Hello World from Delphi HotPDF Component

Welcome to the comprehensive guide for the Delphi HotPDF Component HelloWorld demonstration program!

About HotPDF Component

HotPDF Component is a powerful and versatile PDF processing library designed specifically for Delphi and C++Builder developers. This comprehensive component provides an extensive API that enables developers to create, manipulate, and modify PDF documents with ease and precision.

Key Features of HotPDF Component:

• PDF Creation & Generation: Create PDF documents from scratch with full control over layout, formatting, and content
• Text & Graphics Support: Add text, images, shapes, and complex graphics to PDF pages
• Multilingual Support: Full Unicode support for international text rendering
• Font Management: Embed fonts for consistent document appearance across different systems
• Compression Options: Multiple compression algorithms to optimize file size
• Security Features: Document encryption, password protection, and permission controls
• Document Manipulation: Merge, split, and modify existing PDF documents
• Table & Form Support: Create complex tables and interactive forms

HelloWorld.dpr Program Overview

The HelloWorld.dpr example program serves as an excellent introduction to the HotPDF Component’s
most basic and important feature: The TexOut function. This demonstration program
also showcases the basic PDF creation functionality.

Core Functionality:

1. PDF Document Creation

The program’s primary function is to generate PDF documents containing multilingual “Hello World” text. The CreatePDF procedure demonstrates:

• Component Initialization: Proper setup and configuration of the THotPDF component
• Document Properties: Setting metadata such as compression options and font embedding
• Multilingual Text Rendering: Displaying text in 11 different languages including English, Spanish, German, French, Italian, Portuguese, Russian, Japanese, Turkish, Chinese, and Korean
• Font Management: Using Arial Unicode MS for most languages and Malgun Gothic for Korean text
• Compression Comparison: Creating both compressed and uncompressed versions to demonstrate file size differences

2. Window Management & System Integration

The program includes sophisticated window enumeration functionality that demonstrates:

• System Window Enumeration: Using the Windows API EnumWindows function to iterate through all top-level windows
• Window Title Matching: Implementing substring matching to identify target applications
• Automated Window Closure: Sending WM_CLOSE messages to close PDF viewers that might have files open
• Conflict Prevention: Ensuring no file access conflicts occur when creating new PDF files

3. Error Handling & Resource Management

The program demonstrates best practices for:

• Memory Management: Proper creation and disposal of component instances
• Exception Safety: Using try-finally blocks to ensure resource cleanup
• User Feedback: Providing console output to inform users of program progress

Technical Implementation Details:

Compression Technology

The program creates two versions of the same PDF to demonstrate the effectiveness of FlateDecode compression:

• Uncompressed Version: Faster creation time, larger file size
• Compressed Version: Slightly longer creation time, significantly smaller file size

Font Handling Strategy

The program employs a sophisticated font selection strategy:

• Arial Unicode MS: Used for most languages due to its broad character support
• Malgun Gothic Semilight: Specifically chosen for Korean text rendering
• Font Embedding: Ensures consistent appearance across different systems

Cross-Version Compatibility

The code includes conditional compilation directives to support both modern and legacy Delphi versions:

• XE2+ Support: Uses namespaced units (WinApi.Windows, System.SysUtils, etc.)
• Legacy Support: Falls back to traditional unit names for older Delphi versions
• EurekaLog Integration: Optional memory leak detection and debugging support

Educational Value

This HelloWorld example serves multiple educational purposes:

• Component Introduction: Provides a gentle introduction to HotPDF Component usage
• Best Practices: Demonstrates proper resource management and error handling
• System Integration: Shows how to integrate PDF generation with Windows system operations
• Internationalization: Illustrates multilingual text handling in PDF documents
• Performance Considerations: Compares different compression strategies and their trade-offs

Getting Started

To run this example program:

1. Ensure HotPDF Component is properly installed in your Delphi IDE
2. Open the HelloWorld.dpr project file
3. Compile and run the program
4. The program will automatically create two PDF files demonstrating compression differences
5. Examine the generated files to see the multilingual text rendering and compare file sizes

Source Code

Below is the complete, well-documented source code for the HelloWorld demonstration program:

