toXML method Null safety

@override String toXML()

Convert the Svg structure to XML string

Implementation

@override
String toXML() {
  var xml =
      '<circle cx="${roundPixels(cx, unit)}" cy="${roundPixels(cy, unit)}" '
      'r="${roundPixels(r, unit)}" '
      '${attributes(id, fill, stroke, strokeWidth, strokeDasharray, style, transform, unit, visibility)} />';
  return xml;
}