Cleanup of scales docs

timhoffm · timhoffm · commit 795023a75920 · 2019-06-29T21:43:24.000+02:00
diff --git a/lib/matplotlib/scale.py b/lib/matplotlib/scale.py
@@ -1,3 +1,12 @@
+"""
+Scales define the distribution of data values on an axis, e.g. a log scaling.
+
+They are attached to an `~.axis.Axis` and hold a `.Transform`, which is
+responsible for the actual data transformation.
+
+See also `.axes.Axes.set_xscale` and the scales examples in the documentation.
+"""
+
 import inspect
 import textwrap
 
@@ -20,12 +29,14 @@ class ScaleBase:
 
     Any subclasses will want to override:
 
-      - :attr:`name`
-      - :meth:`get_transform`
-      - :meth:`set_default_locators_and_formatters`
+    - :attr:`name`
+    - :meth:`get_transform`
+    - :meth:`set_default_locators_and_formatters`
 
     And optionally:
-      - :meth:`limit_range_for_scale`
+
+    - :meth:`limit_range_for_scale`
+
     """
 
     def __init__(self, axis, **kwargs):
@@ -51,9 +62,8 @@ def get_transform(self):
 
     def set_default_locators_and_formatters(self, axis):
         """
-        Set the :class:`~matplotlib.ticker.Locator` and
-        :class:`~matplotlib.ticker.Formatter` objects on the given
-        axis to match this scale.
+        Set the locators and formatters of *axis* to instances suitable for
+        this scale.
         """
         raise NotImplementedError()
 
@@ -63,7 +73,7 @@ def limit_range_for_scale(self, vmin, vmax, minpos):
         domain supported by this scale.
 
         *minpos* should be the minimum positive value in the data.
-         This is used by log scales to determine a minimum value.
+        This is used by log scales to determine a minimum value.
         """
         return vmin, vmax
 
@@ -84,10 +94,7 @@ def __init__(self, axis, **kwargs):
         super().__init__(axis, **kwargs)
 
     def set_default_locators_and_formatters(self, axis):
-        """
-        Set the locators and formatters to reasonable defaults for
-        linear scaling.
-        """
+        # docstring inherited
         axis.set_major_locator(AutoLocator())
         axis.set_major_formatter(ScalarFormatter())
         axis.set_minor_formatter(NullFormatter())
@@ -100,8 +107,8 @@ def set_default_locators_and_formatters(self, axis):
 
     def get_transform(self):
         """
-        The transform for linear scaling is just the
-        :class:`~matplotlib.transforms.IdentityTransform`.
+        Return the transform for linear scaling, which is just the
+        `~matplotlib.transforms.IdentityTransform`.
         """
         return IdentityTransform()
 
@@ -157,8 +164,8 @@ def __init__(self, axis, functions):
         """
         Parameters
         ----------
-        axis: the axis for the scale
-
+        axis : `matplotlib.axis.Axis`
+            The axis for the scale.
         functions : (callable, callable)
             two-tuple of the forward and inverse functions for the scale.
             The forward function must be monotonic.
@@ -172,16 +179,12 @@ def forward(values: array-like) -> array-like
         self._transform = transform
 
     def get_transform(self):
-        """
-        The transform for arbitrary scaling
-        """
+        """Return the `.FuncTransform` associated with this scale."""
+        # docstring inherited
         return self._transform
 
     def set_default_locators_and_formatters(self, axis):
-        """
-        Set the locators and formatters to the same defaults as the
-        linear scale.
-        """
+        # docstring inherited
         axis.set_major_locator(AutoLocator())
         axis.set_major_formatter(ScalarFormatter())
         axis.set_minor_formatter(NullFormatter())
@@ -354,18 +357,17 @@ class LogScale(ScaleBase):
 
