Add lnk Annotation

Aspose.PDF for .NET is a powerful library that enables developers to perform various PDF operations. One such operation is adding Ink Annotation to PDF documents. In this article, we will provide a step-by-step guide to explain the C# source code for adding Ink Annotation using Aspose.PDF for .NET. Let’s get started!

Understanding the Ink Annotation Feature of Aspose.PDF for .NET

Before diving into the C# source code, let’s first understand what Ink Annotation is and its uses.

Ink Annotation is a way to draw freeform ink annotations on PDF documents. It allows you to create annotations with a stylus or a mouse. This feature is useful in situations where you need to draw diagrams, sketches, or other types of annotations.

Step 1: Creating a New Document

The first step in adding Ink Annotation to a PDF document is to create a new instance of the Document class. This is achieved using the following code snippet:

string dataDir = "YOUR DATA DIRECTORY";
Document doc = new Document();
Page pdfPage = doc.Pages.Add();

Here, we create a new instance of the Document class and add a new page to it.

Step 2: Creating Ink Annotation

The next step is to create an instance of the InkAnnotation class. This is done using the following code snippet:

System.Drawing.Rectangle drect = new System.Drawing.Rectangle();
drect.Height = (int)pdfPage.Rect.Height;
drect.Width = (int)pdfPage.Rect.Width;
drect.X = 0;
drect.Y = 0;
Aspose.Pdf.Rectangle arect = Aspose.Pdf.Rectangle.FromRect(drect);
IList<Point[]> inkList = new List<Point[]>();
Aspose.Pdf.Point[] arrpt = new Aspose.Pdf.Point[3];
inkList.Add(arrpt);
arrpt[0] = new Aspose.Pdf.Point(100, 800);
arrpt[1] = new Aspose.Pdf.Point(200, 800);
arrpt[2] = new Aspose.Pdf.Point(200, 700);
InkAnnotation ia = new InkAnnotation(pdfPage, arect, inkList);
ia.Title = "XXX";
ia.Color = Aspose.Pdf.Color.LightBlue; // (GetColorFromString(stroke.InkColor));
ia.CapStyle = CapStyle.Rounded;
Border border = new Border(ia);
border.Width = 25;
ia.Opacity = 0.5;
pdfPage.Annotations.Add(ia);

Here, we first create a rectangle using the System.Drawing.Rectangle class and convert it to Aspose.Pdf.Rectangle using the FromRect method. We then create an instance of the InkAnnotation class using the rectangle, a list of points, and the page where the annotation is added.

We then set various properties of the InkAnnotation, such as the title, color, cap style, border, and opacity. Finally, we add the annotation to the page using the Annotations.Add method.

Step 3: Saving the Document

The final step is to save the PDF document with the Ink Annotation added. This is achieved using the following code snippet:

dataDir = dataDir + "AddlnkAnnotation_out.pdf";
doc.Save(dataDir);

Here, we concatenate the output file name to the data directory and save the document using the Save method.

Example source code for Adding Ink Annotation using Aspose.PDF for .NET

// The path to the documents directory.
string dataDir = "YOUR DATA DIRECTORY";


Document doc = new Document();
Page pdfPage = doc.Pages.Add();
System.Drawing.Rectangle drect = new System.Drawing.Rectangle();
drect.Height = (int)pdfPage.Rect.Height;
drect.Width = (int)pdfPage.Rect.Width;
drect.X = 0;
drect.Y = 0;
Aspose.Pdf.Rectangle arect = Aspose.Pdf.Rectangle.FromRect(drect);
IList<Point[]> inkList = new List<Point[]>();
Aspose.Pdf.Point[] arrpt = new Aspose.Pdf.Point[3];
inkList.Add(arrpt);
arrpt[0] = new Aspose.Pdf.Point(100, 800);
arrpt[1] = new Aspose.Pdf.Point(200, 800);
arrpt[2] = new Aspose.Pdf.Point(200, 700);
InkAnnotation ia = new InkAnnotation(pdfPage, arect, inkList);
ia.Title = "XXX";
ia.Color = Aspose.Pdf.Color.LightBlue; // (GetColorFromString(stroke.InkColor));
ia.CapStyle = CapStyle.Rounded;
Border border = new Border(ia);
border.Width = 25;
ia.Opacity = 0.5;
pdfPage.Annotations.Add(ia);

dataDir = dataDir + "AddlnkAnnotation_out.pdf";
// Save output file
doc.Save(dataDir);

Conclusion

In this tutorial, we explored how to add Ink Annotations to a PDF document using Aspose.PDF for .NET. By following the step-by-step guide and C# source code provided, developers can easily implement Ink Annotation functionality in their PDF processing applications.

FAQ’s

Q: What is an Ink Annotation in a PDF document?

A: An Ink Annotation in a PDF document allows users to draw freeform ink annotations using a stylus or mouse. It is commonly used to add hand-drawn sketches, diagrams, or other freehand annotations to a PDF.

Q: Can I customize the appearance of the Ink Annotation?

A: Yes, Aspose.PDF for .NET provides various properties to customize the appearance of the Ink Annotation, such as color, opacity, cap style, border width, and more. Developers can adjust these properties to meet their specific requirements.

Q: Is it possible to add multiple Ink Annotations to a single PDF page?

A: Yes, you can add multiple Ink Annotations to a single PDF page using Aspose.PDF for .NET. Each Ink Annotation can have its own set of points and customized appearance.

Q: Can I add Ink Annotations to existing PDF documents?

A: Yes, Aspose.PDF for .NET allows you to add Ink Annotations to both newly created PDF documents and existing PDF files. You can open an existing PDF, add Ink Annotations, and save the updated document.

Q: What are some common use cases for Ink Annotations in PDF documents?

A: Ink Annotations are useful for a wide range of applications, including adding signatures or handwritten notes to PDF forms, annotating architectural blueprints or engineering drawings, and marking up documents for collaborative review.

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