LineUtils constructor Null safety

1. geometry_kit
2. geometry_kit
3. LineUtils
4. LineUtils constructor

LineUtils class

1. Constructors
2. LineUtils
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. Operators
10. operator ==
11. Static methods
12. angleOf2Lines
13. getSegmentIntersect
14. isPointBelongToLineSegment
15. isTwoLineSegmentsIntersect
16. lineLength
17. midPoint
18. pointToLineDistance