DEV Community: Usman Aziz

PowerPoint Automation in .NET and Java Applications

Usman Aziz — Thu, 02 Sep 2021 06:22:24 +0000

PowerPoint automation has emerged as a powerful solution in various business use cases to generate or manipulate presentations. In this post, I am just listing a few useful articles that cover PowerPoint automation and provide basic as well as advanced knowledge of how to create or manipulate PowerPoint presentations using Java, C#, or VB.NET.

Cheers!

Excel Automation in Python, Java, C#, Node.js, PHP and Android

Usman Aziz — Wed, 23 Jun 2021 04:34:46 +0000

Excel automation has emerged as a powerful solution in various business use cases. Automated generation of data and Excel spreadsheets have been adopted in various domains. In this post, I am just listing a few useful blog posts that cover Excel automation and provide basic as well as advanced knowledge of how to create Excel files using popular programming languages such as Python, Java, C#, Node.js and PHP. Here we go:

Cheers!

Generate and read barcodes in C#, Java, PHP and Node.js

Usman Aziz — Wed, 26 May 2021 06:57:53 +0000

Barcodes have become essential part of various business domains. Almost every product these days contains a barcode that represents a particular information about that product. In this article, I am going to list some useful articles that provide code samples of how to generate or read barcodes in C#, Java, PHP, and Node.js. Hope it will help the concerned developers.

Cheers!

Convert PDF Documents to MS Word, Excel, and PowerPoint using C# or Java

Usman Aziz — Mon, 07 Sep 2020 16:44:08 +0000

As a file format enthusiast, I have seen various use cases where there is a need for PDF conversion to other formats such as DOCX, XLSX, PPTX and etc. programmatically. C# and Java being two of the most popular and widely adopted languages have been part of the popular search queries for PDF conversion. For the ease of other developers, I am listing down the articles that demonstrate how to convert PDF documents to other file formats using C# and Java code samples.

Java

C#.NET

Cheers!

Convert Word, Excel, PowerPoint and HTML Documents to PDF Programmatically

Usman Aziz — Tue, 04 Feb 2020 05:15:14 +0000

In this post, I am listing a few helpful articles for those who are looking for some easy ways to convert the popular document formats of Word, Excel, PowerPoint and HTML documents to PDF programmatically using C# or Java. I hope it helps C# and Java developers.

C#.NET

Java

ASP.NET MVC Spreadsheet Viewer - Spreadsheet File Viewer

Usman Aziz — Fri, 31 Jan 2020 13:36:07 +0000

If you are looking for a simple and easy to code ASP.NET MVC Spreadsheet File Viewer, please have a look at the following article. It is a comprehensive tutorial along with the source code on how to create a Spreadsheet File Viewer in ASP.NET MVC using C# within a few steps. Read the article and download the source code ASP.NET MVC Spreadsheet - An Excel Viewer

Document Viewer in ASP.NET Core MVC for 140+ Document Formats

Usman Aziz — Thu, 21 Nov 2019 07:38:59 +0000

The online document viewer applications have become popular after the grown usage of digital documents, especially in the content management systems. The reason behind this popularity is you can view a multitude of document formats without purchasing or installing dedicated software programs. Considering the importance of document viewers, I thought to write an article on how to create a universal document viewer application.

This document viewer will be an ASP.NET Core MVC application and it will target the .NET Core framework. For the document rendering at the backend, we’ll use GroupDocs.Viewer for .NET API – a powerful file viewer API which supports over 140 document types including PDF, Word, Excel, PowerPoint, Visio, CAD, Outlook, and many other popular formats.

Why .NET Core?

.NET Core is a valuable addition to the .NET ecosystem by Microsoft. It makes it possible to develop cross-platform applications without any additional efforts required by the developers. This is why I have selected .NET Core to be the targetted framework.

