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TextMarkup

Updated on Oct 6, 2025

Text Markup annotations appear as highlights, underlines, strikeouts, or jagged ("squiggly") underlines in the text of a document. When opened, they display a pop-up window containing the text of the associated note.

Text Markup Annotation

The TextMarkupAnnotation class is a derivative of the MarkupAnnotation (descendent of ContentAnnotation) and it exposes the following properties:

Property	Description
TextMarkupType	Gets the type of the annotation. The TextMarkupAnnotationType enum offers Highlight, StrikeOut, Underline, Squiggly options.
Opacity	Gets or sets the opacity of the annotation.
Contents	Gets or sets the text that shall be displayed for the annotation.
Color	Gets or sets the color of the annotation.
Content	Gets the source defining the visual content of the annotation. This content is with bigger priority compared to the annotation appearance characteristics and text properties and it is visualized by default when opening the exported document in some PDF viewer.

Depending on the TextMarkupAnnotationType the respective type of the TextMarkup annotation can be added to the PDF document using the below examples:

Highlight

Creating a Highlight Annotation

string sampleText = File.ReadAllText("dummyText.txt");

RadFixedDocument fixedDocument = new RadFixedDocument();
using (RadFixedDocumentEditor documentEditor = new RadFixedDocumentEditor(fixedDocument))
{
    documentEditor.InsertRun(sampleText);
}

TextSearch search = new TextSearch(fixedDocument);
IEnumerable<SearchResult> result = search.FindAll("amet", TextSearchOptions.Default);
foreach (SearchResult r in result)
{
    Rect highlightRectangle = r.GetWordBoundingRect();
    TextMarkupAnnotation annotation = r.GetResultPage().Annotations.AddHighlight(highlightRectangle);
    annotation.Color = new RgbColor(125, 255, 0, 0);

    annotation.RecalculateContent();
}

Create Highlight Annotation

Creating a Highlight Annotation with Appearance

private RadFixedDocument CreateTextMarkupAnnotation()
{
    string sampleText = File.ReadAllText("dummyText.txt");
    RadFixedDocument fixedDocument = new RadFixedDocument();
    using (RadFixedDocumentEditor documentEditor = new RadFixedDocumentEditor(fixedDocument))
    {
        documentEditor.InsertRun(sampleText);
    }
    TextMarkupAnnotation annotation = fixedDocument.Pages[0].Annotations.AddHighlight(new Rect(150, 150, 100, 40));

    FormSource simpleForm = new FormSource();
    CreateContentFormWithText(simpleForm, "Hover me!");
    annotation.Content.NormalContentSource = simpleForm;

    FormSource secondForm = new FormSource();
    CreateContentFormWithText(secondForm, "Hovered!");
    annotation.Content.MouseOverContentSource = secondForm;
    return fixedDocument;
}

private static void CreateContentFormWithText(FormSource normalForm, string text)
{
    Size s = new Size(100, 40);
    normalForm.Size = s;

    FixedContentEditor formEditor = new FixedContentEditor(normalForm);

    using (formEditor.SaveProperties())
    {
        formEditor.GraphicProperties.IsFilled = true;
        formEditor.GraphicProperties.IsStroked = true;
        formEditor.GraphicProperties.StrokeThickness = 1;
        formEditor.GraphicProperties.StrokeColor = new RgbColor(255, 0, 0);
        formEditor.GraphicProperties.FillColor = new RgbColor(175, 255, 255, 0);
        formEditor.GraphicProperties.StrokeDashArray = new double[] { 17, 4 };
        formEditor.DrawRectangle(new Rect(0, 0, s.Width, s.Height));
    }

    formEditor.TextProperties.FontSize = 16;
    formEditor.TextProperties.Font = FontsRepository.Courier;
    formEditor.Position.Translate(10, 10);
    formEditor.DrawText(text);
}

Create Highlight Annotation with Appearance

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

Underline

RadFixedDocument fixedDocument = new RadFixedDocument();
RadFixedPage page = fixedDocument.Pages.AddPage();
FixedContentEditor editor = new FixedContentEditor(page);
editor.Position.Translate(100, 100);
editor.DrawText("This is an underline.");

TextSearch search = new TextSearch(fixedDocument);
IEnumerable<SearchResult> underlineSearch = search.FindAll("underline", TextSearchOptions.Default);
Rect underlineRectangle = underlineSearch.First().GetWordBoundingRect();
TextMarkupAnnotation underlineAnnotation = page.Annotations.AddUnderline(underlineRectangle);
underlineAnnotation.Color = new RgbColor(255, 0, 255);
underlineAnnotation.Opacity = 0.90;
underlineAnnotation.RecalculateContent();

Create Underline Annotation

Squiggly

RadFixedDocument fixedDocument = new RadFixedDocument();
RadFixedPage page = fixedDocument.Pages.AddPage();
FixedContentEditor editor = new FixedContentEditor(page);
editor.Position.Translate(100, 100);
editor.DrawText("This is a squiggly line.");

TextSearch search = new TextSearch(fixedDocument);
IEnumerable<SearchResult> squigglySearch = search.FindAll("squiggly", TextSearchOptions.Default);
Rect squigglyRectangle = squigglySearch.First().GetWordBoundingRect();
TextMarkupAnnotation squigglyAnnotation = page.Annotations.AddSquiggly(squigglyRectangle);
squigglyAnnotation.Color = new RgbColor(255, 0, 0);
squigglyAnnotation.Opacity = 0.70;
squigglyAnnotation.RecalculateContent();

Create Squiggly Annotation

StrikeOut

RadFixedDocument fixedDocument = new RadFixedDocument();
RadFixedPage page = fixedDocument.Pages.AddPage();
FixedContentEditor editor = new FixedContentEditor(page);
editor.Position.Translate(100, 100);
editor.DrawText("This is a strikeout.");

TextSearch search = new TextSearch(fixedDocument);
IEnumerable<SearchResult> strikeoutSearch = search.FindAll("strikeout", TextSearchOptions.Default);
Rect strikeoutRectangle = strikeoutSearch.First().GetWordBoundingRect();
TextMarkupAnnotation strikeoutAnnotation = page.Annotations.AddStrikeout(strikeoutRectangle);
strikeoutAnnotation.Color = new RgbColor(0, 0, 255);
strikeoutAnnotation.Opacity = 0.90;
strikeoutAnnotation.RecalculateContent();

Create StrikeOut Annotation