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1781 lines (1475 loc) · 66.6 KB
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"""
These are classes to support contour plotting and labelling for the Axes class.
"""
from numbers import Integral
import numpy as np
from numpy import ma
import matplotlib as mpl
import matplotlib.path as mpath
import matplotlib.ticker as ticker
import matplotlib.cm as cm
import matplotlib.colors as mcolors
import matplotlib.collections as mcoll
import matplotlib.font_manager as font_manager
import matplotlib.text as text
import matplotlib.cbook as cbook
import matplotlib.mathtext as mathtext
import matplotlib.patches as mpatches
import matplotlib.texmanager as texmanager
import matplotlib.transforms as mtransforms
# Import needed for adding manual selection capability to clabel
from matplotlib.blocking_input import BlockingContourLabeler
# We can't use a single line collection for contour because a line
# collection can have only a single line style, and we want to be able to have
# dashed negative contours, for example, and solid positive contours.
# We could use a single polygon collection for filled contours, but it
# seems better to keep line and filled contours similar, with one collection
# per level.
class ClabelText(text.Text):
"""
Unlike the ordinary text, the get_rotation returns an updated
angle in the pixel coordinate assuming that the input rotation is
an angle in data coordinate (or whatever transform set).
"""
def get_rotation(self):
new_angle, = self.get_transform().transform_angles(
[text.Text.get_rotation(self)], [self.get_position()])
return new_angle
class ContourLabeler:
"""Mixin to provide labelling capability to `.ContourSet`."""
def clabel(self, levels=None, *,
fontsize=None, inline=True, inline_spacing=5, fmt='%1.3f',
colors=None, use_clabeltext=False, manual=False,
rightside_up=True):
"""
Label a contour plot.
Adds labels to line contours in this `.ContourSet` (which inherits from
this mixin class).
Parameters
----------
levels : array-like, optional
A list of level values, that should be labeled. The list must be
a subset of ``cs.levels``. If not given, all levels are labeled.
fontsize : str or float, default: :rc:`font.size`
Size in points or relative size e.g., 'smaller', 'x-large'.
See `.Text.set_size` for accepted string values.
colors : color-spec, optional
The label colors:
- If *None*, the color of each label matches the color of
the corresponding contour.
- If one string color, e.g., *colors* = 'r' or *colors* =
'red', all labels will be plotted in this color.
- If a tuple of colors (string, float, rgb, etc), different labels
will be plotted in different colors in the order specified.
inline : bool, default: True
If ``True`` the underlying contour is removed where the label is
placed.
inline_spacing : float, default: 5
Space in pixels to leave on each side of label when placing inline.
This spacing will be exact for labels at locations where the
contour is straight, less so for labels on curved contours.
fmt : str or dict, default: '%1.3f'
A format string for the label.
Alternatively, this can be a dictionary matching contour levels
with arbitrary strings to use for each contour level (i.e.,
fmt[level]=string), or it can be any callable, such as a
`.Formatter` instance, that returns a string when called with a
numeric contour level.
manual : bool or iterable, optional
If ``True``, contour labels will be placed manually using
mouse clicks. Click the first button near a contour to
add a label, click the second button (or potentially both
mouse buttons at once) to finish adding labels. The third
button can be used to remove the last label added, but
only if labels are not inline. Alternatively, the keyboard
can be used to select label locations (enter to end label
placement, delete or backspace act like the third mouse button,
and any other key will select a label location).
*manual* can also be an iterable object of (x, y) tuples.
Contour labels will be created as if mouse is clicked at each
(x, y) position.
rightside_up : bool, default: True
If ``True``, label rotations will always be plus
or minus 90 degrees from level.
use_clabeltext : bool, default: False
If ``True``, `.ClabelText` class (instead of `.Text`) is used to
create labels. `ClabelText` recalculates rotation angles
of texts during the drawing time, therefore this can be used if
aspect of the axes changes.
