Changing the font size of an element programmatically inside a Viewbox works weird-CodePudding

I need to change the font size of a label programmatically. The label is located inside a Viewbox:

<Window ...
        FontSize="24"
        HorizontalAlignment="Center" VerticalAlignment="Center"
        WindowStyle="ThreeDBorderWindow"
        ResizeMode="NoResize">
    <Grid>
        <Viewbox x:Name="vb" Stretch="Uniform">
            <Label x:Name="label1" HorizontalContentAlignment="Center" Content="Text"/>
        </Viewbox>
    </Grid>
</Window>

The font size of text inside the label is assumed to be 24. However, even if I set it in my code like this to its 'original' value in xaml:

label1.FontSize = 24;

it becomes smaller.

Is there a simple way to keep the ratio between the new font size and the scale factor of the Viewbox?

CodePudding user response：

You can try to set ViewBox.StretchDirection property to DownOnly, for the label will be smaller, but not bigger:

<StackPanel Width="200" >
   <Label Content="Text" FontSize="24" HorizontalAlignment="Center"/>
   <Viewbox StretchDirection="DownOnly" Stretch="Uniform">
      <Label Content="Text" FontSize="24"/>
   </Viewbox>
   <Viewbox StretchDirection="DownOnly" Stretch="Uniform">
      <Label Content="ABCDEF EEEEE ABCDEFGJKLMNOP" FontSize="24"/>
   </Viewbox>
</StackPanel>

So the code results to :