Steps to Create Document Viewer in ASP.NET Core

1. Create a new project in Visual Studio.

2. Select .NET Core from the project types and ASP.NET Core Web Application from templates.

3. Select Web Application (Model-View-Controller) and click Ok button.

4. Install GroupDocs.Viewer from NuGet.

5. Open Views/Home/Index.cshtml file and replace its content with the following:

@{
    ViewData["Title"] = "Home Page";
}
<script src="http://code.jquery.com/jquery-1.8.2.js"></script>
<script>
    function ViewDocument(file) {
        $("#loader").fadeIn();
        var data = { FileName: file };
        $.ajax({
            type: "POST",
            url: '/Home/OnPost',
            data: data,
            dataType: "text"
        }).done(function (data) {
            var folderName = file.replace(".", "_");
            $("#content").empty();
            for (var i = 1; i <= data; i++) {
                $("#content").append("<img src='Content/" + folderName + "/page-" + i + ".png'/>");
            }
            $("#loader").fadeOut();
        })
    }
</script>
<script type="text/javascript">
    $(window).load(function () {
        $("#loader").fadeOut(1000);
    });
</script>
<div class="row">
    <div class="col-md-3">
        <div class="sidenav">
            <div id="loader"></div>
            <h2 style="padding-left:15px">Files</h2>
            @if (ViewBag.lstFiles != null)
            {
                @foreach (string file in ViewBag.lstFiles)
                {
                    <a href="#" onclick="ViewDocument('@file')">@file</a>
                }
            }
        </div>
    </div>
    <div class="col-md-9">
        <h2>Preview</h2>
        <div id="content"></div>
    </div>
</div>

6. Open Controllers/HomeController.cs and replace the content of the class with the following code.

public class HomeController : Controller
{
    private readonly IHostingEnvironment _hostingEnvironment;
    private string projectRootPath;
    private string outputPath;
    private string storagePath;
    List<string> lstFiles; 

    public HomeController(IHostingEnvironment hostingEnvironment)
    {
        _hostingEnvironment = hostingEnvironment;
        projectRootPath = _hostingEnvironment.ContentRootPath;
        outputPath = Path.Combine(projectRootPath, "wwwroot/Content");
        storagePath = Path.Combine(projectRootPath, "storage");
        lstFiles = new List<string>(); 
    }

    public IActionResult Index()
    {
        var files = Directory.GetFiles(storagePath);
        foreach (var file in files)
        {
            lstFiles.Add(Path.GetFileName(file));
        }
        ViewBag.lstFiles = lstFiles; 
        return View();
    }
    [HttpPost]
    public IActionResult OnPost(string FileName)
    {
        int pageCount = 0;
        string imageFilesFolder = Path.Combine(outputPath, Path.GetFileName(FileName).Replace(".", "_"));
        if (!Directory.Exists(imageFilesFolder))
        {
            Directory.CreateDirectory(imageFilesFolder);
        }
        string imageFilesPath = Path.Combine(imageFilesFolder, "page-{0}.png");
        using (Viewer viewer = new Viewer(Path.Combine(storagePath, FileName)))
        {
      //Get document info
            ViewInfo info = viewer.GetViewInfo(ViewInfoOptions.ForPngView(false));
            pageCount = info.Pages.Count;
      //Set options and render document
            PngViewOptions options = new PngViewOptions(imageFilesPath);
            viewer.View(options);
        } 
        return new JsonResult(pageCount);
    } 

    [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
    public IActionResult Error()
    {
        return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
    }
}

