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Block

Updated on Jun 3, 2026

The Block class arranges the elements added to it in a flow-like manner. You can use it for measuring, drawing, and splitting of FixedContentElements.

Add and Modify Content

The most common usage of Block is to draw flowing content. Similarly to FixedContentEditor, a block can contain images, graphics, or text. The same Block instance can only be drawn once.

Inserting Text

Insert TextFragments with one of the overloads of the Insert() method. Example 1 shows all the overloads which allow specifying the styles and font family.

Example 1: Insert text

Telerik.Windows.Documents.Fixed.Model.Editing.Block block = new Block();
block.InsertText("Text");
#if NET8_0_WINDOWS
//.NET Framework
block.InsertText(new System.Windows.Media.FontFamily("Arial"), "Text");
block.InsertText(new System.Windows.Media.FontFamily("Arial"), System.Windows.FontStyles.Italic,
    System.Windows.FontWeights.Bold, "Text");
#else
//.NET Standard
//block.InsertText(new Telerik.Documents.Core.Fonts.FontFamily("Arial"), "Text");  
//block.InsertText(new Telerik.Documents.Core.Fonts.FontFamily("Arial"), Telerik.Documents.Core.Fonts.FontStyles.Italic, Telerik.Documents.Core.Fonts.FontWeights.Bold, "Text"); 
#endif

The '\r' and '\n' characters do not have the usual meaning of "go to next line" when inserted into a PDF document, and you cannot insert text containing these characters to produce multiline text. Instead, insert a line break.

In .NET Standard/.NET (Target OS: None) environments, fonts beyond the 14 standard ones require a FontsProvider implementation to be resolved correctly.

Inserting Line Break

Inserting a line break results in the next element starting on a new line. Use the InsertLineBreak() method as shown in Example 2.

Example 2: Break the line

block.InsertLineBreak();

Inserting Image

Block provides the following methods for inserting images:

block.InsertImage(imageSource);
block.InsertImage(stream);
block.InsertImage(imageSource, size);
block.InsertImage(stream, size);
block.InsertImage(imageSource, width, height);
block.InsertImage(stream, width, height);

Example 3: Inserting an image

string imageFilePath = "sample.jpg";
FileStream fileStream = new FileStream(imageFilePath, FileMode.Open);
Telerik.Windows.Documents.Fixed.Model.Resources.ImageSource imageSrc =
    new Telerik.Windows.Documents.Fixed.Model.Resources.ImageSource(fileStream);

block.InsertImage(imageSrc, 300, 200);

Information on images in the context of the library is available in the ImageSource and Image articles.

Inserting Geometries

Geometries allow you to describe 2D shapes in a document. The following methods can be used to insert different geometries:

block.InsertCircle(center, radius);
block.InsertEllipse(center, radiusX, radiusY);
block.InsertLine(point1, point2);
block.InsertPath(geometry);
block.InsertRectangle(rectangle);

Example 4: Inserting a geometry

Telerik.Windows.Documents.Fixed.Model.Graphics.RectangleGeometry rectangleGeometry =
    new Telerik.Windows.Documents.Fixed.Model.Graphics.RectangleGeometry();

#if NET8_0_WINDOWS //.NET Framework
rectangleGeometry.Rect = new System.Windows.Rect(10, 10, 400, 300); 
block.InsertRectangle(new System.Windows.Rect(10, 10, 200, 150)); 
#else //.NET Standard
//rectangleGeometry.Rect = new Telerik.Documents.Primitives.Rect(10, 5, 400, 300); 
//block.InsertRectangle(new Telerik.Documents.Primitives.Rect(20, 30, 200, 150)); 
#endif
block.InsertPath(rectangleGeometry);

Inserting Form-XObject Elements

The Form (also known as Form-XObject) is an object that can contain PDF content and can be shared among the document. The Block class exposes the InsertForm() method that allows you to insert a FormSource object in the document.

Example 5: Insert a form


FormSource simpleForm = new FormSource();
#if NET8_0_WINDOWS
simpleForm.Size = new System.Windows.Size(310, 250); // .NET Framework 
#else
//simpleForm.Size = new Telerik.Documents.Primitives.Size(310, 250); // .NET Standard 
#endif

FixedContentEditor formEditor = new FixedContentEditor(simpleForm);
formEditor.DrawText("Sample text.");

block.InsertForm(simpleForm);

There are two more overloads of InsertForm() that allow you to pass the size that should be used for the form.

For more information on how to create a form, see the Form and FormSource articles.