Returns
-------
labels
A list of `.Text` instances for the labels.
"""
# clabel basically takes the input arguments and uses them to
# add a list of "label specific" attributes to the ContourSet
# object. These attributes are all of the form label* and names
# should be fairly self explanatory.
#
# Once these attributes are set, clabel passes control to the
# labels method (case of automatic label placement) or
# `BlockingContourLabeler` (case of manual label placement).
self.labelFmt = fmt
self._use_clabeltext = use_clabeltext
# Detect if manual selection is desired and remove from argument list.
self.labelManual = manual
self.rightside_up = rightside_up
if levels is None:
levels = self.levels
indices = list(range(len(self.cvalues)))
else:
levlabs = list(levels)
indices, levels = [], []
for i, lev in enumerate(self.levels):
if lev in levlabs:
indices.append(i)
levels.append(lev)
if len(levels) < len(levlabs):
raise ValueError(f"Specified levels {levlabs} don't match "
f"available levels {self.levels}")
self.labelLevelList = levels
self.labelIndiceList = indices
self.labelFontProps = font_manager.FontProperties()
self.labelFontProps.set_size(fontsize)
font_size_pts = self.labelFontProps.get_size_in_points()
self.labelFontSizeList = [font_size_pts] * len(levels)
if colors is None:
self.labelMappable = self
self.labelCValueList = np.take(self.cvalues, self.labelIndiceList)
else:
cmap = mcolors.ListedColormap(colors, N=len(self.labelLevelList))
self.labelCValueList = list(range(len(self.labelLevelList)))
self.labelMappable = cm.ScalarMappable(cmap=cmap,
norm=mcolors.NoNorm())
self.labelXYs = []
if np.iterable(self.labelManual):
for x, y in self.labelManual:
self.add_label_near(x, y, inline, inline_spacing)
elif self.labelManual:
print('Select label locations manually using first mouse button.')
print('End manual selection with second mouse button.')
if not inline:
print('Remove last label by clicking third mouse button.')
blocking_contour_labeler = BlockingContourLabeler(self)
blocking_contour_labeler(inline, inline_spacing)
else:
self.labels(inline, inline_spacing)
self.labelTextsList = cbook.silent_list('text.Text', self.labelTexts)
return self.labelTextsList
def print_label(self, linecontour, labelwidth):
"""Return *False* if contours are too short for a label."""
return (len(linecontour) > 10 * labelwidth
or (np.ptp(linecontour, axis=0) > 1.2 * labelwidth).any())
def too_close(self, x, y, lw):
"""Return *True* if a label is already near this location."""
thresh = (1.2 * lw) ** 2
return any((x - loc[0]) ** 2 + (y - loc[1]) ** 2 < thresh
for loc in self.labelXYs)
def get_label_coords(self, distances, XX, YY, ysize, lw):
"""
Return x, y, and the index of a label location.
Labels are plotted at a location with the smallest
deviation of the contour from a straight line
unless there is another label nearby, in which case
the next best place on the contour is picked up.
If all such candidates are rejected, the beginning
of the contour is chosen.
"""
hysize = int(ysize / 2)
adist = np.argsort(distances)
for ind in adist:
x, y = XX[ind][hysize], YY[ind][hysize]
if self.too_close(x, y, lw):
continue
return x, y, ind
ind = adist[0]
x, y = XX[ind][hysize], YY[ind][hysize]
return x, y, ind
def get_label_width(self, lev, fmt, fsize):
"""
Return the width of the label in points.
