requestedFontSize function
The font size of style before libmonet's size equalizer scaled it.
createTextTheme multiplies each role's size by visualHeightScaleForFontFamily, so that letters look the same size in every font. Thus the letter ink is proportional to this size, not to TextStyle.fontSize. Size things that sit next to text by it, so they match the letters in every font.
Implementation
double requestedFontSize(TextStyle style) =>
style.fontSize! / visualHeightScaleForFontFamily(style.fontFamily);