This tutorial guides how to add watermark in PDF with C# REST API. You will learn to automatically insert watermark in PDF with C# Low Code API using the .NET-based Cloud SDK. It shares details to customize the watermark format and placement on a particular page.
Prerequisite
- Create an account API credentials
- Download Aspose.PDF Cloud SDK for Dotnet to insert a watermark in a PDF file
- Setup C# project with the above SDK for working with text stamps
Steps to Add Watermark to PDF Document with C# RESTful Service
- Configure the PdfApi class object with API key and App SID
- Create a Stamp object and set its parameters
- Upload the target PDF file to the cloud storage for adding a watermark
- Call the PutPageAddStamp() method to insert the Stamp as a watermark
- Download the PDF file with a watermark on it
These steps describe how to add watermark in PDF online with C# REST Interface. Instantiate the PdfApi object, create a stamp object, and set its properties followed by uploading the PDF file to the Cloud. Call the PutPageAddStamp() to add the stamp text as a watermark and save the output PDF file with the watermark on the disk.
Code to Put Watermark on PDF with C# REST Interface
| using System; | |
| using System.IO; | |
| using Aspose.Pdf.Cloud.Sdk.Api; | |
| using Aspose.Pdf.Cloud.Sdk.Model; | |
| using System.Collections.Generic; | |
| namespace Aspose.PDF.Cloud.Examples.Kb | |
| { | |
| public class PdfTasks | |
| { | |
| public static void Bookmark() | |
| { | |
| PdfApi pdfApi = new PdfApi("API_KEY", "APP_SID"); // For adding watermarks | |
| String fileName = "input.pdf"; | |
| int pageNumber = 1; | |
| Stamp body = new Stamp(); | |
| body.Value = "Aspose.com"; | |
| body.Background = true; | |
| body.Type = StampType.Text; | |
| body.XIndent = 50; | |
| body.YIndent = 50; | |
| body.RotateAngle = 45; | |
| body.TextState = new TextState(FontSize: 100); | |
| body.Opacity = 0.10; | |
| try | |
| { | |
| // Upload the PDF file | |
| FilesUploadResult result = pdfApi.UploadFile(fileName, new MemoryStream(File.ReadAllBytes(fileName))); | |
| // Invoke Aspose.PDF Cloud SDK API to add text stamp to a pdf page | |
| AsposeResponse apiResponse = pdfApi.PutPageAddStamp(fileName, pageNumber, body); | |
| if (apiResponse.Status == "OK") | |
| { | |
| // Download created pdf file | |
| Stream storageRes = pdfApi.DownloadFile(fileName); | |
| FileStream fileStream = new FileStream("output.pdf", FileMode.Create, FileAccess.Write); | |
| storageRes.CopyTo(fileStream); | |
| } | |
| Console.WriteLine("Add Text Stamp (Watermark) to a PDF Page, Done!"); | |
| Console.ReadKey(); | |
| } | |
| catch (Exception ex) | |
| { | |
| System.Diagnostics.Debug.WriteLine("error:" + ex.Message + "\n" + ex.StackTrace); | |
| } | |
| } | |
| } | |
| } |
This code has demonstrated how to put watermark on PDF with C# .NET-based API. You may set various parameters for a watermark stamp such as text as Value, stamp type, background flag, indentation, rotation settings, opacity, zoom level, foreground color, and margins. This SDK also supports reading and deleting watermarks and other stamps on a PDF file.
This article has taught us how to add a watermark to PDF document with C# RESTful Service. If you want to insert an image in a PDF file, follow the article Insert Image into PDF with C# REST API.
