content: """
  The OffsetBox is a simple container artist. The child artist are meant
  to be drawn at a relative position to its parent.  The [VH]Packer,
  DrawingArea and TextArea are derived from the OffsetBox.
  
  The [VH]Packer automatically adjust the relative postisions of their
  children, which should be instances of the OffsetBox. This is used to
  align similar artists together, e.g., in legend.
  
  The DrawingArea can contain any Artist as a child. The
  DrawingArea has a fixed width and height. The position of children
  relative to the parent is fixed.  The TextArea is contains a single
  Text instance. The width and height of the TextArea instance is the
  width and height of the its child text.
  """
  
  from __future__ import (absolute_import, division, print_function,
                          unicode_literals)
  
  import six
  from six.moves import xrange, zip
  
  import warnings
  import matplotlib.transforms as mtransforms
  import matplotlib.artist as martist
  import matplotlib.text as mtext
  import matplotlib.path as mpath
  import numpy as np
  from matplotlib.transforms import Bbox, BboxBase, TransformedBbox
  
  from matplotlib.font_manager import FontProperties
  from matplotlib.patches import FancyBboxPatch, FancyArrowPatch
  from matplotlib import rcParams
  
  from matplotlib import docstring
  
  #from bboximage import BboxImage
  from matplotlib.image import BboxImage
  
  from matplotlib.patches import bbox_artist as mbbox_artist
  from matplotlib.text import _AnnotationBase
  
  
  DEBUG = False
  
  
  # for debuging use
  def bbox_artist(*args, **kwargs):
      if DEBUG:
          mbbox_artist(*args, **kwargs)
  
  # _get_packed_offsets() and _get_aligned_offsets() are coded assuming
  # that we are packing boxes horizontally. But same function will be
  # used with vertical packing.
  
  
  def _get_packed_offsets(wd_list, total, sep, mode="fixed"):
      """
      Geiven a list of (width, xdescent) of each boxes, calculate the
      total width and the x-offset positions of each items according to
      *mode*. xdescent is analagous to the usual descent, but along the
      x-direction. xdescent values are currently ignored.
  
      *wd_list* : list of (width, xdescent) of boxes to be packed.
      *sep* : spacing between boxes
      *total* : Intended total length. None if not used.
      *mode* : packing mode. 'fixed', 'expand', or 'equal'.
      """
  
      w_list, d_list = list(zip(*wd_list))
      # d_list is currently not used.
  
      if mode == "fixed":
          offsets_ = np.add.accumulate([0] + [w + sep for w in w_list])
          offsets = offsets_[:-1]
  
          if total is None:
              total = offsets_[-1] - sep
  
          return total, offsets
  
      elif mode == "expand":
          if len(w_list) > 1:
              sep = (total - sum(w_list)) / (len(w_list) - 1.)
          else:
              sep = 0.
          offsets_ = np.add.accumulate([0] + [w + sep for w in w_list])
          offsets = offsets_[:-1]
  
          return total, offsets
  
      elif mode == "equal":
          maxh = max(w_list)
          if total is None:
              total = (maxh + sep) * len(w_list)
          else:
              sep = float(total) / (len(w_list)) - maxh
  
          offsets = np.array([(maxh + sep) * i for i in range(len(w_list))])
  
          return total, offsets
  
      else:
          raise ValueError("Unknown mode : %s" % (mode,))
  
  
  def _get_aligned_offsets(hd_list, height, align="baseline"):
      """
      Given a list of (height, descent) of each boxes, align the boxes
      with *align* and calculate the y-offsets of each boxes.
      total width and the offset positions of each items according to
      *mode*. xdescent is analogous to the usual descent, but along the
      x-direction. xdescent values are currently ignored.
  
