Delphi HotPDF Component Hello World Sample

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: Use compression algorithms to optimise 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

HotPDF Component Delphi Hello World Sample

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 font for multilingual display support
Compression: Creating compressed PDF document

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 create a PDF document with FlateDecode compression

Font Handling Strategy

The program employs a sophisticated font selection strategy:

Arial Unicode MS: Used for most languages due to its broad character support
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

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

Getting Started

To run this example program:

Ensure HotPDF Component is properly installed in your Delphi IDE
Open the HelloWorld.dpr project file
Compile and run the program
The program will automatically create a PDF file with compression
Examine the generated files to see the multilingual text rendering

Source Code

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

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{************************************************************}

// HotPDF PDF Component

{************************************************************}

// 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 compressed PDF file with multilingual "Hello World" text

// Parameters:

// FileName: Output PDF file name

procedure CreatePDF(const FileName: string);

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

// Enable FlateDecode compression

HotPDF.Compression := cmFlateDecode; // Enable FlateDecode compression

WriteLn('Creating compressed PDF: ', FileName);

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

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;

// 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;

// 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.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 HelloWorld Demo ===');

WriteLn('This demo creates a compressed PDF file with multilingual text.');

WriteLn('');

// Create compressed PDF

CreatePDF('HelloWorld.pdf');

// Display completion message

WriteLn('');

WriteLn('PDF file created successfully!');

WriteLn('The PDF file uses FlateDecode compression for optimal file size.');

WriteLn('');

WriteLn('Press Enter to exit...');

ReadLn; // Wait for user input before closing console

end.