TextStyle getTextStyle({double textScaleFactor: 1.0 })

The style information for text runs, encoded for use by dart:ui.

Source 

ui.TextStyle getTextStyle({ double textScaleFactor: 1.0 }) {
  return new ui.TextStyle(
    color: color,
    decoration: decoration,
    decorationColor: decorationColor,
    decorationStyle: decorationStyle,
    fontWeight: fontWeight,
    fontStyle: fontStyle,
    textBaseline: textBaseline,
    fontFamily: fontFamily,
    fontSize: fontSize == null ? null : fontSize * textScaleFactor,
    letterSpacing: letterSpacing,
    wordSpacing: wordSpacing,
    height: height
  );
}