"""
if not isinstance(lev, str):
lev = self.get_text(lev, fmt)
lev, ismath = text.Text()._preprocess_math(lev)
if ismath == 'TeX':
lw, _, _ = (texmanager.TexManager()
.get_text_width_height_descent(lev, fsize))
elif ismath:
if not hasattr(self, '_mathtext_parser'):
self._mathtext_parser = mathtext.MathTextParser('bitmap')
img, _ = self._mathtext_parser.parse(lev, dpi=72,
prop=self.labelFontProps)
_, lw = np.shape(img) # at dpi=72, the units are PostScript points
else:
# width is much less than "font size"
lw = len(lev) * fsize * 0.6
return lw
def set_label_props(self, label, text, color):
"""Set the label properties - color, fontsize, text."""
label.set_text(text)
label.set_color(color)
label.set_fontproperties(self.labelFontProps)
label.set_clip_box(self.ax.bbox)
def get_text(self, lev, fmt):
"""Get the text of the label."""
if isinstance(lev, str):
return lev
else:
if isinstance(fmt, dict):
return fmt.get(lev, '%1.3f')
elif callable(fmt):
return fmt(lev)
else:
return fmt % lev
def locate_label(self, linecontour, labelwidth):
"""
Find good place to draw a label (relatively flat part of the contour).
"""
# Number of contour points
nsize = len(linecontour)
if labelwidth > 1:
xsize = int(np.ceil(nsize / labelwidth))
else:
xsize = 1
if xsize == 1:
ysize = nsize
else:
ysize = int(labelwidth)
XX = np.resize(linecontour[:, 0], (xsize, ysize))
YY = np.resize(linecontour[:, 1], (xsize, ysize))
# I might have fouled up the following:
yfirst = YY[:, :1]
ylast = YY[:, -1:]
xfirst = XX[:, :1]
xlast = XX[:, -1:]
s = (yfirst - YY) * (xlast - xfirst) - (xfirst - XX) * (ylast - yfirst)
L = np.hypot(xlast - xfirst, ylast - yfirst)
# Ignore warning that divide by zero throws, as this is a valid option
with np.errstate(divide='ignore', invalid='ignore'):
dist = np.sum(np.abs(s) / L, axis=-1)
x, y, ind = self.get_label_coords(dist, XX, YY, ysize, labelwidth)
# There must be a more efficient way...
lc = [tuple(l) for l in linecontour]
dind = lc.index((x, y))
return x, y, dind
def calc_label_rot_and_inline(self, slc, ind, lw, lc=None, spacing=5):
"""
This function calculates the appropriate label rotation given
the linecontour coordinates in screen units, the index of the
label location and the label width.
It will also break contour and calculate inlining if *lc* is
not empty (lc defaults to the empty list if None). *spacing*
is the space around the label in pixels to leave empty.
Do both of these tasks at once to avoid calculating path lengths
multiple times, which is relatively costly.
The method used here involves calculating the path length
along the contour in pixel coordinates and then looking
approximately label width / 2 away from central point to
determine rotation and then to break contour if desired.
"""
if lc is None:
lc = []
# Half the label width
hlw = lw / 2.0
# Check if closed and, if so, rotate contour so label is at edge
closed = _is_closed_polygon(slc)
if closed:
slc = np.concatenate([slc[ind:-1], slc[:ind + 1]])
if len(lc): # Rotate lc also if not empty
lc = np.concatenate([lc[ind:-1], lc[:ind + 1]])
ind = 0
# Calculate path lengths
pl = np.zeros(slc.shape[0], dtype=float)
dx = np.diff(slc, axis=0)
pl[1:] = np.cumsum(np.hypot(dx[:, 0], dx[:, 1]))
pl = pl - pl[ind]
# Use linear interpolation to get points around label
xi = np.array([-hlw, hlw])
if closed: # Look at end also for closed contours
dp = np.array([pl[-1], 0])
else:
dp = np.zeros_like(xi)
# Get angle of vector between the two ends of the label - must be
# calculated in pixel space for text rotation to work correctly.
(dx,), (dy,) = (np.diff(np.interp(dp + xi, pl, slc_col))
for slc_col in slc.T)
rotation = np.rad2deg(np.arctan2(dy, dx))
if self.rightside_up:
# Fix angle so text is never upside-down
rotation = (rotation + 90) % 180 - 90
# Break contour if desired
nlc = []
if len(lc):
# Expand range by spacing
xi = dp + xi + np.array([-spacing, spacing])
