Evans测试

一个模型“Foo”单元类，它根据“单元”支持转换和不同的刻度格式。 这里的“单位”只是一个标量转换因子，但是这个例子表明Matplotlib完全不知道客户端软件包使用哪种单位。

Evans测试示例

  1. from matplotlib.cbook import iterable
  2. import matplotlib.units as units
  3. import matplotlib.ticker as ticker
  4. import matplotlib.pyplot as plt
  7. class Foo(object):
  8.     def __init__(self, val, unit=1.0):
  9.         self.unit = unit
  10.         self._val = val * unit
  12.     def value(self, unit):
  13.         if unit is None:
  14.             unit = self.unit
  15.         return self._val / unit
  18. class FooConverter(object):
  19.     @staticmethod
  20.     def axisinfo(unit, axis):
  21.         'return the Foo AxisInfo'
  22.         if unit == 1.0 or unit == 2.0:
  23.             return units.AxisInfo(
  24.                 majloc=ticker.IndexLocator(8, 0),
  25.                 majfmt=ticker.FormatStrFormatter("VAL: %s"),
  26.                 label='foo',
  27.                 )
  29.         else:
  30.             return None
  32.     @staticmethod
  33.     def convert(obj, unit, axis):
  34.         """
  35.         convert obj using unit.  If obj is a sequence, return the
  36.         converted sequence
  37.         """
  38.         if units.ConversionInterface.is_numlike(obj):
  39.             return obj
  41.         if iterable(obj):
  42.             return [o.value(unit) for o in obj]
  43.         else:
  44.             return obj.value(unit)
  46.     @staticmethod
  47.     def default_units(x, axis):
  48.         'return the default unit for x or None'
  49.         if iterable(x):
  50.             for thisx in x:
  51.                 return thisx.unit
  52.         else:
  53.             return x.unit
  56. units.registry[Foo] = FooConverter()
  58. # create some Foos
  59. x = []
  60. for val in range(0, 50, 2):
  61.     x.append(Foo(val, 1.0))
  63. # and some arbitrary y data
  64. y = [i for i in range(len(x))]
  67. fig, (ax1, ax2) = plt.subplots(1, 2)
  68. fig.suptitle("Custom units")
  69. fig.subplots_adjust(bottom=0.2)
  71. # plot specifying units
  72. ax2.plot(x, y, 'o', xunits=2.0)
  73. ax2.set_title("xunits = 2.0")
  74. plt.setp(ax2.get_xticklabels(), rotation=30, ha='right')
  76. # plot without specifying units; will use the None branch for axisinfo
  77. ax1.plot(x, y)  # uses default units
  78. ax1.set_title('default units')
  79. plt.setp(ax1.get_xticklabels(), rotation=30, ha='right')
  81. plt.show()

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