7. Append the following styles in the wwwroot/css/site.css file.

.sidenav {
    width: 300px;
    position: fixed;
    z-index: 1;
    left: 0px;
    background: #eee;
    overflow-x: hidden;
    padding: 8px 0;
}
.sidenav a {
    padding: 6px 8px 6px 16px;
    text-decoration: none;
    font-size: 15px;
    color: #2196F3;
    display: block;
}
.sidenav a:hover {
        color: #064579;
    }
.main {
    margin-left: 140px; /* Same width as the sidebar + left position in px */
    font-size: 15px; /* Increased text to enable scrolling */
    padding: 0px 10px;
}
@media screen and (max-height: 450px) {
    .sidenav {
        padding-top: 15px;
    }
        .sidenav a {
            font-size: 20px;
        }
}
#loader {
    position: fixed;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    z-index: 9999;
    background: url('../../images/Loading.gif') 50% 50% no-repeat rgb(249,249,249);
}

8. Build the application and run in your favorite browser.

Download

The complete source code of the application is available here in the Download section.

Cheers!

C#: Extract Data from Database Files without SQL

Usman Aziz — Sun, 10 Nov 2019 10:32:26 +0000

The database is considered to be an integral part of most of the applications. Be it a desktop, web or mobile application, database plays a vital role in storing, accessing and manipulating the data. There are many database management systems that allow creating and managing databases for you.

However, there could be a scenario when you need a way to extract data from database files, i.e. .db file, without installing a database management system or writing the SQL queries. How would you parse the database file in such a case and get the data from it?

In this article, I am going to demonstrate how easily you can extract the data from the tables in an SQLite database without writing SQL queries. I am going to use GroupDocs.Parser for .NET API which supports extracting data from databases via ADO.NET.

Steps to Extract Data from Tables in SQLite Database (.db)

1. Create a new project in Visual Studio.

2. Install GroupDocs.Parser for .NET from NuGet.

3. Add the following namespaces.

using System;
using System.Collections.Generic;
using System.IO;
using GroupDocs.Parser.Data;
using GroupDocs.Parser.Options;

4. Prepare the connection string.

string connectionString = string.Format("Provider=System.Data.Sqlite;Data Source={0};Version=3;", "sqlite.db");

5. Load the database file in the Parser object.

using (Parser parser = new Parser(connectionString, new LoadOptions(FileFormat.Database)))
{
   // your code goes here
}

6. Get list of the tables in the database using Parser.GetToc method.

// Get a list of tables
IEnumerable<TocItem> toc = parser.GetToc();

7. Iterate over the tables and extract data.

// Iterate over tables
foreach (TocItem i in toc)
{
    // Print the table name
    Console.WriteLine(i.Text);
    // Extract a table content as a text
    using (TextReader reader = parser.GetText(i.PageIndex.Value))
    {
          Console.WriteLine(reader.ReadToEnd());
    }
}

Complete Code

string connectionString = string.Format("Provider=System.Data.Sqlite;Data Source={0};Version=3;", "sqlite.db");
// Create an instance of Parser class to extract tables from the database.
// Connection string is passed as first parameter and LoadOptions is set to Database file format.
using (Parser parser = new Parser(connectionString, new LoadOptions(FileFormat.Database)))
{
    // Get a list of tables
    IEnumerable<TocItem> toc = parser.GetToc();
    // Iterate over tables
    foreach (TocItem i in toc)
    {
        // Print the table name
        Console.WriteLine(i.Text);
        // Extract a table content as a text
        using (TextReader reader = parser.GetText(i.PageIndex.Value))
        {
            Console.WriteLine(reader.ReadToEnd());
        }
    }
}

Output

Cheers!

Prevent watermark tampering in Word Documents using C#

Usman Aziz — Wed, 06 Nov 2019 05:57:07 +0000

Watermarking is a famous way of adding labels to the documents that may indicate the state of the document such as draft, confidential, etc. It can be used to add a company’s logo behind the text of the document to avoid the ownership dispute. In some cases, people add watermarks to the documents to protect the content. But, are you sure that the content is protected and no one can remove those watermarks? There is no guarantee because various third-party tools are available that can wipe out the watermarks from the documents.

In such scenarios, you need some way to lock the watermarks to restrict the editing. In this article, I’ll show you how to protect your Word documents and prevent the editing of the watermarks programmatically in C# using GroupDocs.Watermark for .NET which is a document watermarking API.

