I want to render some text on DrawingContext object, which should have font size, specified in pt units. For this purpose I am using FormattedText object. But this object has weird (for me) constructor:
public FormattedText(string textToFormat, CultureInfo culture, FlowDirection flowDirection, Typeface typeface, double emSize, Brush foreground);
It requires that font size should be in em units. But as far as I know, one em unit equals the current font size. How can I know that font size?