v1.2.0 - VCL Support

🎉 Release v1.2.0 - VCL Support

Major Features

• ✅ Full VCL support with TPdfViewer component for Windows
• ✅ Separate renderer architecture for FMX and VCL
• ✅ VCL demo application with drag-and-drop support

VCL Improvements

• 🎨 Proper aspect ratio preservation in PDF rendering
• 🎯 Centered display with light gray background for better visibility
• 🔄 Smooth resizing without artifacts
• ⚡ Background rendering with loading indicator
• 📐 High DPI support for modern displays

Technical Changes

• 🏗️ Refactored core viewer logic into shared TPdfViewerCore base class
• 🎨 Platform-specific renderers (DX.Pdf.Renderer.FMX and DX.Pdf.Renderer.VCL)
• 🔒 Improved thread safety with TThread.Synchronize
• 🛡️ Better error handling in rendering pipeline

Demo Applications

• 📱 FMX PDF Viewer - Cross-platform (Windows, macOS, Android, iOS)
• 🖥️ VCL PDF Viewer - Windows-native with VCL controls
• ⌨️ Both with keyboard navigation and drag-and-drop support

Documentation

• 📖 Updated README with FMX and VCL support details
• 📝 Clarified resource management (automatic cleanup, not reference counting)
• ✅ Added tested Delphi versions (12.3 Athens, 13 Florence)
• ⚠️ Minimum Delphi 10.0 (not tested, no guarantee)

Commits in this Release

• 748dbaa - docs: Update README with FMX and VCL support information
• 9d1a061 - chore: Remove obsolete StreamLoadingComparison example file
• f26bfce - chore(VCL): Add artwork assets for VCL demo application
• a7788bc - chore(VCL): Update VCL project configuration with artwork paths and platform support
• f47e2b2 - chore(FMX): Add missing unit references to FMX demo project
• 7d21508 - chore(VCL): Update VCL demo form with higher DPI settings
• a5b74d4 - feat(VCL): Improve PDF rendering with proper aspect ratio and centered display

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Full Changelog: v1.1.0...v1.2.0

v1.1.0 - Efficient Stream Loading Support

🚀 New Features

Efficient Stream Loading with LoadFromStream

• True streaming support using PDFium's FPDF_LoadCustomDocument API
• Zero-copy streaming - PDFium reads data blocks on-demand via callbacks
• Stream ownership management - optional automatic cleanup with AOwnsStream parameter
• Memory efficient - no duplication of PDF data in memory
• Ideal for large PDFs, network streams, and memory-constrained scenarios

📊 Performance Improvements

• ~50% memory reduction for stream-based loading compared to previous implementation
• Stream data is read on-demand, not loaded entirely into memory
• Efficient for large PDF files (100+ MB)

🔧 API Changes

New Stream Loading API

procedure LoadFromStream(AStream: TStream; AOwnsStream: Boolean = False; const APassword: string = '');

New in TPdfDocument:

• LoadFromStream - Now uses efficient streaming (replaces old memory-based implementation)
• TPdfStreamAdapter - New adapter class bridging TStream to PDFium callbacks

New in TPdfViewer:

• LoadFromStream - Updated to use efficient streaming

New in DX.Pdf.API:

• FPDF_FILEACCESS - Structure for custom file access
• TFPDFFileAccessGetBlock - Callback function type
• FPDF_LoadCustomDocument - PDFium API binding for streaming

📚 Documentation & Examples

Usage Examples

Option A: Keep stream ownership (manual cleanup)

LStream := TMemoryStream.Create;
try
  LStream.LoadFromFile('document.pdf');
  PdfViewer.LoadFromStream(LStream, False);  // You manage the stream
  // Stream must remain valid until document is closed!
finally
  LStream.Free;  // You free the stream
end;

Option B: Transfer ownership (recommended)

LStream := TMemoryStream.Create;
LStream.LoadFromFile('document.pdf');
PdfViewer.LoadFromStream(LStream, True);  // Viewer owns the stream
// Viewer will free the stream automatically on Close()
// DO NOT free LStream yourself!

Real-world scenarios

• HTTP downloads - Stream PDF directly from web without saving to disk
• Database BLOBs - Load PDFs from database fields
• Encrypted containers - Decrypt on-the-fly while streaming
• Large files - Handle 100+ MB PDFs efficiently

✅ Testing

• 19 unit tests - All passing ✅
• 5 new streaming tests:
  • TestLoadFromStreamBasic - Basic streaming functionality
  • TestLoadFromStreamWithOwnership - Stream ownership transfer
  • TestLoadFromStreamSeekable - Multiple seeks verification
  • TestLoadFromStreamNoMemoryDuplication - Zero-copy verification
  • TestStreamAdapterCallback - Callback execution verification
• No memory leaks - Verified with DUnitX memory leak detection
• Proper cleanup - Stream adapter lifecycle managed by TPdfDocument

🔄 Migration Guide

Before (v1.0.0)

LStream := TMemoryStream.Create;
try
  LStream.LoadFromFile('document.pdf');
  PdfViewer.LoadFromStream(LStream);  // Loaded entire PDF into memory
finally
  LStream.Free;
end;

After (v1.1.0)

// Same code works, but now with efficient streaming!
LStream := TMemoryStream.Create;
try
  LStream.LoadFromFile('document.pdf');
  PdfViewer.LoadFromStream(LStream, False);  // Efficient streaming
finally
  LStream.Free;
end;

// Or use ownership transfer for cleaner code:
LStream := TMemoryStream.Create;
LStream.LoadFromFile('document.pdf');
PdfViewer.LoadFromStream(LStream, True);  // Auto-cleanup

Note: The new AOwnsStream parameter defaults to False for backwards compatibility.

