transform method
Implementation
void transform(PointTransformer f) {
final anchor0 = f(anchor0X, anchor0Y);
final control0 = f(control0X, control0Y);
final control1 = f(control1X, control1Y);
final anchor1 = f(anchor1X, anchor1Y);
anchor0X = anchor0.$1;
anchor0Y = anchor0.$2;
control0X = control0.$1;
control0Y = control0.$2;
control1X = control1.$1;
control1Y = control1.$2;
anchor1X = anchor1.$1;
anchor1Y = anchor1.$2;
}