Using PdfSharp for Processing PDF from Native C++ : Hello World Sample

The whole package of PdfSharp comes with lots of sample applications, one of them is the obligatory hello world sample which shows how to create a PDF document with one page and the text “Hello, World!” written in its center.

You can see the resulting PDF as shown below.

The following is the original C# console application of Hello World. The C# source code was released under MIT and it was written by Thomas Hövel.

using System.Diagnostics;
using PdfSharp.Drawing;
using PdfSharp.Pdf;

namespace HelloWorld
{
    // This sample is the obligatory Hello World program.
    class Program
    {
        static void Main()
        {
            // Create a new PDF document.
            var document = new PdfDocument();
            document.Info.Title = "Created with PDFsharp";

            // Create an empty page in this document.
            var page = document.AddPage();

            // Get an XGraphics object for drawing on this page.
            var gfx = XGraphics.FromPdfPage(page);

            // Draw two lines with a red default pen.
            var width = page.Width;
            var height = page.Height;
            gfx.DrawLine(XPens.Red, 0, 0, width, height);
            gfx.DrawLine(XPens.Red, width, 0, 0, height);

            // Draw a circle with a red pen which is 1.5 point thick.
            var r = width / 5;
            gfx.DrawEllipse(new XPen(XColors.Red, 1.5), XBrushes.White, new XRect(width / 2 - r, height / 2 - r, 2 * r, 2 * r));

            // Create a font.
            var font = new XFont("Times New Roman", 20, XFontStyle.BoldItalic);

            // Draw the text.
            gfx.DrawString("Hello, PDFsharp!", font, XBrushes.Black,
                new XRect(0, 0, page.Width, page.Height), XStringFormats.Center);

            // Save the document...
            const string filename = "HelloWorld_tempfile.pdf";
            document.Save(filename);

            // ...and start a viewer.
            Process.Start(filename);
        }
    }
}

In the previous article, we talked about how to use xInterop C++ .NET Bridge with Native C++ to .NET Bridge to generate the native C++ bridge DLL for PDFsharp .NET library assembly. In this Hello World example, we will need to use the native C++ bridge DLL PdbSharpgidBridge.DLL.

The following is the complete source code of the example.

// ----------------------------------------------------------------------------
// <copyright file="TestApp.cpp" company="xInterop Software, LLC">
// Copyright (c) 2016 xInterop Software, LLC. All rights reserved.
// http://www.xinterop.com
// </copyright>
//
// NOTICE:  All information contained herein is, and remains the property of 
// xInterop Software, LLC, if any. The intellectual and technical concepts 
// contained herein are proprietary to xInterop Software, LLC and may be 
// covered by U.S. and Foreign Patents, patents in process, and are protected 
// by trade secret or copyright law. Dissemination of this information or 
// reproduction of this material is strictly forbidden unless prior written 
// permission is obtained from xInterop Software, LLC. 
//
// This copyright header must be kept intact without any change under any circumstances.
//
// The source code of this file can NOT be re-distributed to any third parties
// unless certain OEM license has been arranged and written permission has been
// authorized by xInterop Software, LLC.
//
// ----------------------------------------------------------------------------

#include "stdafx.h"
#include <Ole2.h>

#include "../Native/Include/PdfSharpgdiBridge.h"

#ifdef _WIN64
#pragma comment(lib, "../Native/Lib/x64/PdfSharpgdiBridge.lib")
#else
#pragma comment(lib, "../Native/Lib/win32/PdfSharpgdiBridge.lib")
#endif


using namespace xinterop;
using namespace System::Diagnostics;
using namespace PdfSharp::Pdf;
using namespace PdfSharp::Drawing;


int _tmain(int argc, _TCHAR* argv[])
{
    ///////////////////////////////////////////////////////////////////////////////////////////////
    //
    // Notes:
    //
    // This file was created when "Load .NET bridge assembly automatically" option was turned on.
    //
    // The C# bridge assembly shall be loaded and initialized automatically when any c++     
    // class of the C++ bridge DLL is accessed.
    //
    // The C# bridge assembly can also be loaded and initialized by calling xiInitializeBridgeAssembly.
    //
    ///////////////////////////////////////////////////////////////////////////////////////////////

    CoInitializeEx(0, COINIT_APARTMENTTHREADED);

    ///////////////////////////////////////////////////////////////////////////////////////////////
    // Add your code here.
    ///////////////////////////////////////////////////////////////////////////////////////////////

    // Create a new PdfDocument instance.
    PdfDocument document;

    document.Info->Title = _T("Created with PDFsharp");

    // Create an empty page in this document.
    auto page = document.AddPage();

    // Get an XGraphics object for drawing on this page.
    auto gfx = XGraphics::FromPdfPage(page.get());

    // Draw two lines with a red default pen.
    auto width = page->Width;
    auto height = page->Height;
    gfx->DrawLine(XPens::get_Red().get(), 0, 0, width->Value, height->Value);
    gfx->DrawLine(XPens::get_Red().get(), width->Value, 0, 0, height->Value);

    // Draw a circle with a red pen which is 1.5 point thick.
    auto r = width->Value / 5;
    XRect rectForCircle(width->Value / 2 - r, height->Value / 2 - r, 2 * r, 2 * r);
    XPen pen(XColors::get_Red().get(), 1.5);
    gfx->DrawEllipse(&pen, XBrushes::get_White().get(), &rectForCircle);

    // Create a font.
    XFont font(_T("Times New Roman"), 20, XFontStyle::BoldItalic);

    // Draw the text.
    XRect rectForText(0, 0, page->Width->Value, page->Height->Value);
    gfx->DrawString(_T("Hello, PDFsharp!"), &font, XBrushes::get_Black().get(), &rectForText, XStringFormats::get_Center().get());

    // Save the document...    
    auto filename = _T("HelloWorld_tempfile.pdf");
    document.Save(filename);

    // ...and start a viewer.
    Process::Start(filename);

    ///////////////////////////////////////////////////////////////////////////////////////////////
    // End of your code.
    ///////////////////////////////////////////////////////////////////////////////////////////////

    CoUninitialize();

    exit(0);

    return 0;
}

The C++ code is very similar to the C# counterpart since we can simulate the C# property in the C++ code. Let’s go over the important steps before we can start calling the functions.

1. Include the header file for the native C++ Bridge DLL.

2. Reference the native C++ Bridge lib files.

3. Define all the required namespace inclusion.

There are a few things worth mentioning in the C++ code.

1. Define an instance of the C++ bridge class on the stack.

In the preceding screen-shot, the variable of document is created on the stack. It is simple, you certainly can create a pointer of an instance of PdfDocument by calling â€œnewâ€ and then release it later on.

2. Using properties.