build method
Implementation
@override
Widget build(BuildContext context, List<Widget> legendEntries) {
final paddedLegendEntries = ((cellPadding == null)
? legendEntries
: legendEntries
.map((entry) => new Padding(padding: cellPadding!, child: entry))
.toList());
return isHorizontalFirst
? _buildHorizontalFirst(paddedLegendEntries)
: _buildVerticalFirst(paddedLegendEntries);
}