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Version 3.0.2
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Source code for matplotlib.spines

import warnings

import numpy as np

import matplotlib
from matplotlib import docstring, rcParams
from matplotlib.artist import allow_rasterization
import matplotlib.transforms as mtransforms
import matplotlib.patches as mpatches
import matplotlib.path as mpath


[docs]class Spine(mpatches.Patch): """an axis spine -- the line noting the data area boundaries Spines are the lines connecting the axis tick marks and noting the boundaries of the data area. They can be placed at arbitrary positions. See function:`~matplotlib.spines.Spine.set_position` for more information. The default position is ``('outward',0)``. Spines are subclasses of class:`~matplotlib.patches.Patch`, and inherit much of their behavior. Spines draw a line, a circle, or an arc depending if function:`~matplotlib.spines.Spine.set_patch_line`, function:`~matplotlib.spines.Spine.set_patch_circle`, or function:`~matplotlib.spines.Spine.set_patch_arc` has been called. Line-like is the default. """ def __str__(self): return "Spine" @docstring.dedent_interpd def __init__(self, axes, spine_type, path, **kwargs): """ - *axes* : the Axes instance containing the spine - *spine_type* : a string specifying the spine type - *path* : the path instance used to draw the spine Valid kwargs are: %(Patch)s """ super().__init__(**kwargs) self.axes = axes self.set_figure(self.axes.figure) self.spine_type = spine_type self.set_facecolor('none') self.set_edgecolor(rcParams['axes.edgecolor']) self.set_linewidth(rcParams['axes.linewidth']) self.set_capstyle('projecting') self.axis = None self.set_zorder(2.5) self.set_transform(self.axes.transData) # default transform self._bounds = None # default bounds self._smart_bounds = False # Defer initial position determination. (Not much support for # non-rectangular axes is currently implemented, and this lets # them pass through the spines machinery without errors.) self._position = None if not isinstance(path, matplotlib.path.Path): raise ValueError( "'path' must be an instance of 'matplotlib.path.Path'") self._path = path # To support drawing both linear and circular spines, this # class implements Patch behavior three ways. If # self._patch_type == 'line', behave like a mpatches.PathPatch # instance. If self._patch_type == 'circle', behave like a # mpatches.Ellipse instance. If self._patch_type == 'arc', behave like # a mpatches.Arc instance. self._patch_type = 'line' # Behavior copied from mpatches.Ellipse: # Note: This cannot be calculated until this is added to an Axes self._patch_transform = mtransforms.IdentityTransform()
[docs] def set_smart_bounds(self, value): """set the spine and associated axis to have smart bounds""" self._smart_bounds = value # also set the axis if possible if self.spine_type in ('left', 'right'): self.axes.yaxis.set_smart_bounds(value) elif self.spine_type in ('top', 'bottom'): self.axes.xaxis.set_smart_bounds(value) self.stale = True
[docs] def get_smart_bounds(self): """get whether the spine has smart bounds""" return self._smart_bounds
[docs] def set_patch_arc(self, center, radius, theta1, theta2): """set the spine to be arc-like""" self._patch_type = 'arc' self._center = center self._width = radius * 2 self._height = radius * 2 self._theta1 = theta1 self._theta2 = theta2 self._path = mpath.Path.arc(theta1, theta2) # arc drawn on axes transform self.set_transform(self.axes.transAxes) self.stale = True
[docs] def set_patch_circle(self, center, radius): """set the spine to be circular""" self._patch_type = 'circle' self._center = center self._width = radius * 2 self._height = radius * 2 # circle drawn on axes transform self.set_transform(self.axes.transAxes) self.stale = True
[docs] def set_patch_line(self): """set the spine to be linear""" self._patch_type = 'line' self.stale = True
# Behavior copied from mpatches.Ellipse: def _recompute_transform(self): """NOTE: This cannot be called until after this has been added to an Axes, otherwise unit conversion will fail. This makes it very important to call the accessor method and not directly access the transformation member variable. """ assert self._patch_type in ('arc', 'circle') center = (self.convert_xunits(self._center[0]), self.convert_yunits(self._center[1])) width = self.convert_xunits(self._width) height = self.convert_yunits(self._height) self._patch_transform = mtransforms.Affine2D() \ .scale(width * 0.5, height * 0.5) \ .translate(*center)
[docs] def get_patch_transform(self): if self._patch_type in ('arc', 'circle'): self._recompute_transform() return self._patch_transform else: return super().get_patch_transform()
[docs] def get_window_extent(self, renderer=None): # make sure the location is updated so that transforms etc are # correct: self._adjust_location() return super().get_window_extent(renderer=renderer)
[docs] def get_path(self): return self._path
def _ensure_position_is_set(self): if self._position is None: # default position self._position = ('outward', 0.0) # in points self.set_position(self._position)
