TextBlock as big as a capital letter (ignoring font ascender/descender)

Question

I am looking to get a specific behavior on TextBlock so that its height only includes the height of the capital letters (from baseline to top minus \"ascender h

Answer 1

u can try to use attribute LineStackingStrategy="BlockLineHeight" and a Converter on the LineHeight attributes and a converter on the Height of TextBlock. This a sample code of converters

// Height Converter
public class FontSizeToHeightConverter : IValueConverter
{
    public static double COEFF = 0.715;
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (double)value * COEFF;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}
// LineHeightConverter
public class FontSizeToLineHeightConverter : IValueConverter
{
    public static double COEFF = 0.875;
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return double.Parse(value.ToString()) * COEFF;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

The Coefficient used on converters depends on Used Family Fonts (Baseline and LineSpacing):

<TextBlock Text="ABC" Background="Aqua" LineStackingStrategy="BlockLineHeight" 
FontSize="{Binding ElementName=textBox1, Path=Text}" 
FontFamily="{Binding ElementName=listFonts, Path=SelectedItem}" 
Height="{Binding RelativeSource={RelativeSource Self}, Path=FontSize, Mode=OneWay, Converter={StaticResource FontSizeToHeightConverter1}}"
LineHeight="{Binding RelativeSource={RelativeSource Self}, Path=FontSize, Converter={StaticResource FontSizeToLineHeightConverter}}"/>

The best solution is to find how to calculate the Coeff based on parameters Baseline and LineSpacing of the FontFamily. In this sample (Segeo UI) the Coeff of Height = 0.715 and LineHeight = 0,875 * FontSize.

Answer 2

Updated:

If I understand right, there's a few tricks I know for this,

You can Scale it with RenderTransform which is usually the most efficient way;

<TextBlock Text="Blah">
  <TextBlock.RenderTransform>
   <CompositeTransform ScaleY="3"/>
  </TextBlock.RenderTransform>
</TextBlock>

Or you can embed the TextBlock in a Viewbox to "zoom" the text to fit the bounds of its container if for example you set hard height values on grid rows like;

<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="120"/>
<RowDefinition Height="120"/>
</Grid.RowDefinitions>
<Viewbox VerticalAlignment="Stretch" Height="Auto">
      <!-- The textblock and its contents are 
      stretched to fill its parent -->
      <TextBlock Text="Sphinx" />
</Viewbox>
<Viewbox Grid.Row="2" VerticalAlignment="Stretch" Height="Auto">
      <!-- The textblock and its contents are 
      stretched to fill its parent -->
      <TextBlock Text="Sphinx2" />
</Viewbox>

or you can bind the FontSize to a Container element like;

<Grid x:Name="MyText" Height="120">
<TextBlock FontSize="{Binding ElementName=MyText, Path=Height}" Text="Sphinx" />
</Grid>

They might present the effect you're after?