    I --> K{Changes Found?}
    K -->|Yes| L[Send Dirty Regions]
    K -->|No| M[Skip Frame]
    L --> N[TBytes Network Stream]
    H --> N
    N --> O[TDesktopCaptureReceiver]
    O --> P{Frame Type?}
    P -->|Full| Q[Replace Base Frame]
    P -->|Dirty| R[Apply Dirty Regions]
    Q --> S[Update Display]
    R --> S
    S --> T[Target Image/Bitmap]

⭐ Key Features

🖥️ TDesktopCapture Component

DXGI Desktop Duplication - Native Windows desktop duplication API for zero-copy capture
Intelligent Dirty Detection - Advanced block-based algorithm detects only changed screen regions
Full Frame + Dirty Mode - Sends complete screen first, then only pixel changes thereafter
Automatic GDI Fallback - Seamless fallback to GDI on older systems or DXGI failures
High-Performance Threading - Non-blocking capture with configurable frame rates
Network-Optimized Output - TBytes format perfect for network transmission
Cursor Capture - Optional high-quality cursor integration with alpha blending
Resolution Change Detection - Automatic handling of display resolution changes

📺 TDesktopCaptureReceiver Component

Smart Frame Reconstruction - Efficiently rebuilds full desktop from dirty regions
Base Frame Management - Maintains complete desktop state for dirty region application
Display Integration - Direct TImage component integration for easy UI development
Thread-Safe Operation - Proper synchronization for multi-threaded network applications
Memory Efficient - Intelligent buffer management prevents memory leaks
Error Resilient - Graceful handling of corrupted or incomplete frame data

🎯 Intelligent Dirty Detection

Block-Based Analysis - 32x32 pixel blocks for optimal performance vs. accuracy
Pixel Sampling - Strategic pixel sampling reduces CPU usage while maintaining accuracy
Change Threshold - Smart detection prevents false positives from minor variations
Region Optimization - Coalesces adjacent dirty blocks into larger regions
Skip Empty Frames - Automatically skips transmission when no changes detected

🛠️ Technical Excellence

Dual Capture Methods - DXGI for performance, GDI for compatibility
Format Flexibility - 32-bit BGRA pixel format with proper stride handling
Memory Efficient - Smart buffer allocation and proper cleanup procedures
Error Resilient - Comprehensive error handling and graceful degradation
Performance Optimized - Direct memory operations for maximum throughput

📦 Installation

Prerequisites

Delphi XE2 or later
Windows Vista+ (DXGI requires Windows 8+ for best performance)
NetCom7 components (recommended) - For network streaming examples

Installation Steps

Extract components to your Delphi components directory
Open DesktopCaptureComponents.dpk in Delphi IDE
Build and Install the package
Add "RequiredHeaders" Folder to your IDE's Library path 32bit and 64bit paths if you plan to make both 32bit and 64bit binaries!
Also do not forget to do the same 32bit library path and 64bit library paths for the main components themselves in the "DesktopCaptureComponents" folder.
Components appear on "Desktop Capture" tab simply drag and drop to use them!

🚀 Usage Examples

Basic Desktop Capture with Dirty Detection

procedure TForm1.FormCreate(Sender: TObject);
begin
  DesktopCapture1.Mode := cmDirtyOnly;
  DesktopCapture1.OnFrameCaptured := OnFrameCaptured;
  DesktopCapture1.Active := True;
end;

procedure TForm1.OnFrameCaptured(Sender: TObject; const FrameData: TBytes; IsFullFrame: Boolean);
begin
  // That's it - FrameData contains everything needed
  // First frame = full screen, subsequent = dirty regions only
end;

Local Desktop Display with Receiver

procedure TForm1.FormCreate(Sender: TObject);
begin
  DesktopCapture1.OnFrameCaptured := OnLocalFrame;
  DesktopCapture1.Active := True;
  DesktopReceiver1.TargetImage := Image1;
end;

procedure TForm1.OnLocalFrame(Sender: TObject; const FrameData: TBytes; IsFullFrame: Boolean);
begin
  DesktopReceiver1.ReceiveFrameData(FrameData);
end;

Network Desktop Streaming (Sender)

// Sender Side - ONE LINE to send over NetCom7
procedure TForm1.OnFrameCaptured(Sender: TObject; const FrameData: TBytes; IsFullFrame: Boolean);
begin
  NetCom7Client.ExecCommand(1, FrameData);  // DONE!
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  DesktopCapture1.OnFrameCaptured := OnFrameCaptured;
  DesktopCapture1.Active := True;
end;

Network Desktop Streaming (Receiver)

// Receiver Side - ONE LINE to receive and display
procedure TForm1.NetCom7Server1ExecCommand(Sender: TObject; Socket: TCustomWinSocket; 
  const Command: Integer; Data: TBytes);
begin
  if Command = 1 then
    DesktopReceiver1.ReceiveFrameData(Data);  // DONE!
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  DesktopReceiver1.TargetImage := Image1;
  NetCom7Server1.Start;
end;

