class_docstr: 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 `~.Spine.set_position` for more information.
  
  The default position is ``('outward', 0)``.
  
  Spines are subclasses of `.Patch`, and inherit much of their behavior.
  
  Spines draw a line, a circle, or an arc depending on if
  `~.Spine.set_patch_line`, `~.Spine.set_patch_circle`, or
  `~.Spine.set_patch_arc` has been called. Line-like is the default.
  
  For examples see :ref:`spines_examples`.
class_docstr_tok: ["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","`","~.Spine.set_position","`","for","more","information",".","The","default","position","is","``","(","'outward","'",",","0",")","``",".","Spines","are","subclasses","of","`",".Patch","`",",","and","inherit","much","of","their","behavior",".","Spines","draw","a","line",",","a","circle",",","or","an","arc","depending","on","if","`","~.Spine.set_patch_line","`",",","`","~.Spine.set_patch_circle","`",",","or","`","~.Spine.set_patch_arc","`","has","been","called",".","Line-like","is","the","default",".","For","examples","see",":","ref",":","`","spines_examples","`","."]
docstr: Return the spine transform.
docstr_tok: ["Return","the","spine","transform","."]
code: def get_spine_transform(self):
      """Return the spine transform."""
      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
      _api.check_in_list(
          ["axes", "outward", "data"], position_type=position_type
      )
      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(
              f"unknown spine spine_type: {self.spine_type!r}"
          )
  
      if position_type == "outward":
          if amount == 0:  # short circuit commonest case
              return base_transform
          else:
              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_dots = amount * np.array(offset_vec) / 72
              return base_transform + mtransforms.ScaledTranslation(
                  *offset_dots, self.figure.dpi_scale_trans
              )
      elif position_type == "axes":
          if self.spine_type in ["left", "right"]:
              # keep y unchanged, fix x at amount
              return (
                  mtransforms.Affine2D.from_values(
                      0, 0, 0, 1, amount, 0
                  )
                  + base_transform
              )
          elif self.spine_type in ["bottom", "top"]:
              # keep x unchanged, fix y at amount
              return (
                  mtransforms.Affine2D.from_values(
                      1, 0, 0, 0, 0, amount
                  )
                  + base_transform
              )
      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"):
              return mtransforms.blended_transform_factory(
                  mtransforms.Affine2D().translate(amount, 0)
                  + self.axes.transData,
                  self.axes.transData,
              )
          elif self.spine_type in ("bottom", "top"):
              return mtransforms.blended_transform_factory(
                  self.axes.transData,
                  mtransforms.Affine2D().translate(0, amount)
                  + self.axes.transData,
              )
  
imports: from collections.abc import MutableMapping
  import functools
  import numpy
  import matplotlib
  from matplotlib import _api, _docstring
  from matplotlib.artist import allow_rasterization
  import matplotlib.transforms
  import matplotlib.patches
  import matplotlib.path
label_desc: Use image node_id 18 for calling the Spine obj's underlying member method code with example usage: obj.get_spine_transform() and returns: base_transform, unknown, unknown, unknown, mtransforms, mtransforms