      *hd_list* : list of (width, xdescent) of boxes to be aligned.
      *sep* : spacing between boxes
      *height* : Intended total length. None if not used.
      *align* : align mode. 'baseline', 'top', 'bottom', or 'center'.
      """
  
      if height is None:
          height = max([h for h, d in hd_list])
  
      if align == "baseline":
          height_descent = max([h - d for h, d in hd_list])
          descent = max([d for h, d in hd_list])
          height = height_descent + descent
          offsets = [0. for h, d in hd_list]
      elif align in ["left", "top"]:
          descent = 0.
          offsets = [d for h, d in hd_list]
      elif align in ["right", "bottom"]:
          descent = 0.
          offsets = [height - h + d for h, d in hd_list]
      elif align == "center":
          descent = 0.
          offsets = [(height - h) * .5 + d for h, d in hd_list]
      else:
          raise ValueError("Unknown Align mode : %s" % (align,))
  
      return height, descent, offsets
  
  
  class OffsetBox(martist.Artist):
      """
      The OffsetBox is a simple container artist. The child artist are meant
      to be drawn at a relative position to its parent.
      """
      def __init__(self, *args, **kwargs):
  
          super(OffsetBox, self).__init__(*args, **kwargs)
  
          # Clipping has not been implemented in the OffesetBox family, so
          # disable the clip flag for consistency. It can always be turned back
          # on to zero effect.
          self.set_clip_on(False)
  
          self._children = []
          self._offset = (0, 0)
  
      def __getstate__(self):
          state = martist.Artist.__getstate__(self)
  
          # pickle cannot save instancemethods, so handle them here
          from .cbook import _InstanceMethodPickler
          import inspect
  
          offset = state['_offset']
          if inspect.ismethod(offset):
              state['_offset'] = _InstanceMethodPickler(offset)
          return state
  
      def __setstate__(self, state):
          self.__dict__ = state
          from .cbook import _InstanceMethodPickler
          if isinstance(self._offset, _InstanceMethodPickler):
              self._offset = self._offset.get_instancemethod()
          self.stale = True
  
      def set_figure(self, fig):
          """
          Set the figure
  
          accepts a class:`~matplotlib.figure.Figure` instance
          """
          martist.Artist.set_figure(self, fig)
          for c in self.get_children():
              c.set_figure(fig)
  
      @martist.Artist.axes.setter
      def axes(self, ax):
          # TODO deal with this better
          martist.Artist.axes.fset(self, ax)
          for c in self.get_children():
              if c is not None:
                  c.axes = ax
  
      def contains(self, mouseevent):
          for c in self.get_children():
              a, b = c.contains(mouseevent)
              if a:
                  return a, b
          return False, {}
  
      def set_offset(self, xy):
          """
          Set the offset
  
          accepts x, y, tuple, or a callable object.
          """
          self._offset = xy
          self.stale = True
  
      def get_offset(self, width, height, xdescent, ydescent, renderer):
          """
          Get the offset
  
          accepts extent of the box
          """
          if six.callable(self._offset):
              return self._offset(width, height, xdescent, ydescent, renderer)
          else:
              return self._offset
  
      def set_width(self, width):
          """
          Set the width
  
          accepts float
          """
          self.width = width
          self.stale = True
  
      def set_height(self, height):
          """
          Set the height
  
          accepts float
          """
          self.height = height
          self.stale = True
  
      def get_visible_children(self):
          """
          Return a list of visible artists it contains.
          """
          return [c for c in self._children if c.get_visible()]
  
      def get_children(self):
          """
          Return a list of artists it contains.
          """
          return self._children
  
      def get_extent_offsets(self, renderer):
          raise Exception("")
  
      def get_extent(self, renderer):
          """
          Return with, height, xdescent, ydescent of box
          """
          w, h, xd, yd, offsets = self.get_extent_offsets(renderer)
          return w, h, xd, yd
  
      def get_window_extent(self, renderer):
          '''
          get the bounding box in display space.
          '''
          w, h, xd, yd, offsets = self.get_extent_offsets(renderer)
          px, py = self.get_offset(w, h, xd, yd, renderer)
          return mtransforms.Bbox.from_bounds(px - xd, py - yd, w, h)
  
      def draw(self, renderer):
          """
          Update the location of children if necessary and draw them
          to the given *renderer*.
          """
  