Complete Remote Desktop Application

// CLIENT (Sender) - Complete in 4 lines
procedure TForm1.FormCreate(Sender: TObject);
begin
  DesktopCapture1.OnFrameCaptured := procedure(Sender: TObject; const FrameData: TBytes; IsFullFrame: Boolean)
    begin NetCom7Client.ExecCommand(1, FrameData); end;
  DesktopCapture1.Active := True;
  NetCom7Client.Connect('192.168.1.100', 8080);
end;

// SERVER (Receiver) - Complete in 3 lines  
procedure TForm1.NetCom7Server1ExecCommand(Sender: TObject; Socket: TCustomWinSocket; 
  const Command: Integer; Data: TBytes);
begin
  if Command = 1 then DesktopReceiver1.ReceiveFrameData(Data);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  DesktopReceiver1.TargetImage := Image1;
  NetCom7Server1.Start;
end;

Different Use Cases - Simple Configuration

// High FPS for gaming/recording
DesktopCapture1.TargetFPS := 60;
DesktopCapture1.Mode := cmFullFrame;

// Bandwidth efficient for remote desktop  
DesktopCapture1.TargetFPS := 20;
DesktopCapture1.Mode := cmDirtyOnly;

// Low bandwidth surveillance
DesktopCapture1.TargetFPS := 5;
DesktopCapture1.Mode := cmDirtyOnly;
DesktopCapture1.IncludeCursor := False;

🎛️ Component Properties

TDesktopCapture Properties

Property	Type	Default	Description
Active	Boolean	False	Start/stop desktop capture
Method	TCaptureMethod	cmDXGI	Capture method (DXGI or GDI)
Mode	TCaptureMode	cmDirtyOnly	Frame mode (Full frames or dirty regions)
TargetFPS	Integer	30	Target capture frame rate (1-120)
IncludeCursor	Boolean	True	Include mouse cursor in capture

TDesktopCapture Events

Event	Description
OnFrameCaptured	Fired when frame data is captured (TBytes format, IsFullFrame flag)

TDesktopCaptureReceiver Properties

Property	Type	Default	Description
Active	Boolean	True	Enable frame processing
TargetImage	TImage	nil	Target TImage component for display
CurrentWidth	Integer	Read-only	Current frame width
CurrentHeight	Integer	Read-only	Current frame height

TDesktopCaptureReceiver Events

Event	Description
OnFrameReceived	Fired when frame is processed (Width, Height parameters)

TDesktopCaptureReceiver Methods

Method	Description
ReceiveFrameData(FrameData: TBytes)	Process received frame data
ClearDisplay	Clear current display and reset state
HasValidFrame: Boolean	Check if valid frame data exists

🎯 How Smart Dirty Detection Works

Initial Full Frame

// First capture always sends complete desktop
OnFrameCaptured(Sender, FullScreenBytes, True);  // IsFullFrame = True
// Receiver stores this as base frame for dirty region application

Subsequent Dirty Frames

// Component compares current screen with previous frame
// Detects changed 32x32 pixel blocks
// Sends only the changed regions + coordinates
OnFrameCaptured(Sender, DirtyRegionBytes, False); // IsFullFrame = False
// Receiver applies dirty regions to base frame

Bandwidth Efficiency Example

Full Frame: 1920x1080x4 = 8,294,400 bytes
Typical Dirty Frame: 50 changed blocks = ~200,000 bytes
Bandwidth Reduction: ~97% for typical desktop usage

🎯 Use Cases

🏢 Business & Enterprise

Remote Desktop Solutions - Full-featured remote desktop with cursor support
Screen Sharing Applications - Low-latency screen sharing for meetings
Digital Signage - Efficient content distribution to multiple displays
Helpdesk Support - Remote assistance with minimal bandwidth usage
Presentation Broadcasting - Share presentations with minimal network impact

🎮 Development & Gaming

Game Streaming - Efficient game screen capture and streaming
Development Tools - Screen sharing for collaborative development
Testing Frameworks - Automated UI testing with screen capture
Live Streaming Software - Professional desktop capture for streaming
Remote Debugging - Share debug sessions across team members

🎓 Educational & Training

Online Learning Platforms - Teacher screen sharing with students
Training Software - Capture and replay training sessions
Tutorial Creation - High-quality screen recording for tutorials
Remote Classroom - Interactive online classroom experiences
Software Demonstrations - Efficient demo sharing and recording

🛡️ Security & Monitoring

Desktop Surveillance - Monitor desktop activity with minimal storage
Session Recording - Record user sessions for compliance
Security Monitoring - Real-time desktop monitoring for security
Activity Logging - Efficient desktop activity capture and storage
Forensic Analysis - Capture desktop state for later analysis

