How to Achieve Underline Text in RadSyntaxEditor
Environment
| Product Version | Product | Author |
|---|---|---|
| 2020.3.1020 | RadSyntaxEditor for WinForms | Desislava Yordanova |
Description
RadSyntaxEditor works with the underlying document with the help of taggers. Taggers are used to identify spans of text and assign them a specific tag if they match a specific condition. Thus, you can color different words in the document.
This article demonstrates a sample approach how to underline some text along with applying a specific fore color to it.
Solution
It can be achieved by using a custom tagger to classify the desired words (e.g. "Telerik") and mark these words as specific. Since RadSyntaxEditor renders its elements on different layers based on the types of tags that are used, we will need a custom layer for the underline style.
public Form1()
{
InitializeComponent();
this.radSyntaxEditor1.TaggersRegistry.RegisterTagger(new TelerikTagger(this.radSyntaxEditor1.SyntaxEditorElement));
this.radSyntaxEditor1.SyntaxEditorElement.UILayersBuilder = new CustomUILayersBuilder();
this.radSyntaxEditor1.TextFormatDefinitions.AddLast(TelerikTagger.TelerikClassificationType,
new TextFormatDefinition(new SolidBrush(System.Drawing.Color.Red), null,
new UnderlineInfo(new SolidBrush(System.Drawing.Color.Green), UnderlineDecorations.Line),
new Telerik.WinForms.Controls.SyntaxEditor.UI.Pen(new SolidBrush(System.Drawing.Color.Green), 2)));
}
public class TelerikTagger : WordTaggerBase
{
public static readonly ClassificationType TelerikClassificationType = new ClassificationType("Telerik");
public static readonly Dictionary<string, ClassificationType> WordsToClassificationType = new Dictionary<string, ClassificationType>();
public TelerikTagger(RadSyntaxEditorElement editor) : base(editor)
{
WordsToClassificationType.Add("Telerik", TelerikClassificationType);
}
protected override Dictionary<string, ClassificationType> GetWordsToClassificationTypes()
{
return TelerikTagger.WordsToClassificationType;
}
}
public class CustomUILayersBuilder : Telerik.WinForms.Controls.SyntaxEditor.UI.Layers.UILayersBuilder
{
public override void BuildUILayers(UILayerStack uiLayers)
{
base.BuildUILayers(uiLayers);
uiLayers.AddLast(new MyTextUnderlineUILayer());
}
}
public class MyTextUnderlineUILayer : LineBasedUILayer<ClassificationTag>
{
public override string Name => "MyTextUnderlineUILayer";
protected override FrameworkElement GetLinePartUIElement(ClassificationTag tag,
Telerik.WinForms.SyntaxEditor.Core.Text.Span span,
UIUpdateContext updateContext)
{
if (tag.ClassificationType != TelerikTagger.TelerikClassificationType)
{
return null;
}
TextFormatDefinition textFormatting = updateContext.Editor.TextFormatDefinitions.
GetTextFormatDefinition(TelerikTagger.TelerikClassificationType);
Telerik.WinControls.SyntaxEditor.UI.Rect rect = updateContext.Editor.GetLinePartBoundingRectangle(span, true);
Rect underlineRect = new Rect
{
Y = rect.Height,
Width = rect.Width,
Height = updateContext.Editor.EditorFontSize / 16
};
FrameworkElement underline = null;
if (textFormatting.Underline != null)
{
underline = textFormatting.Underline.CreateUnderline(underlineRect);
}
return underline;
}
protected override void ResetPooledElementProperties(object element)
{
}
}
Sub New()
InitializeComponent()
Me.RadSyntaxEditor1.TaggersRegistry.RegisterTagger(New TelerikTagger(Me.RadSyntaxEditor1.SyntaxEditorElement))
Me.RadSyntaxEditor1.SyntaxEditorElement.UILayersBuilder = New CustomUILayersBuilder()
Me.RadSyntaxEditor1.TextFormatDefinitions.AddLast(TelerikTagger.TelerikClassificationType,
New TextFormatDefinition(New SolidBrush(System.Drawing.Color.Red),
Nothing, New UnderlineInfo(New SolidBrush(System.Drawing.Color.Green),
UnderlineDecorations.Line), New Telerik.WinForms.Controls.SyntaxEditor.UI.Pen(New SolidBrush(System.Drawing.Color.Green), 2)))
End Sub
Public Class TelerikTagger
Inherits WordTaggerBase
Public Shared ReadOnly TelerikClassificationType As ClassificationType = New ClassificationType("Telerik")
Public Shared ReadOnly WordsToClassificationType As Dictionary(Of String, ClassificationType) = New Dictionary(Of String, ClassificationType)()
Public Sub New(ByVal editor As RadSyntaxEditorElement)
MyBase.New(editor)
WordsToClassificationType.Add("Telerik", TelerikClassificationType)
End Sub
Protected Overrides Function GetWordsToClassificationTypes() As Dictionary(Of String, ClassificationType)
Return TelerikTagger.WordsToClassificationType
End Function
End Class
Public Class CustomUILayersBuilder
Inherits Telerik.WinForms.Controls.SyntaxEditor.UI.Layers.UILayersBuilder
Public Overrides Sub BuildUILayers(ByVal uiLayers As UILayerStack)
MyBase.BuildUILayers(uiLayers)
uiLayers.AddLast(New MyTextUnderlineUILayer())
End Sub
End Class
Public Class MyTextUnderlineUILayer
Inherits LineBasedUILayer(Of ClassificationTag)
Public Overrides ReadOnly Property Name As String
Get
Return "MyTextUnderlineUILayer"
End Get
End Property
Protected Overrides Function GetLinePartUIElement(ByVal tag As ClassificationTag,
ByVal span As Telerik.WinForms.SyntaxEditor.Core.Text.Span,
ByVal updateContext As UIUpdateContext) As FrameworkElement
If Not tag.ClassificationType.Equals(TelerikTagger.TelerikClassificationType) Then
Return Nothing
End If
Dim textFormatting As TextFormatDefinition = updateContext.Editor.TextFormatDefinitions.GetTextFormatDefinition(TelerikTagger.TelerikClassificationType)
Dim rect As Telerik.WinControls.SyntaxEditor.UI.Rect = updateContext.Editor.GetLinePartBoundingRectangle(span, True)
Dim underlineRect As Rect = New Rect With {
.Y = rect.Height,
.Width = rect.Width,
.Height = updateContext.Editor.EditorFontSize / 16
}
Dim underline As FrameworkElement = Nothing
If textFormatting.Underline IsNot Nothing Then
underline = textFormatting.Underline.CreateUnderline(underlineRect)
End If
Return underline
End Function
Protected Overrides Sub ResetPooledElementProperties(ByVal element As Object)
End Sub
End Class