# Get (integer) indices near points of interest; use -1 as marker
# for out of bounds.
I = np.interp(xi, pl, np.arange(len(pl)), left=-1, right=-1)
I = [np.floor(I[0]).astype(int), np.ceil(I[1]).astype(int)]
if I[0] != -1:
xy1 = [np.interp(xi[0], pl, lc_col) for lc_col in lc.T]
if I[1] != -1:
xy2 = [np.interp(xi[1], pl, lc_col) for lc_col in lc.T]
# Actually break contours
if closed:
# This will remove contour if shorter than label
if all(i != -1 for i in I):
nlc.append(np.row_stack([xy2, lc[I[1]:I[0]+1], xy1]))
else:
# These will remove pieces of contour if they have length zero
if I[0] != -1:
nlc.append(np.row_stack([lc[:I[0]+1], xy1]))
if I[1] != -1:
nlc.append(np.row_stack([xy2, lc[I[1]:]]))
# The current implementation removes contours completely
# covered by labels. Uncomment line below to keep
# original contour if this is the preferred behavior.
# if not len(nlc): nlc = [ lc ]
return rotation, nlc
def _get_label_text(self, x, y, rotation):
dx, dy = self.ax.transData.inverted().transform((x, y))
t = text.Text(dx, dy, rotation=rotation,
horizontalalignment='center',
verticalalignment='center')
return t
def _get_label_clabeltext(self, x, y, rotation):
# x, y, rotation is given in pixel coordinate. Convert them to
# the data coordinate and create a label using ClabelText
# class. This way, the rotation of the clabel is along the
# contour line always.
transDataInv = self.ax.transData.inverted()
dx, dy = transDataInv.transform((x, y))
drotation = transDataInv.transform_angles(np.array([rotation]),
np.array([[x, y]]))
t = ClabelText(dx, dy, rotation=drotation[0],
horizontalalignment='center',
verticalalignment='center')
return t
def _add_label(self, t, x, y, lev, cvalue):
color = self.labelMappable.to_rgba(cvalue, alpha=self.alpha)
_text = self.get_text(lev, self.labelFmt)
self.set_label_props(t, _text, color)
self.labelTexts.append(t)
self.labelCValues.append(cvalue)
self.labelXYs.append((x, y))
# Add label to plot here - useful for manual mode label selection
self.ax.add_artist(t)
def add_label(self, x, y, rotation, lev, cvalue):
"""
Add contour label using :class:`~matplotlib.text.Text` class.
"""
t = self._get_label_text(x, y, rotation)
self._add_label(t, x, y, lev, cvalue)
def add_label_clabeltext(self, x, y, rotation, lev, cvalue):
"""
Add contour label using :class:`ClabelText` class.
"""
# x, y, rotation is given in pixel coordinate. Convert them to
# the data coordinate and create a label using ClabelText
# class. This way, the rotation of the clabel is along the
# contour line always.
t = self._get_label_clabeltext(x, y, rotation)
self._add_label(t, x, y, lev, cvalue)
def add_label_near(self, x, y, inline=True, inline_spacing=5,
transform=None):
"""
Add a label near the point (x, y). If transform is None
(default), (x, y) is in data coordinates; if transform is
False, (x, y) is in display coordinates; otherwise, the
specified transform will be used to translate (x, y) into
display coordinates.
Parameters
----------
x, y : float
The approximate location of the label.
inline : bool, default: True
If *True* remove the segment of the contour beneath the label.
inline_spacing : int, default: 5
Space in pixels to leave on each side of label when placing
inline. This spacing will be exact for labels at locations where
the contour is straight, less so for labels on curved contours.
