Adding text items to an Existing PDF w/ Telerik DocumentProcessing Library

Question

I want to open an existing PDF document and add different annotations to it. Namely bookmarks and some text I am using the Telerik Document Processing Library (dpl) v2019.3.1021.40

I am new to dpl , but I believe the RadFlowDocument is the way to go. I am having troubles creating the RadFlowDocument

         FlowProvider.PdfFormatProvider provider = new FlowProvider.PdfFormatProvider();
             using (Stream stream = File.OpenRead(sourceFile))
            {
   -->           RadFlowDocument flowDoc  = provider.Import(stream);


            }

The line indicated w/ the arrow give the error "Import Not Supported"

There is a telerik blog post here https://www.telerik.com/forums/radflowdocument-to-pdf-error It seems relevant, but not 100% sure. It cautions to be sure the providers are mated correctly, I believe they are in my example....

Again, ultimate goal is to open a PDF and add some stuff to it. I think the RadFlowDocument is the right direction. If there is a better solution, Im happy to hear that too.

Answer 1

I figured it out. The DPL is pretty good, but doc is still growing, hope this helps someone out...

This draws from a myriad of articles, I cant begin to cite them all.

There are 2 notions for working w/ PDFs in the DPL. FixedDocument takes pages. I think this is meant for sewing docs together. FlowDocument I believe lays things out like an HTML renderer would.

I am using Fixed, mainly b/c I can get that to work.

    using System;
    using System.IO;
    using System.Windows;  //nec for Size struct
    using System.Diagnostics; //nec for launching the pdf at the end 

    using Telerik.Windows.Documents.Fixed.Model;
    //if you have fixed and flow provider, you have to specify, so I make a shortcut
    using FixedProvider = Telerik.Windows.Documents.Fixed.FormatProviders.Pdf;
    using Telerik.Windows.Documents.Fixed.Model.Editing;

    using Microsoft.VisualStudio.TestTools.UnitTesting;


    namespace DocAggregator
    {
        [TestClass]
        public class UnitTest2
        {
            [TestMethod]
            public void EditNewFIle_SrcAsFixed_TrgAsFixed()
            {
                String dt = @"C:\USERS\greg\DESKTOP\DPL\";
                String sourceFile = dt + "output.pdf";

                //Open the sourceDoc so you can add stuff to it
                RadFixedDocument sourceDoc;

                //a provider parses the actual file into the model. 

                FixedProvider.PdfFormatProvider fixedProv = new FixedProvider.PdfFormatProvider();
                using (Stream stream = File.OpenRead(sourceFile))
                {
                    //'populate' the doc object from the file

                    //using the  FLOW classes, I get "Import  Not Supported". 
                    sourceDoc = fixedProv.Import(stream);
                }
                int pages = sourceDoc.Pages.Count;
                int pageCounter = 1;
                int xoffset = 150;
                int yoffset = 50;

                //editor is the thing that lets you add elements into the source doc
//Like the provider, the Editor needs to match the document class (Fixed or Flow)
                RadFixedDocumentEditor editor = new RadFixedDocumentEditor(sourceDoc);

                foreach (RadFixedPage page in sourceDoc.Pages)
                {
                    FixedContentEditor pEd = new FixedContentEditor(page);
                    Size ps = page.Size;

                    pEd.Position.Translate(ps.Width - xoffset, ps.Height - yoffset);

                    Block block = new Block();
                    block.HorizontalAlignment = Telerik.Windows.Documents.Fixed.Model.Editing.Flow.HorizontalAlignment.Center;
                    block.TextProperties.FontSize = 22;
                    block.InsertText(string.Format("Page {0} of {1} ", pageCounter, pages));
                    pEd.DrawBlock(block);
                    pageCounter++;
                }

                string exportFileName = "addedPageNums.pdf";

                if (File.Exists(exportFileName))
                {
                    File.Delete(exportFileName);
                }

                File.WriteAllBytes(exportFileName, fixedProv.Export(sourceDoc));
                //launch the app
                Process.Start(exportFileName);
            }

        }
    }