Вот мой код (немного измененный):
public class SimpleTextBlock : FrameworkElement
{
#region Static
private const double _fontSize = 12;
private static Point _emptyPoint;
private static Typeface _typeface;
private static LinearGradientBrush _textBrush;
public readonly static DependencyProperty TextWidthProperty;
static SimpleTextBlock()
{
_emptyPoint = new Point();
_typeface = new Typeface(new FontFamily("Sergoe UI"), FontStyles.Normal, FontWeights.Normal, FontStretches.Normal);
GradientStopCollection GSC = new GradientStopCollection(2);
GSC.Add(new GradientStop(Color.FromArgb(160, 255, 255, 255), 0.0));
GSC.Add(new GradientStop(Color.FromArgb(160, 180, 200, 255), 0.7));
_textBrush = new LinearGradientBrush(GSC, 90);
_textBrush.Freeze();
SimpleTextBlock.TextWidthProperty = DependencyProperty.Register(
"TextWidth",
typeof(double),
typeof(SimpleTextBlock),
new FrameworkPropertyMetadata(0.0d, FrameworkPropertyMetadataOptions.AffectsRender));
}
#endregion
FormattedText _formattedText;
public SimpleTextBlock(string text)
{
_formattedText = new FormattedText(text, System.Globalization.CultureInfo.InvariantCulture, FlowDirection.LeftToRight, _typeface, _fontSize, _textBrush);
}
public SimpleTextBlock(string text, FlowDirection FlowDirection)
{
_formattedText = new FormattedText(text, System.Globalization.CultureInfo.InvariantCulture, FlowDirection, _typeface, _fontSize, _textBrush);
}
protected override void OnRender(DrawingContext drawingContext)
{
_formattedText.MaxTextWidth = (double)GetValue(TextWidthProperty);
drawingContext.DrawText(_formattedText, _emptyPoint);
}
public double TextWidth
{
get { return (double)base.GetValue(TextWidthProperty); }
set { base.SetValue(TextWidthProperty, value); }
}
public double ActualTextWidth
{
get { return _formattedText.Width; }
}
public double ActualTextHeight
{
get { return _formattedText.Height; }
}
}