init method
初始化
Implementation
init(Size size) {
startX = basePadding;
endX = size.width - basePadding;
startY = size.height - basePadding;
endY = basePadding;
centerX = startX + (endX - startX) / 2;
centerY = endY + (startY - endY) / 2;
double xR = endX - centerX;
double yR = startY - centerY;
double realR = xR.compareTo(yR) > 0 ? yR : xR;
if (R == null || R == 0) {
R = realR;
} else {
if (R! > realR) R = realR;
}
if (centerR! > R!) centerR = R;
setPieAngle(); //计算角度
}