Use a PathGeometry object to highlight displayed text. : Geometry « Windows Presentation Foundation « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Windows Presentation Foundation
3. Geometry

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="WpfApplication1.Window1"
  Title="Using a Path Geometry to Highlight Text"
  Background="PowderBlue">

  <StackPanel>
      <Button Margin="10" Grid.Column="2" Grid.Row="0" FontSize="16" Click="OnDisplayTextClick">Display Text</Button>
    <Canvas Margin="20" Height="150">
      <Path Canvas.Top="15" Canvas.Left="15" Stroke="SteelBlue" StrokeThickness="3" Fill="LightSteelBlue" Name="path" />
      <Ellipse Canvas.Top="0" Canvas.Left="0" Width="30" Height="30">
        <Ellipse.Fill>
          <RadialGradientBrush GradientOrigin="0.5,0.5" Center="0.5,0.5" RadiusX="0.5" RadiusY="0.5">
            <RadialGradientBrush.GradientStops>
              <GradientStop Color="Yellow" Offset="0.25" />
              <GradientStop Color="Transparent" Offset="1" />
            </RadialGradientBrush.GradientStops>
          </RadialGradientBrush>
        </Ellipse.Fill>

        <Ellipse.RenderTransform>
          <MatrixTransform />
        </Ellipse.RenderTransform>
        <Ellipse.Triggers>
          <EventTrigger RoutedEvent="FrameworkElement.Loaded">
            <EventTrigger.Actions>
            <BeginStoryboard>
              <Storyboard x:Name="storyboard">
                <MatrixAnimationUsingPath 
                  x:Name="matrixAnimation"
                  Duration="0:00:40"
                  RepeatBehavior="Forever"
                  Storyboard.TargetProperty="RenderTransform.Matrix" />
              </Storyboard>
            </BeginStoryboard>
            </EventTrigger.Actions>
          </EventTrigger>
        </Ellipse.Triggers>
      </Ellipse>
    </Canvas>
  </StackPanel>
</Window>

//File:Window.xaml.cs

using System;
using System.Globalization;
using System.Windows;
using System.Windows.Media;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {     
        public Window1()
        {
            InitializeComponent();
        }

        public void OnDisplayTextClick(object sender, EventArgs e)
        {
            FormattedText formattedText = new FormattedText(
                "asdf",
                CultureInfo.GetCultureInfo("en-us"),
                FlowDirection.LeftToRight,
                new Typeface("Verdana"),
                96,
                Brushes.Black);

            formattedText.SetFontWeight(FontWeights.Bold);

            Geometry geometry = formattedText.BuildGeometry(new Point(0, 0));

            PathGeometry pathGeometry = geometry.GetFlattenedPathGeometry();

            path.Data = pathGeometry;

            matrixAnimation.PathGeometry = pathGeometry;
        }
    }
}

24.105.Geometry
	24.105.1.	LineGeometry
	24.105.2.	EllipseGeometry
	24.105.3.	RectangleGeometry
	24.105.4.	Animate GeometryDrawing Examples
	24.105.5.	CombinedGeometry for Path.Data and DrawingBrush for Path.Fill
	24.105.6.	Combines two geometries using the XOR combine mode
	24.105.7.	Combines two geometries using the union combine mode
	24.105.8.	Combines two geometries using the exclude combine mode
	24.105.9.	Geometry Transform for Rectangle
	24.105.10.	Geometry Transform for Path
	24.105.11.	Geometry Used with a DrawingBrush
	24.105.12.	Geometry Used as a Clip
	24.105.13.	Tiled Geometry
	24.105.14.	Ellipse Geometry Demo
	24.105.15.	LineGeometry Demo
	24.105.16.	Use PolyBezierSegment to Simulated Circle
	24.105.17.	Converting text to geometry
	24.105.18.	Use a PathGeometry object to highlight displayed text.
	24.105.19.	Shape Exclude
	24.105.20.	Shape Xor
	24.105.21.	Shape Union