     def __init__(self, axis, **kwargs):
         """
-        *basex*/*basey*:
+        Parameters
+        ----------
+        basex, basey : float
            The base of the logarithm
-
-        *nonposx*/*nonposy*: {'mask', 'clip'}
-          non-positive values in *x* or *y* can be masked as
-          invalid, or clipped to a very small positive number
-
-        *subsx*/*subsy*:
+        nonposx, nonposy : {'mask', 'clip'}
+            Determines the behavior for non-positive values. They can either
+            be masked as invalid, or clipped to a number very small positive
+            number.
+        subsx, subsy : sequence of int
            Where to place the subticks between each major tick.
-           Should be a sequence of integers.  For example, in a log10
-           scale: ``[2, 3, 4, 5, 6, 7, 8, 9]``
-
+           For example, in a log10 scale: ``[2, 3, 4, 5, 6, 7, 8, 9]``
            will place 8 logarithmically spaced minor ticks between
            each major tick.
         """
@@ -397,10 +399,7 @@ def base(self):
         return self._transform.base
 
     def set_default_locators_and_formatters(self, axis):
-        """
-        Set the locators and formatters to specialized versions for
-        log scaling.
-        """
+        # docstring inherited
         axis.set_major_locator(LogLocator(self.base))
         axis.set_major_formatter(LogFormatterSciNotation(self.base))
         axis.set_minor_locator(LogLocator(self.base, self.subs))
@@ -409,10 +408,7 @@ def set_default_locators_and_formatters(self, axis):
                                     labelOnlyBase=(self.subs is not None)))
 
     def get_transform(self):
-        """
-        Return a :class:`~matplotlib.transforms.Transform` instance
-        appropriate for the given logarithm base.
-        """
+        """Return the `.LogTransform` associated with this scale."""
         return self._transform
 
     def limit_range_for_scale(self, vmin, vmax, minpos):
@@ -438,8 +434,8 @@ def __init__(self, axis, functions, base=10):
         """
         Parameters
         ----------
-        axis: the axis for the scale
-
+        axis : `matplotlib.axis.Axis`
+            The axis for the scale.
         functions : (callable, callable)
             two-tuple of the forward and inverse functions for the scale.
             The forward function must be monotonic.
@@ -461,9 +457,7 @@ def base(self):
         return self._transform._b.base  # Base of the LogTransform.
 
     def get_transform(self):
-        """
-        The transform for arbitrary scaling
-        """
+        """Return the `.Transform` associated with this scale."""
         return self._transform
 
 
@@ -592,20 +586,15 @@ def __init__(self, axis, **kwargs):
         self.subs = subs
 
     def set_default_locators_and_formatters(self, axis):
-        """
-        Set the locators and formatters to specialized versions for
-        symmetrical log scaling.
-        """
+        # docstring inherited
         axis.set_major_locator(SymmetricalLogLocator(self.get_transform()))
         axis.set_major_formatter(LogFormatterSciNotation(self.base))
         axis.set_minor_locator(SymmetricalLogLocator(self.get_transform(),
                                                      self.subs))
         axis.set_minor_formatter(NullFormatter())
 
     def get_transform(self):
-        """
-        Return a :class:`SymmetricalLogTransform` instance.
-        """
+        """Return the `.SymmetricalLogTransform` associated with this scale."""
         return self._transform
 
 
@@ -669,19 +658,22 @@ class LogitScale(ScaleBase):
 
     def __init__(self, axis, nonpos='mask'):
         """
-        *nonpos*: {'mask', 'clip'}
-          values beyond ]0, 1[ can be masked as invalid, or clipped to a number
-          very close to 0 or 1
+        Parameters
+        ----------
+        axis : `matplotlib.axis.Axis`
+            Currently used.
+        nonpos : {'mask', 'clip'}
+            Determines the behavior for values beyond ]0, 1[. They can either
+            be masked as invalid, or clipped to a number very close to 0 or 1.
         """
         self._transform = LogitTransform(nonpos)
 
     def get_transform(self):
-        """
-        Return a :class:`LogitTransform` instance.
-        """
+        """Return the `.LogitTransform` associated with this scale."""
         return self._transform
 
     def set_default_locators_and_formatters(self, axis):
+        # docstring inherited
         # ..., 0.01, 0.1, 0.5, 0.9, 0.99, ...
         axis.set_major_locator(LogitLocator())
         axis.set_major_formatter(LogitFormatter())
@@ -709,6 +701,7 @@ def limit_range_for_scale(self, vmin, vmax, minpos):
 
 
 def get_scale_names():
+    """Return the names of the available scales."""
     return sorted(_scale_mapping)
 
 
@@ -719,22 +712,25 @@ def scale_factory(scale, axis, **kwargs):
     Parameters
     ----------
     scale : {%(names)s}
-    axis : Axis
+    axis : `matplotlib.axis.Axis`
     """
     scale = scale.lower()
     cbook._check_in_list(_scale_mapping, scale=scale)
     return _scale_mapping[scale](axis, **kwargs)
 
 if scale_factory.__doc__:
     scale_factory.__doc__ = scale_factory.__doc__ % {
-        "names": ", ".join(get_scale_names())}
+        "names": ", ".join(f"'{s}'" for s in get_scale_names())}
 
 
 def register_scale(scale_class):
     """
     Register a new kind of scale.
 
-    *scale_class* must be a subclass of :class:`ScaleBase`.
+    Parameters
+    ----------
+    scale_class : subclass of `ScaleBase`
+        The scale to register.
     """
     _scale_mapping[scale_class.name] = scale_class
 
diff --git a/lib/matplotlib/transforms.py b/lib/matplotlib/transforms.py
@@ -1188,18 +1188,18 @@ class Transform(TransformNode):
     Subclasses of this class should override the following members (at
     minimum):
 
-      - :attr:`input_dims`
-      - :attr:`output_dims`
-      - :meth:`transform`
-      - :attr:`is_separable`
-      - :attr:`has_inverse`
-      - :meth:`inverted` (if :attr:`has_inverse` is True)
+    - :attr:`input_dims`
+    - :attr:`output_dims`
+    - :meth:`transform`
+    - :attr:`is_separable`
+    - :attr:`has_inverse`
+    - :meth:`inverted` (if :attr:`has_inverse` is True)
 
     If the transform needs to do something non-standard with
     :class:`matplotlib.path.Path` objects, such as adding curves
     where there were once line segments, it should override:
 
-      - :meth:`transform_path`
+    - :meth:`transform_path`
     """
     input_dims = None
     """
@@ -1403,11 +1403,17 @@ def transform_affine(self, values):
         affine transformations, this is equivalent to
         ``transform(values)``.
 
-        Accepts a numpy array of shape (N x :attr:`input_dims`) and
-        returns a numpy array of shape (N x :attr:`output_dims`).
+        Parameters
+        ----------
+        values : array
+            The input values as numpy array of length :attr:`input_dims` or
+            shape (N x :attr:`input_dims`).
 
-        Alternatively, accepts a numpy array of length :attr:`input_dims`
-        and returns a numpy array of length :attr:`output_dims`.
+        Returns
+        -------
+        values : array
+            The output values as numpy array of length :attr:`input_dims` or
+            shape (N x :attr:`output_dims`), depending on the input.
         """
         return self.get_affine().transform(values)
 
@@ -1422,11 +1428,17 @@ def transform_non_affine(self, values):
         ``transform(values)``.  In affine transformations, this is
         always a no-op.
 
-        Accepts a numpy array of shape (N x :attr:`input_dims`) and
-        returns a numpy array of shape (N x :attr:`output_dims`).
+        Parameters
+        ----------
+        values : array
+            The input values as numpy array of length :attr:`input_dims` or
+            shape (N x :attr:`input_dims`).
 
-        Alternatively, accepts a numpy array of length :attr:`input_dims`
-        and returns a numpy array of length :attr:`output_dims`.
+        Returns
+        -------
+        values : array
+            The output values as numpy array of length :attr:`input_dims` or
+            shape (N x :attr:`output_dims`), depending on the input.
         """
         return values
 
@@ -1555,11 +1567,11 @@ def inverted(self):
         """
         Return the corresponding inverse transformation.
 
+        It holds ``x == self.inverted().transform(self.transform(x))``.
+
         The return value of this method should be treated as
         temporary.  An update to *self* does not cause a corresponding
         update to its inverted copy.
-
-        ``x === self.inverted().transform(self.transform(x))``
         """
         raise NotImplementedError()
 