Locking Watermark in Word Document

The above-mentioned API provides 5 variants of locking Word document when adding watermark.

Allowing Revisions Only

In this case, the user will only be able to add revision marks to the Word document. The content of the document as well as the watermark will be read-only.

Allowing Comments Only

If this type of restriction is applied then the user will only be able to modify the comments in the document.

Allowing Form Fields Only

With this option, the document is split into one-page sections and a locked section with the watermark is added between each two adjacent document sections.

Read Only with Editable Content

In this case, the document is marked as read-only but all the content except the watermark is marked as editable.

Completely Read Only

In this case, the entire document is marked as read-only and nothing can be edited.

Source Code

The following code sample shows how to impose the above-mentioned restrictions on a Word document when adding the watermark.

WordProcessingLoadOptions loadOptions = new WordProcessingLoadOptions();
using (Watermarker watermarker = new Watermarker("document.docx", loadOptions))
{
    TextWatermark watermark = new TextWatermark("Watermark text", new Font("Arial", 19));
    watermark.ForegroundColor = Color.Red;

    WordProcessingWatermarkPagesOptions options = new WordProcessingWatermarkPagesOptions();
    options.IsLocked = true;
    options.LockType = WordProcessingLockType.AllowOnlyComments;
    /* 
    options.LockType = WordProcessingLockType.AllowOnlyRevisions;
    options.LockType = WordProcessingLockType.AllowOnlyFormFields;
    options.LockType = WordProcessingLockType.ReadOnlyWithEditableContent;
    options.LockType = WordProcessingLockType.ReadOnly; 
    */

    // To protect with password
    //options.Password = "7654321";

    watermarker.Add(watermark, options);
    watermarker.Save("document_watermarked.docx");
}

Cheers!

Extract Data from Invoices or Receipts in C#

Usman Aziz — Thu, 24 Oct 2019 16:34:53 +0000

Invoices and receipts are the documents that are used to record the transactions in a particular format when buying or selling of the services or goods is involved. Things have gone digital and with the popularity of online shopping, digital invoices are widely used. Processing a number of digital invoices and extracting the information manually is a complex as well as time taking process. Thus, you need a faster yet efficient way for such a case. So in this article, I am going to show you how to extract data from a PDF invoice or receipt programmatically in C#.

Workflow for Extracting Data from a PDF Invoice

The following is the workflow of how to extract the data from a PDF invoice using GroupDocs.Parser for .NET API.

Create table parameters for extracting data from the tables.
Create template items for extracting data from fields.
Parse the invoice according to the given template.
Extract the data.

The Invoice

The following is the screenshot of a sample PDF invoice that I’ll use for extracting the data. You can download this invoice from here.

The Code

Create the template for the given invoice (read more about templates).

// Create detector parameters for "Details" table
TemplateTableParameters detailsTableParameters = new TemplateTableParameters(new Rectangle(new Point(35, 320), new Size(530, 55)), null);

// Create detector parameters for "Summary" table
TemplateTableParameters summaryTableParameters = new TemplateTableParameters(new Rectangle(new Point(330, 385), new Size(220, 65)), null);

// Create a collection of template items
TemplateItem[] templateItems = new TemplateItem[]
{
    new TemplateField(new TemplateFixedPosition(new Rectangle(new Point(35, 135), new Size(100, 10))), "FromCompany"),
    new TemplateField(new TemplateFixedPosition(new Rectangle(new Point(35, 150), new Size(100, 35))), "FromAddress"),
    new TemplateField(new TemplateFixedPosition(new Rectangle(new Point(35, 190), new Size(150, 2))), "FromEmail"),
    new TemplateField(new TemplateFixedPosition(new Rectangle(new Point(35, 250), new Size(100, 2))), "ToCompany"),
    new TemplateField(new TemplateFixedPosition(new Rectangle(new Point(35, 260), new Size(100, 15))), "ToAddress"),
    new TemplateField(new TemplateFixedPosition(new Rectangle(new Point(35, 290), new Size(150, 2))), "ToEmail"),

