iOS 常见错误:CALayer position contains NaN: [14 nan]

Terminating app due to uncaught exception 'CALayerInvalidGeometry', reason: 'CALayer position contains NaN: [14 nan]'
*** First throw call stack:
  这个主要在画layer的时候,计算未考虑0的情况,在除数为0的时候就会报错,去检查把,骚年~~