{************************************************************}
// HotPDF PDF Component
// Copyright(c)2007-2025, https://www.loslab.com
{************************************************************}
// HelloWorld Demo Program for HotPDF Component
// This program demonstrates basic PDF creation capabilities
// including multilingual text support and compression options
{************************************************************}

program HelloWorld;
{$APPTYPE CONSOLE}  // Console application type
{$I ..\..\..\Lib\HotPDF.inc}  // Include HotPDF configuration file

uses
  // EurekaLog units for memory leak detection and debugging (optional)
  {$IFDEF EurekaLog}
  EMemLeaks,          // Memory leak detection
  EResLeaks,          // Resource leak detection
  EDebugJCL,          // JCL debugging support
  EDebugExports,      // Export debugging information
  EFixSafeCallException, // SafeCall exception handling
  EMapWin32,          // Win32 mapping support
  EAppConsole,        // Console application support
  EDialogConsole,     // Console dialog support
  ExceptionLog7,      // Exception logging
  {$ENDIF EurekaLog}
  // System units - different namespaces for XE2+ vs older versions
  {$IFDEF XE2+}
  WinApi.Windows,     // Windows API functions
  WinApi.Messages,    // Windows message constants
  System.SysUtils,    // System utilities
  System.Classes,     // Base classes (TStringList, etc.)
  Vcl.Graphics,       // Graphics support
  {$ELSE}
  Windows,            // Windows API functions (older Delphi)
  Messages,           // Windows message constants (older Delphi)
  SysUtils,           // System utilities (older Delphi)
  Classes,            // Base classes (older Delphi)
  Graphics,           // Graphics support (older Delphi)
  {$ENDIF}
  HPDFDoc;            // HotPDF main component unit

// Creates a PDF file with multilingual "Hello World" text
// Parameters:
//   FileName: Output PDF file name
//   UseCompression: True to enable FlateDecode compression, False for no compression
procedure CreatePDF(const FileName: string; UseCompression: Boolean);
var
  HotPDF: THotPDF;  // Main HotPDF component instance
begin
  // Create HotPDF component instance
  HotPDF := THotPDF.Create(nil);
  try
    // Configure PDF properties
    HotPDF.AutoLaunch := true;        // Automatically open PDF after creation
    HotPDF.FileName := FileName;      // Set output file name

    // Set compression based on parameter
    if UseCompression then
    begin
      HotPDF.Compression := cmFlateDecode;  // Enable FlateDecode compression
      WriteLn('Creating compressed PDF: ', FileName);
    end
    else
    begin
      HotPDF.Compression := cmNone;         // No compression
      WriteLn('Creating uncompressed PDF: ', FileName);
    end;

    HotPDF.FontEmbedding := true;     // Embed fonts for better compatibility
    HotPDF.BeginDoc;                  // Start PDF document creation

    // Set Unicode font for multilingual text support
    // Arial Unicode MS supports most languages except Korean
    // procedure SetFont ( FontName: AnsiString; FontStyle: TFontStyles; ASize: Single; FontCharset: TFontCharset = DEFAULT_CHARSET; IsVertical: boolean = false);
    // DEFAULT_CHARSET: 1 - Font is chosen based on Name. If the described font is not available on the system, Windows will substitute another font
    HotPDF.CurrentPage.SetFont('Arial Unicode MS', [], 12, 1, False);
    
    // Display "Hello World" in multiple languages
    // TextOut parameters: (X, Y, Angle, Text)
    HotPDF.CurrentPage.TextOut(80, 50, 0, 'Hello, Delphi PDF world!');      // English
    HotPDF.CurrentPage.TextOut(80, 70, 0, 'Hola, mundo Delphi PDF!');       // Spanish
    HotPDF.CurrentPage.TextOut(80, 90, 0, 'Hallo, Delphi PDF Welt!');       // German
    HotPDF.CurrentPage.TextOut(80, 110, 0, 'Bonjour, monde PDF Delphi!');   // French
    HotPDF.CurrentPage.TextOut(80, 130, 0, 'Ciao, mondo Delphi PDF!');      // Italian
    HotPDF.CurrentPage.TextOut(80, 150, 0, 'Olá, mundo Delphi PDF!');       // Portuguese
    HotPDF.CurrentPage.TextOut(80, 170, 0, 'Здравствуйте, Delphi PDF мир!'); // Russian
    HotPDF.CurrentPage.TextOut(80, 190, 0, 'こんにちは、Delphi PDFの世界！');    // Japanese
    HotPDF.CurrentPage.TextOut(80, 210, 0, 'Merhaba, Delphi PDF dünyası!'); // Turkish
    HotPDF.CurrentPage.TextOut(80, 230, 0, '你好，Delphi PDF世界');           // Chinese
    