    new TemplateField(new TemplateRegexPosition("Invoice Number"), "InvoiceNumber"),
    new TemplateField(new TemplateLinkedPosition(
        "InvoiceNumber",
        new Size(200, 15),
        new TemplateLinkedPositionEdges(false, false, true, false)),
        "InvoiceNumberValue"),

    new TemplateField(new TemplateRegexPosition("Order Number"), "InvoiceOrder"),
    new TemplateField(new TemplateLinkedPosition(
        "InvoiceOrder",
        new Size(200, 15),
        new TemplateLinkedPositionEdges(false, false, true, false)),
        "InvoiceOrderValue"),

    new TemplateField(new TemplateRegexPosition("Invoice Date"), "InvoiceDate"),
    new TemplateField(new TemplateLinkedPosition(
        "InvoiceDate",
        new Size(200, 15),
        new TemplateLinkedPositionEdges(false, false, true, false)),
        "InvoiceDateValue"),

    new TemplateField(new TemplateRegexPosition("Due Date"), "DueDate"),
    new TemplateField(new TemplateLinkedPosition(
        "DueDate",
        new Size(200, 15),
        new TemplateLinkedPositionEdges(false, false, true, false)),
        "DueDateValue"),

    new TemplateField(new TemplateRegexPosition("Total Due"), "TotalDue"),
    new TemplateField(new TemplateLinkedPosition(
        "TotalDue",
        new Size(200, 15),
        new TemplateLinkedPositionEdges(false, false, true, false)),
        "TotalDueValue"),

    new TemplateTable(detailsTableParameters, "details", null),
    new TemplateTable(summaryTableParameters, "summary", null)
};

// Create a document template
Template template = new Template(templateItems);

Parse the invoice and extract data.

// Create an instance of Parser class
using (Parser parser = new Parser("invoice.pdf"))
{
    // Parse the document by the template
    DocumentData data = parser.ParseByTemplate(template);

    // Print all extracted data
    for (int i = 0; i < data.Count; i++)
    {
        Console.Write(data[i].Name + ": ");
        // Check if the field is a table
        PageTableArea area = data[i].PageArea as PageTableArea;
        if (area == null)
        {
            PageArea pageArea = data[i].PageArea;
            Console.WriteLine(pageArea.ToString());
        }
        else
        {
            // Iterate via table rows
            for (int row = 0; row < area.RowCount; row++)
            {
                // Iterate via table columns
                for (int column = 0; column < area.ColumnCount; column++)
                {
                    // Get the cell value
                    PageTextArea cellValue = area[row, column].PageArea as PageTextArea;

                    // Print the space between columns
                    if (column > 0)
                    {
                        Console.Write("\t");
                    }

                    // Print the cell value
                    Console.Write(cellValue == null ? "" : cellValue.Text);
                }

                // Print new line
                Console.WriteLine();
            }
        }
    }
}

The Output

Cheers!

Count Words and Occurrences of Each Word in a Document using C#

Usman Aziz — Fri, 18 Oct 2019 06:23:05 +0000

Repetition of data can diminish the worth of the content. Working as a writer, you must follow DRY (don’t repeat yourself) principle. The statistics such as word count or the number of occurrences of each word can let you analyze the content but it’s hard to do it manually for multiple documents. So in this article, I’ll demonstrate how to programmatically count words and the number of occurrences of each word in PDF, Word, Excel, PowerPoint, Ebook, Markup, and Email document formats using C#. For extracting text from documents, I’ll be using GroupDocs.Parser for .NET which is a powerful document parsing API.

