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Home » Newsletter » December 2010

By V. Subhash

If you are familiar with XML and XSLT, then you also know that transformed XML documents can be displayed inside a web browser just like a web page.

Well, it does not stop with transformed XML. A lot of people have been asking us about exporting XML to PDF and other formats. And, here is our solution.

Our solution uses an old Delphi component called THTMLViewer. THTMLViewer is no longer under development by its original authors. The last update from them was for Delphi 2006. However, the authors had made the project open source. There is a Delphi 2009 update for the component from the good folks at www.songbeamer.com/delphi/.

Before you try our solution, you need to install the new THTMLViewer and then recompile eDocEngine's export interface component for THTMLViewer - TgtHtmlViewInterface. The test XML and XSL files used in our example code are named gnostice_nl.xsl and placed in the project folder. (You can use any XML and XSL file so long as the THTMLViewer can display it without problem.) Here are the steps for creating the Delphi application.

1. Open the IDE and create a VCL forms application project.
2. Drop the following components on the form.
   1. TButton
   2. TMemo
   3. THTMLViewer
   4. TgtPDFEngine
   5. TgtHtmlViewInterface
   

   Components for the XML-to-PDF Delphi Application

3. Add the following click-event handler for the button.

   procedure TForm1.Button1Click(Sender: TObject);
   var
      XMLDocument1:  TXMLDocument;
      XSLPageProducer1: TXSLPageProducer;
   begin
     XMLDocument1 :=  TXMLDocument.Create(self);
     XSLPageProducer1 := TXSLPageProducer.Create(self);
   
     try
       // Transform XML and place HTML in memo
       XMLDocument1.Active := False;
       XSLPageProducer1.FileName := 'Input_Docs\gnostice_nl.xsl';
       XMLDocument1.FileName := 'Input_Docs\gnostice_nl.xml';
       XSLPageProducer1.XMLData := XMLDocument1;
       XMLDocument1.Active := True;
       Memo1.Text := XSLPageProducer1.Content;
       XMLDocument1.Active := False;
   
       // Display HTML from memo
       HTMLViewer1.LoadFromString(Memo1.Text);
   
       // Export displayed HTML to PDF
       gtHtmlViewInterface1.Engine := gtPDFEngine1;
       gtPDFEngine1.Preferences.ShowSetupDialog := false;
       gtPDFEngine1.FileName := 'Output_Docs\gnostice_nl.pdf';
       gtHtmlViewInterface1.RenderDocument(HTMLViewer1);
     except on E: Exception do
       Memo1.Text := E.Message
     end;
   
   end;
   

4. Run the application.
5. Click the button - to transform the XML to HTML, display the HTML in the viewer, and finally to export the displayed contents of the viewer to PDF using eDocEngine.
   

   XML-to-PDF Delphi Application In Action

Here is the final output.

Downloads

• xml_to_pdf_using_delphi.zip - Delphi project to convert XML+XSL transformations to PDF using Gnostice eDocEngine and Pbear's THTMLViewer