"""
if transform is None:
transform = self.ax.transData
if transform:
x, y = transform.transform((x, y))
# find the nearest contour _in screen units_
conmin, segmin, imin, xmin, ymin = self.find_nearest_contour(
x, y, self.labelIndiceList)[:5]
# The calc_label_rot_and_inline routine requires that (xmin, ymin)
# be a vertex in the path. So, if it isn't, add a vertex here
# grab the paths from the collections
paths = self.collections[conmin].get_paths()
# grab the correct segment
active_path = paths[segmin]
# grab its vertices
lc = active_path.vertices
# sort out where the new vertex should be added data-units
xcmin = self.ax.transData.inverted().transform([xmin, ymin])
# if there isn't a vertex close enough
if not np.allclose(xcmin, lc[imin]):
# insert new data into the vertex list
lc = np.row_stack([lc[:imin], xcmin, lc[imin:]])
# replace the path with the new one
paths[segmin] = mpath.Path(lc)
# Get index of nearest level in subset of levels used for labeling
lmin = self.labelIndiceList.index(conmin)
# Coordinates of contour
paths = self.collections[conmin].get_paths()
lc = paths[segmin].vertices
# In pixel/screen space
slc = self.ax.transData.transform(lc)
# Get label width for rotating labels and breaking contours
lw = self.get_label_width(self.labelLevelList[lmin],
self.labelFmt, self.labelFontSizeList[lmin])
# lw is in points.
lw *= self.ax.figure.dpi / 72.0 # scale to screen coordinates
# now lw in pixels
# Figure out label rotation.
if inline:
lcarg = lc
else:
lcarg = None
rotation, nlc = self.calc_label_rot_and_inline(
slc, imin, lw, lcarg,
inline_spacing)
self.add_label(xmin, ymin, rotation, self.labelLevelList[lmin],
self.labelCValueList[lmin])
if inline:
# Remove old, not looping over paths so we can do this up front
paths.pop(segmin)
# Add paths if not empty or single point
for n in nlc:
if len(n) > 1:
paths.append(mpath.Path(n))
def pop_label(self, index=-1):
"""Defaults to removing last label, but any index can be supplied"""
self.labelCValues.pop(index)
t = self.labelTexts.pop(index)
t.remove()
def labels(self, inline, inline_spacing):
if self._use_clabeltext:
add_label = self.add_label_clabeltext
else:
add_label = self.add_label
for icon, lev, fsize, cvalue in zip(
self.labelIndiceList, self.labelLevelList,
self.labelFontSizeList, self.labelCValueList):
con = self.collections[icon]
trans = con.get_transform()
lw = self.get_label_width(lev, self.labelFmt, fsize)
lw *= self.ax.figure.dpi / 72.0 # scale to screen coordinates
additions = []
paths = con.get_paths()
for segNum, linepath in enumerate(paths):
lc = linepath.vertices # Line contour
slc0 = trans.transform(lc) # Line contour in screen coords
# For closed polygons, add extra point to avoid division by
# zero in print_label and locate_label. Other than these
# functions, this is not necessary and should probably be
# eventually removed.
if _is_closed_polygon(lc):
slc = np.row_stack([slc0, slc0[1:2]])
else:
slc = slc0
# Check if long enough for a label
if self.print_label(slc, lw):
x, y, ind = self.locate_label(slc, lw)
if inline:
lcarg = lc
else:
lcarg = None
rotation, new = self.calc_label_rot_and_inline(
slc0, ind, lw, lcarg,
inline_spacing)
# Actually add the label
add_label(x, y, rotation, lev, cvalue)
# If inline, add new contours
if inline:
for n in new:
# Add path if not empty or single point
if len(n) > 1:
additions.append(mpath.Path(n))
else: # If not adding label, keep old path
additions.append(linepath)
# After looping over all segments on a contour, replace old paths
# by new ones if inlining.
if inline:
paths[:] = additions
def _find_closest_point_on_leg(p1, p2, p0):
"""Find the closest point to p0 on line segment connecting p1 and p2."""