Steps to count words and their occurrences in C

1. Create a new project.

2. Install GroupDocs.Parser for .NET using NuGet Package Manager.

3. Add the following namespaces.

using GroupDocs.Parser;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

4. Create an instance of the Parser class and load the document.

using (Parser parser = new Parser("sample.pdf"))
{
  // your code goes here.
}

5. Extract the text from the document into a TextReader object using Parser.GetText() method.

using (TextReader reader = parser.GetText())
{

}

6. Split up the text into words, save them into a string array and perform word count.

Dictionary<string, int> stats = new Dictionary<string, int>();
string text = reader.ReadToEnd();
char[] chars = { ' ', '.', ',', ';', ':', '?', '\n', '\r' };
// split words
string[] words = text.Split(chars);
int minWordLength = 2;// to count words having more than 2  characters

// iterate over the word collection to count occurrences
foreach (string word in words)
{
    string w = word.Trim().ToLower();
    if (w.Length > minWordLength)
    {
        if (!stats.ContainsKey(w))
        {
            // add new word to collection
            stats.Add(w, 1);
        }
        else
        {
            // update word occurrence count
            stats[w] += 1;
        }
    }
}

7. Order the words by their occurrence count and display the results.

// order the list by word count
var orderedStats = stats.OrderByDescending(x => x.Value);
// print total word count
Console.WriteLine("Total word count: {0}", stats.Count);
// print occurrence of each word
foreach (var pair in orderedStats)
{
    Console.WriteLine("Total occurrences of {0}: {1}", pair.Key, pair.Value);
}

Complete Code

using (Parser parser = new Parser("sample.pdf"))
{                
    // Extract a text into the reader
    using (TextReader reader = parser.GetText())
    {
        Dictionary<string, int> stats = new Dictionary<string, int>();
        string text = reader.ReadToEnd();
        char[] chars = { ' ', '.', ',', ';', ':', '?', '\n', '\r' };
        // split words
        string[] words = text.Split(chars);
        int minWordLength = 2;// to count words having more than 2 characters

        // iterate over the word collection to count occurrences
        foreach (string word in words)
        {
            string w = word.Trim().ToLower();
            if (w.Length > minWordLength)
            {
                if (!stats.ContainsKey(w))
                {
                    // add new word to collection
                    stats.Add(w, 1);
                }
                else
                {
                    // update word occurrence count
                    stats[w] += 1;
                }
            }
        }

        // order the collection by word count
        var orderedStats = stats.OrderByDescending(x => x.Value);
        // print total word count
        Console.WriteLine("Total word count: {0}", stats.Count);
        // print occurrence of each word
        foreach (var pair in orderedStats)
        {
            Console.WriteLine("Total occurrences of {0}: {1}", pair.Key, pair.Value);
        }
    }
}

Results

Find and Remove Watermarks from Documents in Java

Usman Aziz — Fri, 11 Oct 2019 06:04:43 +0000

This article is useful for the Java developers who are looking for a way to find and remove text or image watermarks from PDF, Word, Excel, PowerPoint, Visio and Email documents.

GroupDocs.Watermark for Java API supports adding text and image watermarks to a wide range of document formats. In addition, it also has the ability to find and remove watermarks from the documents. The API also finds the watermark objects that are added using the third-party tools. So let me demonstrate how you can remove the watermark from a document in a few steps in Java.

Before we begin, have a look at the following PDF document which contains a text as well as an image watermark. We’ll use this document and remove the watermarks from it.

Steps to remove watermarks from a document

1. Create a new project.

2. Add the following imports.

 import com.groupdocs.watermark.Document; 
 import com.groupdocs.watermark.ImageDctHashSearchCriteria;
 import com.groupdocs.watermark.ImageSearchCriteria; 
 import com.groupdocs.watermark.PossibleWatermarkCollection;
 import com.groupdocs.watermark.SearchCriteria;
 import com.groupdocs.watermark.TextSearchCriteria;

3. Create an instance of Document class and load the source document.

 Document doc =Document.load("watermarked.pdf");

4. Find the watermarks based on search criteria using findWatermarks method (if you don’t pass any searching criteria, findWatermark will return all the possible watermark objects).