🔧 Technical Implementation Details

DXGI Desktop Duplication

// The component uses Windows Desktop Duplication API
IDXGIOutputDuplication.AcquireNextFrame()  // Zero-copy desktop access
// Benefits:
// - Hardware accelerated
// - Minimal CPU usage  
// - Perfect pixel accuracy
// - Automatic dirty region hints from Windows

Intelligent Dirty Detection Algorithm

// 1. Divide screen into 32x32 pixel blocks
// 2. Sample every 2nd pixel in each block for performance
// 3. Compare with previous frame blocks
// 4. Mark changed blocks as dirty regions
// 5. Coalesce adjacent dirty blocks
// 6. Send only dirty region pixel data + coordinates

Frame Data Format

TFrameHeader = packed record
  IsFullFrame: Boolean;        // True = full screen, False = dirty regions
  Width: Integer;              // Frame width
  Height: Integer;             // Frame height  
  DataSize: Integer;           // Pixel data size in bytes
  DirtyRegionCount: Integer;   // Number of dirty regions (0 for full frame)
end;
// Followed by dirty region coordinates (if any)
// Followed by pixel data (BGRA format)

Network Protocol Integration

// Perfect for network streaming protocols:
// 1. Capture sends TBytes via OnFrameCaptured
// 2. Transmit TBytes over any network protocol
// 3. Receiver processes TBytes via ReceiveFrameData()
// 4. Automatic frame reconstruction and display

📈 Performance Specifications

Capture Performance

DXGI Method: <1ms capture time on modern hardware
GDI Method: 5-15ms capture time (compatibility fallback)
Dirty Detection: <2ms for 1920x1080 desktop
Memory Usage: <50MB for typical operation
CPU Usage: <5% on modern CPUs with DXGI

Network Efficiency

Full Frame: ~8MB for 1920x1080 (uncompressed)
Typical Dirty Frame: 50KB-500KB depending on activity
Bandwidth Reduction: 90-99% vs. continuous full frames
Frame Rates: 1-120 FPS configurable
Latency: <50ms end-to-end on local network

Supported Configurations

Resolutions: Any Windows-supported resolution
Multi-Monitor: Primary display capture
Pixel Format: 32-bit BGRA (4 bytes per pixel)
Windows Versions: Vista+ (Windows 8+ recommended for DXGI)

🧪 Testing & Quality

Automated Tests

Component Installation - Package builds and installs correctly in all supported Delphi versions
DXGI Initialization - Desktop duplication initializes properly on Windows 8+
GDI Fallback - Automatic fallback works when DXGI unavailable
Dirty Detection Accuracy - Changed regions detected correctly
Memory Management - No memory leaks during extended operation
Network Integration - TBytes format works correctly with network components
Resolution Changes - Handles display resolution changes gracefully

Manual Testing Checklist

Components appear in IDE after installation
Desktop capture produces valid frame data
Dirty detection works accurately
Full frame sent first, dirty regions thereafter
Cursor capture functions properly
Receiver reconstructs frames correctly
Network streaming maintains quality
Performance remains stable during extended use
Error handling works for various failure scenarios

🛠️ Compatibility

Delphi Versions

Delphi XE2 - Full compatibility
Delphi XE3-XE8 - Full compatibility
Delphi 10.x Seattle+ - Full compatibility
Delphi 11.x Alexandria - Full compatibility
Delphi 12.x Athens - Full compatibility

Windows Versions

Windows Vista/7 - GDI capture method (DXGI not available)
Windows 8/8.1 - Full DXGI support, recommended
Windows 10 - Full support with optimal performance
Windows 11 - Full support with latest features

🤝 Contributing

Contributions welcome!

📝 License

This project is licensed under the MIT License - see the LICENSE file for complete details.

👨‍💻 Author

BitmasterXor

GitHub: @BitmasterXor
Discord: BitmasterXor

🙏 Acknowledgments

Microsoft DXGI Team - Desktop Duplication API for efficient screen capture
Delphi Community - Continuous support and inspiration
Desktop Duplication Developers - Best practices and optimization techniques
Beta Testers - Critical feedback during component development
NetCom7 Contributors - Networking components that integrate perfectly
Performance Testers - Feedback on dirty detection algorithms and efficiency

📚 Additional Resources

Documentation

Example Projects

Basic local desktop display and capture
Network desktop streaming (client/server)

⭐ Star this repository if these components help your desktop capture projects!

Made with ❤️ By BitmasterXor For the Delphi Community

Name		Name	Last commit message	Last commit date
Latest commit History 31 Commits
DesktopCaptureComponents		DesktopCaptureComponents
.gitignore		.gitignore
LICENSE		LICENSE
Preview1.png		Preview1.png
Preview2.png		Preview2.png
README.md		README.md

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