🛠️ Internal Improvements

• Removed FMemoryBuffer: TBytes field (no longer needed)
• Added FStreamAdapter: TPdfStreamAdapter for streaming support
• Implemented exception-safe callback mechanism
• Proper cleanup in Close() method
• Optimized build scripts (removed blocking pause commands)

📦 Technical Details

How it works

1. TPdfStreamAdapter wraps a Delphi TStream
2. Provides FPDF_FILEACCESS structure with callback function pointer
3. PDFium calls GetBlockCallback to read data blocks on-demand
4. Callback performs Seek + Read operations on the stream
5. No memory duplication - PDFium reads directly from stream

Callback Implementation

class function TPdfStreamAdapter.GetBlockCallback(param: Pointer; 
  position: Cardinal; pBuf: PByte; size: Cardinal): Integer; cdecl;
var
  LAdapter: TPdfStreamAdapter;
  LBytesRead: Integer;
begin
  Result := 0;
  if param = nil then Exit;
  LAdapter := TPdfStreamAdapter(param);
  try
    LAdapter.FStream.Position := position;
    LBytesRead := LAdapter.FStream.Read(pBuf^, size);
    if LBytesRead = Integer(size) then
      Result := 1  // Success
    else
      Result := 0;  // Failure
  except
    Result := 0;  // Error
  end;
end;

🔗 Comparison: v1.0.0 vs v1.1.0

Aspect	v1.0.0	v1.1.0
Stream Loading	Entire PDF in memory	On-demand streaming
Memory Usage (100MB PDF)	~200 MB (2x during load)	~100 MB (1x)
Large PDFs (>100MB)	⚠️ Not recommended	✅ Efficient
Stream Ownership	Manual only	Manual or automatic
API Complexity	Simple	Simple + flexible

📝 Full Changelog

Commits:

• dc1cf12 - Simplify API: Replace LoadFromStreamEx with improved LoadFromStream
• ddfd028 - Implement true streaming support with FPDF_LoadCustomDocument

Files Changed:

• src/DX.Pdf.API.pas - Added PDFium streaming API bindings
• src/DX.Pdf.Document.pas - Implemented TPdfStreamAdapter and efficient LoadFromStream
• src/DX.Pdf.Viewer.FMX.pas - Updated LoadFromStream signature
• src/tests/DX.Pdf.Document.Tests.pas - Added 5 new streaming tests
• examples/StreamLoadingComparison.pas - Updated examples
• src/tests/build-and-run-tests.bat - Removed blocking pause commands

Statistics:

• Lines added: +43
• Lines removed: -180
• Net change: -137 lines (simpler, cleaner code!)

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Full Changelog: v1.0.0...v1.1.0

v1.0.0 - Initial Public Release

DX Pdfium4D v1.0.0 - Initial Public Release

🎉 First stable release of DX Pdfium4D - A comprehensive Delphi wrapper for Google's PDFium library!

🚀 Features

Core Wrapper

• ✅ Object-oriented API - High-level Delphi classes wrapping PDFium C-API
• ✅ Automatic resource management - Reference counting prevents memory leaks
• ✅ Type-safe error handling - Exception-based error handling
• ✅ Cross-platform support - Windows, macOS, Android, iOS

PDF Document Support

• 📄 Load PDF documents from files or memory
• 📋 Extract metadata (title, author, subject, keywords)
• 🎯 PDF/A compliance detection
• 📏 Page count and dimensions
• 🎨 High-quality bitmap rendering with configurable DPI

Components & Tools

• 🖼️ FMX Visual Component - Ready-to-use PDF viewer component
• 📱 Example Application - DX PDF Viewer with drag & drop support
• ✅ Unit Tests - Comprehensive test suite using DUnitX
• 📚 Sample PDF Files - Test files from PDF Association

📦 What's Included

• DX.Pdf.API.pas - Low-level PDFium C-API bindings
• DX.Pdf.Document.pas - High-level document/page classes
• DX.Pdf.Viewer.FMX.pas - FMX visual component
• DX PDF Viewer - Complete example application
• Unit Tests - DUnitX test suite
• Sample PDFs - Example files for testing
• Documentation - Comprehensive README and usage guide

🎯 Getting Started

uses
  DX.Pdf.Document;

var
  LDocument: TPdfDocument;
  LPage: TPdfPage;
  LBitmap: TBitmap;
begin
  LDocument := TPdfDocument.Create('document.pdf');
  try
    LPage := LDocument.Pages[0];
    LBitmap := LPage.RenderToBitmap(96); // 96 DPI
    try
      // Use the bitmap
    finally
      LBitmap.Free;
    end;
  finally
    LDocument.Free;
  end;
end;

📋 Requirements

• Delphi 12 or later (tested with Delphi 12.2 Athens)
• Minimum: Delphi XE2 (for FireMonkey support)
• Recommended: Delphi 10.x or later

📖 Documentation

See USING_DX_PDF.md for detailed usage instructions.

🙏 Acknowledgments

• Google - PDFium library
• Benoît Blanchon - PDFium binaries
• PDF Association - Sample PDF files
• VSoft Technologies - DUnitX testing framework

📄 License

MIT License - Free for commercial and open-source projects

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Full Changelog: https://github.com/omonien/DX.Pdfium4D/commits/v1.0.0