 // configure the search criteria for image watermark
 ImageSearchCriteria imageSearchCriteria =newImageDctHashSearchCriteria("watermark.png");
 // configure the search criteria for text watermark
 TextSearchCriteria textSearchCriteria =newTextSearchCriteria("CONFIDENTIAL");
 // combine the search criteria
 SearchCriteria combinedSearchCriteria = imageSearchCriteria.or(textSearchCriteria);
 // find possible watermarks
 PossibleWatermarkCollection possibleWatermarks = doc.findWatermarks(combinedSearchCriteria);

5. Iterate over the watermark collection and remove watermarks using removeAt method.

 // iterate through the collection and remove watermarks
 while(possibleWatermarks.getCount()&gt;0)
 {
 if (possibleWatermarks.get_Item(0).getImageData() !=null)
    {
        possibleWatermarks.removeAt(0);
 System.out.println("removed image watermark.");
    }
 else
    {
    possibleWatermarks.removeAt(0);
System.out.println("removed text watermark.");
    }
 }

6. Save the resultant document using save method.

 doc.save("without_watermark.pdf");
 doc.close();

Complete Code

 Document doc =Document.load("watermarked.pdf");
 // configure the search criteria for image watermark
 ImageSearchCriteria imageSearchCriteria =newImageDctHashSearchCriteria("watermark.png");
 // configure the search criteria for text watermark
 TextSearchCriteria textSearchCriteria =newTextSearchCriteria("CONFIDENTIAL");
 // combine the search criteria
 SearchCriteria combinedSearchCriteria = imageSearchCriteria.or(textSearchCriteria);
 PossibleWatermarkCollection possibleWatermarks = doc.findWatermarks(combinedSearchCriteria);
 // iterate through the collection and remove watermarks
 while(possibleWatermarks.getCount()&gt;0)
 {
 if (possibleWatermarks.get_Item(0).getImageData() !=null)
    {
        possibleWatermarks.removeAt(0);
 System.out.println("removed image watermark.");
    }
 else
    {
        possibleWatermarks.removeAt(0);
 System.out.println("removed text watermark.");
    }
 }        
 doc.save("without_watermark.pdf");
 doc.close();

Results

The following is the screenshot of the resultant PDF document that we get after removing the watermarks.

DEV Community: Usman Aziz

PowerPoint Automation in .NET and Java Applications

Excel Automation in Python, Java, C#, Node.js, PHP and Android

Generate and read barcodes in C#, Java, PHP and Node.js

Convert PDF Documents to MS Word, Excel, and PowerPoint using C# or Java

Java

C#.NET

Convert Word, Excel, PowerPoint and HTML Documents to PDF Programmatically

C#.NET

Java

ASP.NET MVC Spreadsheet Viewer - Spreadsheet File Viewer

Document Viewer in ASP.NET Core MVC for 140+ Document Formats

Why .NET Core?

Steps to Create Document Viewer in ASP.NET Core

Download

See Also

C#: Extract Data from Database Files without SQL

Steps to Extract Data from Tables in SQLite Database (.db)

Complete Code

Output

Prevent watermark tampering in Word Documents using C#

Locking Watermark in Word Document

Allowing Revisions Only

Allowing Comments Only

Allowing Form Fields Only

Read Only with Editable Content

Completely Read Only

Source Code

Extract Data from Invoices or Receipts in C#

Workflow for Extracting Data from a PDF Invoice

The Invoice

The Code

The Output

Count Words and Occurrences of Each Word in a Document using C#

Steps to count words and their occurrences in C

Complete Code

Results

Find and Remove Watermarks from Documents in Java

Steps to remove watermarks from a document

Complete Code

Results