Inserting Link Annotation

The following example shows how to insert a link inside the text:

Example: Insert a text link

Block block = new Block();
block.InsertHyperlinkStart(new Uri("https://docs.telerik.com/devtools/document-processing/libraries/radpdfprocessing/getting-started"));
block.InsertText("text");
block.InsertHyperlinkEnd();

Changing Current Styles

The Block class has properties and methods that affect how it is rendered:

SpacingBefore: Represents the spacing before.
SpacingAfter: Represents the spacing after.
LineSpacing: The spacing between the lines.
LineSpacingType: Specifies how to interpret the line spacing.
FirstLineIndent: The indent for the first line.
LeftIndent: The left indent.
RightIndent: The right indent.
BackgroundColor: The background color.
HorizontalAlignment: The horizontal alignment of the content.
VerticalAlignment: The vertical alignment of the content.
Bullet: The element that is rendered as the Block list bullet.
IndentAfterBullet: The indent size after the bullet element.
TextProperties and GraphicProperties: Responsible for text and graphic properties. For more information, see the Text and Graphic Properties article.
SaveTextProperties(): Saves the TextProperties. It returns an IDisposable object which when disposed calls RestoreTextProperties() and can be used in a using statement.
RestoreTextProperties(): Restores the TextProperties to their previous state.
SaveGraphicProperties(): Saves the GraphicProperties. It returns an IDisposable object which when disposed calls RestoreGraphicProperties() and can be used in a using statement.
RestoreGraphicProperties(): Restores the GraphicProperties to their previous state.
SaveProperties(): Saves both text and graphic properties. It returns an IDisposable object which when disposed calls RestoreProperties() and can be used in a using statement.
RestoreProperties(): Restores both text and graphic properties.
SetBullet(List list, int listLevel): This method helps you set bullet-related properties respecting the numbering and the formatting of some List class instance. More information about lists is available in the List article.
Clear(): Clears all elements in the block.

Example 6: Change Block properties

RadFixedDocument radFixedDocument = new RadFixedDocument();
RadFixedPage page = radFixedDocument.Pages.AddPage();

Block block = new Block();
block.GraphicProperties.FillColor = new RgbColor(100, 0, 0, 0);
block.SpacingBefore = 10;
block.SpacingAfter = 5;
block.LineSpacingType = HeightType.Exact;
block.LineSpacing = 15;
block.FirstLineIndent = 0;
block.LeftIndent = 0;
block.RightIndent = 0;
block.BackgroundColor = new RgbColor(100, 255, 0, 0);
block.HorizontalAlignment = Telerik.Windows.Documents.Fixed.Model.Editing.Flow.HorizontalAlignment.Left;
block.VerticalAlignment = Telerik.Windows.Documents.Fixed.Model.Editing.Flow.VerticalAlignment.Top;
block.InsertText("block content");

TextFragment bulletTextFragment = new TextFragment();
bulletTextFragment.Text = "•";
block.Bullet = bulletTextFragment;
block.IndentAfterBullet = 15;

var editor = new FixedContentEditor(page);
editor.Position.Translate(50, 50);
editor.DrawBlock(block);

Block Properties Result

Drawing a Block

A Block can be drawn to the content using the Draw() method. The method accepts as a parameter a Rectangle, specifying the desired size and position relative to the editor of the element.

Example 7: Draw block

Rect boundingRect = new Rect(0, 0, 200, 300);
block.Draw(editor, boundingRect);

Every block can be drawn only once. Otherwise, an exception is thrown.

Measuring Block Size

Measuring a Block can be achieved with one of the two overloads of the Measure() method.

Invoking the method without a parameter returns the desired size of the block elements and sets it as the block DesiredSize property. The method is handy when you want to determine what size the Block needs depending on its content.

Example 8 creates a Block with text, measures the text, and sets the block size to match the content size.

Block block = new Block();
block.BackgroundColor = new RgbColor(255, 255, 0, 0);
block.InsertText("Telerik Document Processing Libraries.");

// The size of the block content (DesiredSize)
Size desiredBlockContentSize = block.Measure(); // Width: 232.653, Height: 15.306

fixedContentEditor.DrawBlock(block); // If the block size (ActualSize) is not specified, it will automatically be assigned the content size (DesiredSize)

// Draw the block with Size equal to the size of the content
fixedContentEditor.DrawBlock(block, desiredBlockContentSize); // The block size (ActualSize) can also be explicitly set to the content size (DesiredSize) when drawing the block

Example 8 Result

Rad Pdf Processing Measuring Block 01

The second overload accepts an available Size. Calling it measures the block content as if the Block was in that specific size. Additionally, it sets the PendingElements property with a collection of the elements that could not fit in the available size.

Example 9 creates a Block with text and draws it with a specific size using the FixedContentEditor. The block content auto-fits to the dimensions of the Block. The size of the auto-fitted content can then be measured.

Block block = new Block();
block.BackgroundColor = new RgbColor(255, 255, 0, 0);
block.InsertText("Telerik Document Processing Libraries.");

// Draw with a specific block size (ActualSize), ignoring the content size (DesiredSize)
Size specificBlockSize = new Size(100, 100);
fixedContentEditor.DrawBlock(block, specificBlockSize);

// The size of the block content (DesiredSize) autofitted in the specified dimensions
CancellationTokenSource cancellationTokenSource = new(TimeSpan.FromSeconds(10));
CancellationToken cancellationToken = cancellationTokenSource.Token;
Size autoFittedBlockContentSize = block.Measure(specificBlockSize, cancellationToken); // Width: 65.946, Height: 61.226

Block helloBlock = new Block();
helloBlock.InsertText("Hello");
Size helloSize = helloBlock.Measure();

Block block = new Block();
block.InsertText("Hello RadPdfProcessing!");

CancellationTokenSource cancellationTokenSource = new(TimeSpan.FromSeconds(10));
CancellationToken cancellationToken = cancellationTokenSource.Token;

Size size = block.Measure(helloSize, cancellationToken);

Block secondBlock = block.Split();