TextFormat(String font, num size, int color, { num strokeWidth: 0.0, int strokeColor: Color.Black, GraphicsGradient fillGradient: null, int weight: 400, bool bold: false, bool italic: false, bool underline: false, String align: "left", num topMargin: 0.0, num bottomMargin: 0.0, num leftMargin: 0.0, num rightMargin: 0.0, num indent: 0.0, num leading: 0.0 })

Source 

TextFormat(this.font, this.size, this.color, {
  this.strokeWidth  : 0.0,
  this.strokeColor  : Color.Black,
  this.fillGradient : null,
  this.weight       : 400,
  this.bold         : false,
  this.italic       : false,
  this.underline    : false,
  this.align        : "left",
  this.topMargin    : 0.0,
  this.bottomMargin : 0.0,
  this.leftMargin   : 0.0,
  this.rightMargin  : 0.0,
  this.indent       : 0.0,
  this.leading      : 0.0
});