If you create a C#/VB/C++ app using one of the Visual Studio template, you'll find a file
Common/StandardStyles.xaml. It contains a base style called AppBarButtonStyle.
Here is the code for that style. I think the text you are talking about is the TextBlock named
TextLabel and its fontsize is 12 :
<Style x:Key="AppBarButtonStyle" TargetType="ButtonBase">
<Setter Property="Foreground" Value="{StaticResource AppBarItemForegroundThemeBrush}"/>
<Setter Property="VerticalAlignment" Value="Stretch"/>
<Setter Property="FontFamily" Value="Segoe UI Symbol"/>
<Setter Property="FontWeight" Value="Normal"/>
<Setter Property="FontSize" Value="20"/>
<Setter Property="AutomationProperties.ItemType" Value="App Bar Button"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ButtonBase">
<Grid x:Name="RootGrid" Width="100" Background="Transparent">
<StackPanel VerticalAlignment="Top" Margin="0,12,0,11">
<Grid Width="40" Height="40" Margin="0,0,0,5" HorizontalAlignment="Center">
<TextBlock x:Name="BackgroundGlyph" Text="" FontFamily="Segoe UI Symbol" FontSize="53.333" Margin="-4,-19,0,0" Foreground="{StaticResource AppBarItemBackgroundThemeBrush}"/>
<TextBlock x:Name="OutlineGlyph" Text="" FontFamily="Segoe UI Symbol" FontSize="53.333" Margin="-4,-19,0,0"/>
<ContentPresenter x:Name="Content" HorizontalAlignment="Center" Margin="-1,-1,0,0" VerticalAlignment="Center"/>
</Grid>
<TextBlock
x:Name="TextLabel"
Text="{TemplateBinding AutomationProperties.Name}"
Foreground="{StaticResource AppBarItemForegroundThemeBrush}"
Margin="0,0,2,0"
FontSize="12"
TextAlignment="Center"
Width="88"
MaxHeight="32"
TextTrimming="WordEllipsis"
Style="{StaticResource BasicTextStyle}"/>
</StackPanel>
<Rectangle
x:Name="FocusVisualWhite"
IsHitTestVisible="False"
Stroke="{StaticResource FocusVisualWhiteStrokeThemeBrush}"
StrokeEndLineCap="Square"
StrokeDashArray="1,1"
Opacity="0"
StrokeDashOffset="1.5"/>
<Rectangle
x:Name="FocusVisualBlack"
IsHitTestVisible="False"
Stroke="{StaticResource FocusVisualBlackStrokeThemeBrush}"
StrokeEndLineCap="Square"
StrokeDashArray="1,1"
Opacity="0"
StrokeDashOffset="0.5"/>
<VisualStateManager.VisualStateGroups>
<!-- I removed that part to make it shorter... -->
</VisualStateManager.VisualStateGroups>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Best regards,
Renaud
http://www.renauddumont.be