init method
初始化 耗时的方法都可以放到这里
Implementation
@override
void init(ChartsState state) {
super.init(state);
_ChartCircularCoordinateState layout = state.layout as _ChartCircularCoordinateState;
Offset center = layout.center;
double radius = layout.radius;
//处理圆形场景
if (layout.arcPosition == ArcPosition.none) {
Offset progressCenter = Offset(center.dx, center.dy + radius);
_transform = TransformUtils(
anchor: progressCenter,
size: layout.size,
offset: layout.offset,
padding: layout.padding,
reverseX: false,
reverseY: true,
);
} else {
//半圆就不用特别处理了
_transform = layout.transform;
}
}