toXML method
Convert the Svg structure to XML string
Implementation
@override
String toXML() {
var xml =
'<ellipse cx="${roundPixels(cx, unit)}" cy="${roundPixels(cx, unit)}" '
'rx="${roundPixels(rx, unit)}" ry="${roundPixels(ry, unit)}" '
'${attributes(id, fill, stroke, strokeWidth, strokeDasharray, style, transform, unit, visibility)} />';
return xml;
}