    // Korean text requires a specific Korean font
    // Arial Unicode MS doesn't properly support Korean characters
    HotPDF.CurrentPage.SetFont('Malgun Gothic Semilight', [], 12, 0, False);
    HotPDF.CurrentPage.TextOut(80, 250, 0, '여보세요, Delphi PDF 세계!');     // Korean
    
    HotPDF.EndDoc;  // Finalize and save the PDF document
    WriteLn('PDF created successfully: ', FileName);
  finally 
    HotPDF.Free;    // Clean up HotPDF component
  end;
end;

// Global variables for window enumeration and PDF creation
var
  Title: String;                        // Individual title string (unused in current implementation)
  Titles: TStrings;                     // List of window titles to search for
  Window: HWND;                         // Window handle (unused in current implementation)
  WindowText: array[0..255] of Char;    // Buffer for window text (unused in current implementation)
  WindowTitle: String;                  // Window title string (unused in current implementation)
  I: Integer;                           // Loop counter (unused in current implementation)

// Callback function for EnumWindows API
// This function is called for each top-level window in the system
// Parameters:
//   hWnd: Handle to the current window being enumerated
//   lParam: User-defined data (in our case, pointer to TStrings with target titles)
// Returns: True to continue enumeration, False to stop
function EnumWindowsProc(hWnd: HWND; lParam: LPARAM): BOOL; stdcall;
var
  Titles: TStrings;                     // List of target window titles
  I: Integer;                           // Loop counter
  WindowText: array[0..255] of Char;    // Buffer to store window text
  WindowTitle: String;                  // Current window's title as string
begin
  Result := True;                       // Continue enumeration by default
  Titles := TStrings(lParam);           // Cast lParam back to TStrings
  
  // Get the window title text
  if GetWindowText(hWnd, WindowText, SizeOf(WindowText)) > 0 then
  begin
    WindowTitle := String(WindowText);  // Convert char array to string
    
    // Check if window title contains any of our target strings
    for I := 0 to Titles.Count - 1 do
    begin
      // Use Pos function to check if target string is contained in window title
      if Pos(Titles[I], WindowTitle) > 0 then
      begin
        // Send WM_CLOSE message to close the window
        PostMessage(hWnd, WM_CLOSE, 0, 0);
        Break;  // Exit loop after finding first match
      end;
    end;
  end;
end;

// Main program execution begins here
begin
  // Close any existing PDF files that might be open in PDF viewers
  // This prevents file access conflicts when creating new PDFs with same names
  Titles := TStringList.Create;
  try
    // Define list of window title substrings to search for
    // Any window containing these strings will be closed
    // This will close Adobe and Foxit PDF reader & editor and many other PDF apps
    Titles.CommaText := '"HelloWorld-compressed.pdf", "HelloWorld-uncompressed.pdf", "Foxit"';

    // Enumerate all top-level windows and close matching ones
    // EnumWindows calls our callback function for each window
    EnumWindows(@EnumWindowsProc, LPARAM(Titles));
  finally
    Titles.Free;  // Clean up string list
  end;

  // Display program header
  WriteLn('=== HotPDF Compression Test ===');
  WriteLn('This demo creates two PDF files to demonstrate compression differences.');
  WriteLn('');

  // Create uncompressed PDF first
  // This version will be larger but faster to create
  CreatePDF('HelloWorld-uncompressed.pdf', False);

  // Create compressed PDF second
  // This version will be smaller but takes slightly longer to create
  CreatePDF('HelloWorld-compressed.pdf', True);

  // Display completion message
  WriteLn('');
  WriteLn('All PDF files created successfully!');
  WriteLn('Please check the files to compare compressed vs uncompressed versions.');
  WriteLn('You can examine file sizes to see the compression effect.');
  WriteLn('');
  WriteLn('Press Enter to exit...');
  ReadLn;  // Wait for user input before closing console

end.