# handle degenerate case
if np.all(p2 == p1):
d = np.sum((p0 - p1)**2)
return d, p1
d21 = p2 - p1
d01 = p0 - p1
# project on to line segment to find closest point
proj = np.dot(d01, d21) / np.dot(d21, d21)
if proj < 0:
proj = 0
if proj > 1:
proj = 1
pc = p1 + proj * d21
# find squared distance
d = np.sum((pc-p0)**2)
return d, pc
def _is_closed_polygon(X):
"""
Return whether first and last object in a sequence are the same. These are
presumably coordinates on a polygonal curve, in which case this function
tests if that curve is closed.
"""
return np.all(X[0] == X[-1])
def _find_closest_point_on_path(lc, point):
"""
Parameters
----------
lc : coordinates of vertices
point : coordinates of test point
"""
# find index of closest vertex for this segment
ds = np.sum((lc - point[None, :])**2, 1)
imin = np.argmin(ds)
dmin = np.inf
xcmin = None
legmin = (None, None)
closed = _is_closed_polygon(lc)
# build list of legs before and after this vertex
legs = []
if imin > 0 or closed:
legs.append(((imin-1) % len(lc), imin))
if imin < len(lc) - 1 or closed:
legs.append((imin, (imin+1) % len(lc)))
for leg in legs:
d, xc = _find_closest_point_on_leg(lc[leg[0]], lc[leg[1]], point)
if d < dmin:
dmin = d
xcmin = xc
legmin = leg
return (dmin, xcmin, legmin)
class ContourSet(cm.ScalarMappable, ContourLabeler):
"""
Store a set of contour lines or filled regions.
User-callable method: `~.Axes.clabel`
Parameters
----------
ax : `~.axes.Axes`
levels : [level0, level1, ..., leveln]
A list of floating point numbers indicating the contour levels.
allsegs : [level0segs, level1segs, ...]
List of all the polygon segments for all the *levels*.
For contour lines ``len(allsegs) == len(levels)``, and for
filled contour regions ``len(allsegs) = len(levels)-1``. The lists
should look like ::
level0segs = [polygon0, polygon1, ...]
polygon0 = [[x0, y0], [x1, y1], ...]
allkinds : ``None`` or [level0kinds, level1kinds, ...]
Optional list of all the polygon vertex kinds (code types), as
described and used in Path. This is used to allow multiply-
connected paths such as holes within filled polygons.
If not ``None``, ``len(allkinds) == len(allsegs)``. The lists
should look like ::
level0kinds = [polygon0kinds, ...]
polygon0kinds = [vertexcode0, vertexcode1, ...]
If *allkinds* is not ``None``, usually all polygons for a
particular contour level are grouped together so that
``level0segs = [polygon0]`` and ``level0kinds = [polygon0kinds]``.
**kwargs
Keyword arguments are as described in the docstring of
`~.Axes.contour`.
Attributes
----------
ax
The axes object in which the contours are drawn.
collections
A silent_list of LineCollections or PolyCollections.
levels
Contour levels.
layers
Same as levels for line contours; half-way between
levels for filled contours. See :meth:`_process_colors`.
"""
def __init__(self, ax, *args,
levels=None, filled=False, linewidths=None, linestyles=None,
alpha=None, origin=None, extent=None,
cmap=None, colors=None, norm=None, vmin=None, vmax=None,
extend='neither', antialiased=None,
**kwargs):
"""
Draw contour lines or filled regions, depending on
whether keyword arg *filled* is ``False`` (default) or ``True``.
Call signature::
ContourSet(ax, levels, allsegs, [allkinds], **kwargs)
Parameters
----------
ax : `~.axes.Axes`
The `~.axes.Axes` object to draw on.
levels : [level0, level1, ..., leveln]
A list of floating point numbers indicating the contour
levels.
allsegs : [level0segs, level1segs, ...]
