Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/graphviz/parameters/engines.py: 78%

1"""Rendering engine parameter handling.""" 

2 

3import typing 

4 

5from . import base 

6 

7__all__ = ['ENGINES', 'verify_engine', 'Engine'] 

8 

9ENGINES = {'dot', # https://www.graphviz.org/pdf/dot.1.pdf 

10 'neato', 

11 'twopi', 

12 'circo', 

13 'fdp', 

14 'sfdp', 

15 'patchwork', 

16 'osage'} 

17 

18DEFAULT_ENGINE = 'dot' 

19 

20REQUIRED = True 

21 

22 

23def verify_engine(engine: str, *, required: bool = REQUIRED) -> None: 

24 if engine is None: 

25 if required: 

26 raise ValueError('missing engine') 

27 elif engine.lower() not in ENGINES: 

28 raise ValueError(f'unknown engine: {engine!r}' 

29 f' (must be one of {sorted(ENGINES)})') 

30 

31 

32class Engine(base.ParameterBase): 

33 """Rendering engine parameter with ``'dot''`` default.""" 

34 

35 _engine = DEFAULT_ENGINE 

36 

37 _verify_engine = staticmethod(verify_engine) 

38 

39 def __init__(self, *, engine: typing.Optional[str] = None, **kwargs) -> None: 

40 super().__init__(**kwargs) 

41 

42 if engine is not None: 

43 self.engine = engine 

44 

45 def _copy_kwargs(self, **kwargs): 

46 """Return the kwargs to create a copy of the instance.""" 

47 engine = self._getattr_from_dict('_engine') 

48 if engine is not None: 

49 kwargs['engine'] = engine 

50 return super()._copy_kwargs(**kwargs) 

51 

52 @property 

53 def engine(self) -> str: 

54 """The layout engine used for rendering 

55 (``'dot'``, ``'neato'``, ...).""" 

56 return self._engine 

57 

58 @engine.setter 

59 def engine(self, engine: str) -> None: 

60 engine = engine.lower() 

61 self._verify_engine(engine) 

62 self._engine = engine