measure method
Implementation
void measure(Position position) {
// double width = legend.symbolSize.width;
// double height = legend.symbolSize.height;
// TextPainter painter = legend.labelStyle.textStyle.toPainter(legend.name);
// painter.layout();
// double textHeight = painter.height;
// double textWidth = painter.width;
// if (position == Position.left || position == Position.right) {
// width += textWidth + legend.margin;
// } else {
// height += textHeight + legend.margin;
// }
// rect = Rect.fromLTWH(0, 0, width, height);
}