List of all the polygon segments for all the *levels*.
For contour lines ``len(allsegs) == len(levels)``, and for
filled contour regions ``len(allsegs) = len(levels)-1``. The lists
should look like ::
level0segs = [polygon0, polygon1, ...]
polygon0 = [[x0, y0], [x1, y1], ...]
allkinds : [level0kinds, level1kinds, ...], optional
Optional list of all the polygon vertex kinds (code types), as
described and used in Path. This is used to allow multiply-
connected paths such as holes within filled polygons.
If not ``None``, ``len(allkinds) == len(allsegs)``. The lists
should look like ::
level0kinds = [polygon0kinds, ...]
polygon0kinds = [vertexcode0, vertexcode1, ...]
If *allkinds* is not ``None``, usually all polygons for a
particular contour level are grouped together so that
``level0segs = [polygon0]`` and ``level0kinds = [polygon0kinds]``.
**kwargs
Keyword arguments are as described in the docstring of
`~.Axes.contour`.
"""
self.ax = ax
self.levels = levels
self.filled = filled
self.linewidths = linewidths
self.linestyles = linestyles
self.hatches = kwargs.pop('hatches', [None])
self.alpha = alpha
self.origin = origin
self.extent = extent
self.colors = colors
self.extend = extend
self.antialiased = antialiased
if self.antialiased is None and self.filled:
# Eliminate artifacts; we are not stroking the boundaries.
self.antialiased = False
# The default for line contours will be taken from the
# LineCollection default, which uses :rc:`lines.antialiased`.
self.nchunk = kwargs.pop('nchunk', 0)
self.locator = kwargs.pop('locator', None)
if (isinstance(norm, mcolors.LogNorm)
or isinstance(self.locator, ticker.LogLocator)):
self.logscale = True
if norm is None:
norm = mcolors.LogNorm()
else:
self.logscale = False
cbook._check_in_list([None, 'lower', 'upper', 'image'], origin=origin)
if self.extent is not None and len(self.extent) != 4:
raise ValueError(
"If given, 'extent' must be None or (x0, x1, y0, y1)")
if self.colors is not None and cmap is not None:
raise ValueError('Either colors or cmap must be None')
if self.origin == 'image':
self.origin = mpl.rcParams['image.origin']
self._transform = kwargs.pop('transform', None)
kwargs = self._process_args(*args, **kwargs)
self._process_levels()
if self.colors is not None:
ncolors = len(self.levels)
if self.filled:
ncolors -= 1
i0 = 0
# Handle the case where colors are given for the extended
# parts of the contour.
extend_min = self.extend in ['min', 'both']
extend_max = self.extend in ['max', 'both']
use_set_under_over = False
# if we are extending the lower end, and we've been given enough
# colors then skip the first color in the resulting cmap. For the
# extend_max case we don't need to worry about passing more colors
# than ncolors as ListedColormap will clip.
total_levels = ncolors + int(extend_min) + int(extend_max)
if len(self.colors) == total_levels and (extend_min or extend_max):
use_set_under_over = True
if extend_min:
i0 = 1
cmap = mcolors.ListedColormap(self.colors[i0:None], N=ncolors)
if use_set_under_over:
if extend_min:
cmap.set_under(self.colors[0])
if extend_max:
cmap.set_over(self.colors[-1])
if self.filled:
self.collections = cbook.silent_list('mcoll.PathCollection')
else:
self.collections = cbook.silent_list('mcoll.LineCollection')
# label lists must be initialized here
self.labelTexts = []
self.labelCValues = []
kw = {'cmap': cmap}
if norm is not None:
kw['norm'] = norm
# sets self.cmap, norm if needed;
cm.ScalarMappable.__init__(self, **kw)
if vmin is not None:
self.norm.vmin = vmin
if vmax is not None:
self.norm.vmax = vmax
self._process_colors()
self.allsegs, self.allkinds = self._get_allsegs_and_allkinds()
if self.filled:
if self.linewidths is not None:
cbook._warn_external('linewidths is ignored by contourf')