[docs] def register_axis(self, axis): """register an axis An axis should be registered with its corresponding spine from the Axes instance. This allows the spine to clear any axis properties when needed. """ self.axis = axis if self.axis is not None: self.axis.cla() self.stale = True
[docs] def cla(self): """Clear the current spine""" self._position = None # clear position if self.axis is not None: self.axis.cla()
[docs] def is_frame_like(self): """return True if directly on axes frame This is useful for determining if a spine is the edge of an old style MPL plot. If so, this function will return True. """ self._ensure_position_is_set() position = self._position if isinstance(position, str): if position == 'center': position = ('axes', 0.5) elif position == 'zero': position = ('data', 0) if len(position) != 2: raise ValueError("position should be 2-tuple") position_type, amount = position if position_type == 'outward' and amount == 0: return True else: return False
def _adjust_location(self): """automatically set spine bounds to the view interval""" if self.spine_type == 'circle': return if self._bounds is None: if self.spine_type in ('left', 'right'): low, high = self.axes.viewLim.intervaly elif self.spine_type in ('top', 'bottom'): low, high = self.axes.viewLim.intervalx else: raise ValueError('unknown spine spine_type: %s' % self.spine_type) if self._smart_bounds: # attempt to set bounds in sophisticated way # handle inverted limits viewlim_low, viewlim_high = sorted([low, high]) if self.spine_type in ('left', 'right'): datalim_low, datalim_high = self.axes.dataLim.intervaly ticks = self.axes.get_yticks() elif self.spine_type in ('top', 'bottom'): datalim_low, datalim_high = self.axes.dataLim.intervalx ticks = self.axes.get_xticks() # handle inverted limits ticks = np.sort(ticks) datalim_low, datalim_high = sorted([datalim_low, datalim_high]) if datalim_low < viewlim_low: # Data extends past view. Clip line to view. low = viewlim_low else: # Data ends before view ends. cond = (ticks <= datalim_low) & (ticks >= viewlim_low) tickvals = ticks[cond] if len(tickvals): # A tick is less than or equal to lowest data point. low = tickvals[-1] else: # No tick is available low = datalim_low low = max(low, viewlim_low) if datalim_high > viewlim_high: # Data extends past view. Clip line to view. high = viewlim_high else: # Data ends before view ends. cond = (ticks >= datalim_high) & (ticks <= viewlim_high) tickvals = ticks[cond] if len(tickvals): # A tick is greater than or equal to highest data # point. high = tickvals[0] else: # No tick is available high = datalim_high high = min(high, viewlim_high) else: low, high = self._bounds if self._patch_type == 'arc': if self.spine_type in ('bottom', 'top'): try: direction = self.axes.get_theta_direction() except AttributeError: direction = 1 try: offset = self.axes.get_theta_offset() except AttributeError: offset = 0 low = low * direction + offset high = high * direction + offset if low > high: low, high = high, low self._path = mpath.Path.arc(np.rad2deg(low), np.rad2deg(high)) if self.spine_type == 'bottom': rmin, rmax = self.axes.viewLim.intervaly try: rorigin = self.axes.get_rorigin() except AttributeError: rorigin = rmin scaled_diameter = (rmin - rorigin) / (rmax - rorigin) self._height = scaled_diameter self._width = scaled_diameter else: raise ValueError('unable to set bounds for spine "%s"' % self.spine_type) else: v1 = self._path.vertices assert v1.shape == (2, 2), 'unexpected vertices shape' if self.spine_type in ['left', 'right']: v1[0, 1] = low v1[1, 1] = high elif self.spine_type in ['bottom', 'top']: v1[0, 0] = low v1[1, 0] = high else: raise ValueError('unable to set bounds for spine "%s"' % self.spine_type)
[docs] @allow_rasterization def draw(self, renderer): self._adjust_location() ret = super().draw(renderer) self.stale = False return ret
def _calc_offset_transform(self): """calculate the offset transform performed by the spine""" self._ensure_position_is_set() position = self._position if isinstance(position, str): if position == 'center': position = ('axes', 0.5) elif position == 'zero': position = ('data', 0) assert len(position) == 2, "position should be 2-tuple" position_type, amount = position assert position_type in ('axes', 'outward', 'data') if position_type == 'outward': if amount == 0: # short circuit commonest case self._spine_transform = ('identity', mtransforms.IdentityTransform()) elif self.spine_type in ['left', 'right', 'top', 'bottom']: offset_vec = {'left': (-1, 0), 'right': (1, 0), 'bottom': (0, -1), 'top': (0, 1), }[self.spine_type] # calculate x and y offset in dots offset_x = amount * offset_vec[0] / 72.0 offset_y = amount * offset_vec[1] / 72.0 self._spine_transform = ('post', mtransforms.ScaledTranslation( offset_x, offset_y, self.figure.dpi_scale_trans)) else: warnings.warn('unknown spine type "%s": no spine ' 'offset performed' % self.spine_type) self._spine_transform = ('identity', mtransforms.IdentityTransform()) elif position_type == 'axes': if self.spine_type in ('left', 'right'): self._spine_transform = ('pre', mtransforms.Affine2D.from_values( # keep y unchanged, fix x at # amount 0, 0, 0, 1, amount, 0)) elif self.spine_type in ('bottom', 'top'): self._spine_transform = ('pre', mtransforms.Affine2D.from_values( # keep x unchanged, fix y at # amount 1, 0, 0, 0, 0, amount)) else: warnings.warn('unknown spine type "%s": no spine ' 'offset performed' % self.spine_type) self._spine_transform = ('identity', mtransforms.IdentityTransform()) elif position_type == 'data': if self.spine_type in ('right', 'top'): # The right and top spines have a default position of 1 in # axes coordinates. When specifying the position in data # coordinates, we need to calculate the position relative to 0. amount -= 1 if self.spine_type in ('left', 'right'): self._spine_transform = ('data', mtransforms.Affine2D().translate( amount, 0)) elif self.spine_type in ('bottom', 'top'): self._spine_transform = ('data', mtransforms.Affine2D().translate( 0, amount)) else: warnings.warn('unknown spine type "%s": no spine ' 'offset performed' % self.spine_type) self._spine_transform = ('identity', mtransforms.IdentityTransform())
[docs] def set_position(self, position): """set the position of the spine Spine position is specified by a 2 tuple of (position type, amount). The position types are: * 'outward' : place the spine out from the data area by the specified number of points. (Negative values specify placing the spine inward.) * 'axes' : place the spine at the specified Axes coordinate (from 0.0-1.0). * 'data' : place the spine at the specified data coordinate. Additionally, shorthand notations define a special positions: * 'center' -> ('axes',0.5) * 'zero' -> ('data', 0.0) """ if position in ('center', 'zero'): # special positions pass else: if len(position) != 2: raise ValueError("position should be 'center' or 2-tuple") if position[0] not in ['outward', 'axes', 'data']: raise ValueError("position[0] should be one of 'outward', " "'axes', or 'data' ") self._position = position self._calc_offset_transform() self.set_transform(self.get_spine_transform()) if self.axis is not None: self.axis.reset_ticks() self.stale = True
[docs] def get_position(self): """get the spine position""" self._ensure_position_is_set() return self._position
[docs] def get_spine_transform(self): """get the spine transform""" self._ensure_position_is_set() what, how = self._spine_transform if what == 'data': # special case data based spine locations data_xform = self.axes.transScale + \ (how + self.axes.transLimits + self.axes.transAxes) if self.spine_type in ['left', 'right']: result = mtransforms.blended_transform_factory( data_xform, self.axes.transData) elif self.spine_type in ['top', 'bottom']: result = mtransforms.blended_transform_factory( self.axes.transData, data_xform) else: raise ValueError('unknown spine spine_type: %s' % self.spine_type) return result if self.spine_type in ['left', 'right']: base_transform = self.axes.get_yaxis_transform(which='grid') elif self.spine_type in ['top', 'bottom']: base_transform = self.axes.get_xaxis_transform(which='grid') else: raise ValueError('unknown spine spine_type: %s' % self.spine_type) if what == 'identity': return base_transform elif what == 'post': return base_transform + how elif what == 'pre': return how + base_transform else: raise ValueError("unknown spine_transform type: %s" % what)
[docs] def set_bounds(self, low, high): """Set the bounds of the spine.""" if self.spine_type == 'circle': raise ValueError( 'set_bounds() method incompatible with circular spines') self._bounds = (low, high) self.stale = True
[docs] def get_bounds(self): """Get the bounds of the spine.""" return self._bounds
[docs] @classmethod def linear_spine(cls, axes, spine_type, **kwargs): """ (staticmethod) Returns a linear :class:`Spine`. """ # all values of 0.999 get replaced upon call to set_bounds() if spine_type == 'left': path = mpath.Path([(0.0, 0.999), (0.0, 0.999)]) elif spine_type == 'right': path = mpath.Path([(1.0, 0.999), (1.0, 0.999)]) elif spine_type == 'bottom': path = mpath.Path([(0.999, 0.0), (0.999, 0.0)]) elif spine_type == 'top': path = mpath.Path([(0.999, 1.0), (0.999, 1.0)]) else: raise ValueError('unable to make path for spine "%s"' % spine_type) result = cls(axes, spine_type, path, **kwargs) result.set_visible(rcParams['axes.spines.{0}'.format(spine_type)]) return result
[docs] @classmethod def arc_spine(cls, axes, spine_type, center, radius, theta1, theta2, **kwargs): """ (classmethod) Returns an arc :class:`Spine`. """ path = mpath.Path.arc(theta1, theta2) result = cls(axes, spine_type, path, **kwargs) result.set_patch_arc(center, radius, theta1, theta2) return result
[docs] @classmethod def circular_spine(cls, axes, center, radius, **kwargs): """ (staticmethod) Returns a circular :class:`Spine`. """ path = mpath.Path.unit_circle() spine_type = 'circle' result = cls(axes, spine_type, path, **kwargs) result.set_patch_circle(center, radius) return result
[docs] def set_color(self, c): """ Set the edgecolor. Parameters ---------- c : color or sequence of rgba tuples .. seealso:: :meth:`set_facecolor`, :meth:`set_edgecolor` For setting the edge or face color individually. """ # The facecolor of a spine is always 'none' by default -- let # the user change it manually if desired. self.set_edgecolor(c) self.stale = True