CODEWITHSUNDEEP
c#.netwpf
user2506589
user2506589

Reputation: 155

Implementing atypical underline style

I need a special underline style for a rich textbox. The line/underline can have a different color than the text above it. The line should also have a shape that I haven't seen anywhere else.

Is it possible to implement this by leveraging some functionality, ideally inheriting from a rich text control?

I'm not sure how this can be done relatively easily so any hint is much appreciated. The only way I can think of is to implement it completely from scratch. E.g., using Graphics.DrawString, etc. Which would be awful lot of work.

I've also checked third-party controls like DevExpress, Telerik, Infragistics, ComponentOne, etc. But none of them seem to support this.

Upvotes: 0

Views: 105

Answers (1)

O. R. Mapper
O. R. Mapper

Reputation: 20770

The WPF RichTextBox control serves for editing FlowDocument instances, whose content is defined with the types from the System.Windows.Documents namespace.

Every Inline has a TextDecorations property. It is a list of additional decorations (generally, in the form of lines) that are added to the text of the inline. Each of them is an instance of the TextDecoration class.

Each TextDecoration gets its individual Pen, so the colour is independent from the text color. The following example creates a text comprising green letters, a purple underline and an orange overline:

<Run Foreground="Green" Text="Hello, World!" FontSize="36">
    <Run.TextDecorations>
        <TextDecoration Location="Underline">
            <TextDecoration.Pen>
                <Pen Brush="Purple"/>
            </TextDecoration.Pen>
        </TextDecoration>
        <TextDecoration Location="OverLine">
            <TextDecoration.Pen>
                <Pen Brush="Orange"/>
            </TextDecoration.Pen>
        </TextDecoration>
    </Run.TextDecorations>
</Run>

Once you're there, you can supply a brush that does not completely fill the area, but rather draws shapes, such as a VisualBrush, to create any pattern you want.

Upvotes: 1

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