# Lower and upper contour levels.
lowers, uppers = self._get_lowers_and_uppers()
# Ensure allkinds can be zipped below.
if self.allkinds is None:
self.allkinds = [None] * len(self.allsegs)
# Default zorder taken from Collection
zorder = kwargs.pop('zorder', 1)
for level, level_upper, segs, kinds in \
zip(lowers, uppers, self.allsegs, self.allkinds):
paths = self._make_paths(segs, kinds)
col = mcoll.PathCollection(
paths,
antialiaseds=(self.antialiased,),
edgecolors='none',
alpha=self.alpha,
transform=self.get_transform(),
zorder=zorder)
self.ax.add_collection(col, autolim=False)
self.collections.append(col)
else:
tlinewidths = self._process_linewidths()
self.tlinewidths = tlinewidths
tlinestyles = self._process_linestyles()
aa = self.antialiased
if aa is not None:
aa = (self.antialiased,)
# Default zorder taken from LineCollection
zorder = kwargs.pop('zorder', 2)
for level, width, lstyle, segs in \
zip(self.levels, tlinewidths, tlinestyles, self.allsegs):
col = mcoll.LineCollection(
segs,
antialiaseds=aa,
linewidths=width,
linestyles=[lstyle],
alpha=self.alpha,
transform=self.get_transform(),
zorder=zorder)
col.set_label('_nolegend_')
self.ax.add_collection(col, autolim=False)
self.collections.append(col)
for col in self.collections:
col.sticky_edges.x[:] = [self._mins[0], self._maxs[0]]
col.sticky_edges.y[:] = [self._mins[1], self._maxs[1]]
self.ax.update_datalim([self._mins, self._maxs])
self.ax.autoscale_view(tight=True)
self.changed() # set the colors
if kwargs:
s = ", ".join(map(repr, kwargs))
cbook._warn_external('The following kwargs were not used by '
'contour: ' + s)
def get_transform(self):
"""
Return the :class:`~matplotlib.transforms.Transform`
instance used by this ContourSet.
"""
if self._transform is None:
self._transform = self.ax.transData
elif (not isinstance(self._transform, mtransforms.Transform)
and hasattr(self._transform, '_as_mpl_transform')):
self._transform = self._transform._as_mpl_transform(self.ax)
return self._transform
def __getstate__(self):
state = self.__dict__.copy()
# the C object _contour_generator cannot currently be pickled. This
# isn't a big issue as it is not actually used once the contour has
# been calculated.
state['_contour_generator'] = None
return state
def legend_elements(self, variable_name='x', str_format=str):
"""
Return a list of artists and labels suitable for passing through
to :func:`plt.legend` which represent this ContourSet.
The labels have the form "0 < x <= 1" stating the data ranges which
the artists represent.
Parameters
----------
variable_name : str
The string used inside the inequality used on the labels.
str_format : function: float -> str
Function used to format the numbers in the labels.
Returns
-------
artists : List[`.Artist`]
A list of the artists.
labels : List[str]
A list of the labels.
"""
artists = []
labels = []
if self.filled:
lowers, uppers = self._get_lowers_and_uppers()
n_levels = len(self.collections)
for i, (collection, lower, upper) in enumerate(
zip(self.collections, lowers, uppers)):
patch = mpatches.Rectangle(
(0, 0), 1, 1,
facecolor=collection.get_facecolor()[0],
hatch=collection.get_hatch(),
alpha=collection.get_alpha())
artists.append(patch)
lower = str_format(lower)
upper = str_format(upper)
if i == 0 and self.extend in ('min', 'both'):
labels.append(fr'${variable_name} \leq {lower}s$')
elif i == n_levels - 1 and self.extend in ('max', 'both'):
labels.append(fr'${variable_name} > {upper}s$')
else: