prepare method
Prepare the object to be written to the stream
Implementation
@override
void prepare() {
super.prepare();
params[PdfNameTokens.s] =
PdfName('/${'SDBIU'.substring(style.index, style.index + 1)}');
params[PdfNameTokens.w] = PdfNum(width);
if (dash != null) {
params[PdfNameTokens.d] = PdfArray.fromNum(dash!);
}
}