@@ -1651,19 +1651,23 @@ class BoundaryNorm(Normalize):
16511651
16521652 Unlike `Normalize` or `LogNorm`, `BoundaryNorm` maps values to integers
16531653 instead of to the interval 0-1.
1654-
1655- Mapping to the 0-1 interval could have been done via piece-wise linear
1656- interpolation, but using integers seems simpler, and reduces the number of
1657- conversions back and forth between integer and floating point.
16581654 """
1655+ 1656+ # Mapping to the 0-1 interval could have been done via piece-wise linear
1657+ # interpolation, but using integers seems simpler, and reduces the number
1658+ # of conversions back and forth between int and float.
1659+ 16591660 def __init__ (self , boundaries , ncolors , clip = False , * , extend = 'neither' ):
16601661 """
16611662 Parameters
16621663 ----------
16631664 boundaries : array-like
1664- Monotonically increasing sequence of at least 2 boundaries.
1665+ Monotonically increasing sequence of at least 2 bin edges: data
1666+ falling in the n-th bin will be mapped to the n-th color.
1667+
16651668 ncolors : int
16661669 Number of colors in the colormap to be used.
1670+
16671671 clip : bool, optional
16681672 If clip is ``True``, out of range values are mapped to 0 if they
16691673 are below ``boundaries[0]`` or mapped to ``ncolors - 1`` if they
@@ -1673,6 +1677,7 @@ def __init__(self, boundaries, ncolors, clip=False, *, extend='neither'):
16731677 they are below ``boundaries[0]`` or mapped to *ncolors* if they are
16741678 above ``boundaries[-1]``. These are then converted to valid indices
16751679 by `Colormap.__call__`.
1680+
16761681 extend : {'neither', 'both', 'min', 'max'}, default: 'neither'
16771682 Extend the number of bins to include one or both of the
16781683 regions beyond the boundaries. For example, if ``extend``
@@ -1682,18 +1687,12 @@ def __init__(self, boundaries, ncolors, clip=False, *, extend='neither'):
16821687 `~matplotlib.colorbar.Colorbar` will be drawn with
16831688 the triangle extension on the left or lower end.
16841689
1685- Returns
1686- -------
1687- int16 scalar or array
1688-
16891690 Notes
16901691 -----
1691- *boundaries* defines the edges of bins, and data falling within a bin
1692- is mapped to the color with the same index.
1693-
1694- If the number of bins, including any extensions, is less than
1695- *ncolors*, the color index is chosen by linear interpolation, mapping
1696- the ``[0, nbins - 1]`` range onto the ``[0, ncolors - 1]`` range.
1692+ If there are fewer bins (including extensions) than colors, then the
1693+ color index is chosen by linearly interpolating the ``[0, nbins - 1]``
1694+ range onto the ``[0, ncolors - 1]`` range, effectively skipping some
1695+ colors in the middle of the colormap.
16971696 """
16981697 if clip and extend != 'neither' :
16991698 raise ValueError ("'clip=True' is not compatible with 'extend'" )
@@ -1722,6 +1721,10 @@ def __init__(self, boundaries, ncolors, clip=False, *, extend='neither'):
17221721 "number of bins" )
17231722
17241723 def __call__ (self , value , clip = None ):
1724+ """
1725+ This method behaves similarly to `.Normalize.__call__`, except that it
1726+ returns integers or arrays of int16.
1727+ """
17251728 if clip is None :
17261729 clip = self .clip
17271730
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