          width, height, xdescent, ydescent, offsets = self.get_extent_offsets(
                                                          renderer)
  
          px, py = self.get_offset(width, height, xdescent, ydescent, renderer)
  
          for c, (ox, oy) in zip(self.get_visible_children(), offsets):
              c.set_offset((px + ox, py + oy))
              c.draw(renderer)
  
          bbox_artist(self, renderer, fill=False, props=dict(pad=0.))
          self.stale = False
  
  
  class PackerBase(OffsetBox):
      def __init__(self, pad=None, sep=None, width=None, height=None,
                   align=None, mode=None,
                   children=None):
          """
          Parameters
          ----------
          pad : float, optional
              Boundary pad.
  
          sep : float, optional
              Spacing between items.
  
          width : float, optional
  
          height : float, optional
             Width and height of the container box, calculated if
             `None`.
  
          align : str, optional
              Alignment of boxes. Can be one of ``top``, ``bottom``,
              ``left``, ``right``, ``center`` and ``baseline``
  
          mode : str, optional
              Packing mode.
  
          Notes
          -----
          *pad* and *sep* need to given in points and will be scale with
          the renderer dpi, while *width* and *height* need to be in
          pixels.
          """
          super(PackerBase, self).__init__()
  
          self.height = height
          self.width = width
          self.sep = sep
          self.pad = pad
          self.mode = mode
          self.align = align
  
          self._children = children
  
  
  class VPacker(PackerBase):
      """
      The VPacker has its children packed vertically. It automatically
      adjust the relative positions of children in the drawing time.
      """
      def __init__(self, pad=None, sep=None, width=None, height=None,
                   align="baseline", mode="fixed",
                   children=None):
          """
          Parameters
          ----------
          pad : float, optional
              Boundary pad.
  
          sep : float, optional
              Spacing between items.
  
          width : float, optional
  
          height : float, optional
  
              width and height of the container box, calculated if
              `None`.
  
          align : str, optional
              Alignment of boxes.
  
          mode : str, optional
              Packing mode.
  
          Notes
          -----
          *pad* and *sep* need to given in points and will be scale with
          the renderer dpi, while *width* and *height* need to be in
          pixels.
          """
          super(VPacker, self).__init__(pad, sep, width, height,
                                        align, mode,
                                        children)
  
      def get_extent_offsets(self, renderer):
          """
          update offset of childrens and return the extents of the box
          """
  
          dpicor = renderer.points_to_pixels(1.)
          pad = self.pad * dpicor
          sep = self.sep * dpicor
  
          if self.width is not None:
              for c in self.get_visible_children():
                  if isinstance(c, PackerBase) and c.mode == "expand":
                      c.set_width(self.width)
  
          whd_list = [c.get_extent(renderer)
                      for c in self.get_visible_children()]
          whd_list = [(w, h, xd, (h - yd)) for w, h, xd, yd in whd_list]
  
          wd_list = [(w, xd) for w, h, xd, yd in whd_list]
          width, xdescent, xoffsets = _get_aligned_offsets(wd_list,
                                                           self.width,
                                                           self.align)
  
          pack_list = [(h, yd) for w, h, xd, yd in whd_list]
          height, yoffsets_ = _get_packed_offsets(pack_list, self.height,
                                                  sep, self.mode)
  
          yoffsets = yoffsets_ + [yd for w, h, xd, yd in whd_list]
          ydescent = height - yoffsets[0]
          yoffsets = height - yoffsets
  
          #w, h, xd, h_yd = whd_list[-1]
          yoffsets = yoffsets - ydescent
  
          return width + 2 * pad, height + 2 * pad, \
                 xdescent + pad, ydescent + pad, \
                 list(zip(xoffsets, yoffsets))
  
  
  class HPacker(PackerBase):
      """
      The HPacker has its children packed horizontally. It automatically
      adjusts the relative positions of children at draw time.
      """
      def __init__(self, pad=None, sep=None, width=None, height=None,
                   align="baseline", mode="fixed",
                   children=None):
          """
          Parameters
          ----------
          pad : float, optional
              Boundary pad.
  
          sep : float, optional
              Spacing between items.
  
          width : float, optional
  
          height : float, optional
             Width and height of the container box, calculated if
             `None`.
  
          align : str
             Alignment of boxes.
  
          mode : str
             Packing mode.
  
          Notes
          -----
          *pad* and *sep* need to given in points and will be scale with
          the renderer dpi, while *width* and *height* need to be in
          pixels.
          """
          super(HPacker, self).__init__(pad, sep, width, height,
                                        align, mode, children)
  
      def get_extent_offsets(self, renderer):
          """
          update offset of children and return the extents of the box
          """
          dpicor = renderer.points_to_pixels(1.)
          pad = self.pad * dpicor
          sep = self.sep * dpicor
  
          whd_list = [c.get_extent(renderer)
                      for c in self.get_visible_children()]
  
          if not whd_list:
              return 2 * pad, 2 * pad, pad, pad, []
  
          if self.height is None:
              height_descent = max([h - yd for w, h, xd, yd in whd_list])
              ydescent = max([yd for w, h, xd, yd in whd_list])
              height = height_descent + ydescent
          else:
              height = self.height - 2 * pad  # width w/o pad
  
          hd_list = [(h, yd) for w, h, xd, yd in whd_list]
          height, ydescent, yoffsets = _get_aligned_offsets(hd_list,
                                                            self.height,
                                                            self.align)
  
          pack_list = [(w, xd) for w, h, xd, yd in whd_list]
  
          width, xoffsets_ = _get_packed_offsets(pack_list, self.width,
                                                 sep, self.mode)
  
          xoffsets = xoffsets_ + [xd for w, h, xd, yd in whd_list]
  
          xdescent = whd_list[0][2]
          xoffsets = xoffsets - xdescent
  
          return width + 2 * pad, height + 2 * pad, \
                 xdescent + pad, ydescent + pad, \
                 list(zip(xoffsets, yoffsets))
  
  
  class PaddedBox(OffsetBox):
      def __init__(self, child, pad=None, draw_frame=False, patch_attrs=None):
          """
          *pad* : boundary pad
  
          .. note::
            *pad* need to given in points and will be
            scale with the renderer dpi, while *width* and *height*
            need to be in pixels.
          """
  
          super(PaddedBox, self).__init__()
  
          self.pad = pad
          self._children = [child]
  
          self.patch = FancyBboxPatch(
              xy=(0.0, 0.0), width=1., height=1.,
              facecolor='w', edgecolor='k',
              mutation_scale=1,  # self.prop.get_size_in_points(),
              snap=True
              )
  
          self.patch.set_boxstyle("square", pad=0)
  
          if patch_attrs is not None:
              self.patch.update(patch_attrs)
  
          self._drawFrame = draw_frame
  
      def get_extent_offsets(self, renderer):
          """
          update offset of childrens and return the extents of the box
          """
  
          dpicor = renderer.points_to_pixels(1.)
          pad = self.pad * dpicor
  
          w, h, xd, yd = self._children[0].get_extent(renderer)
  
          return w + 2 * pad, h + 2 * pad, \
                 xd + pad, yd + pad, \
                 [(0, 0)]
  
      def draw(self, renderer):
          """
          Update the location of children if necessary and draw them
          to the given *renderer*.
          """
  
          width, height, xdescent, ydescent, offsets = self.get_extent_offsets(
                                                          renderer)
  
          px, py = self.get_offset(width, height, xdescent, ydescent, renderer)
  
          for c, (ox, oy) in zip(self.get_visible_children(), offsets):
              c.set_offset((px + ox, py + oy))
  
          self.draw_frame(renderer)
  
          for c in self.get_visible_children():
              c.draw(renderer)
  
          #bbox_artist(self, renderer, fill=False, props=dict(pad=0.))
          self.stale = False
  
      def update_frame(self, bbox, fontsize=None):
          self.patch.set_bounds(bbox.x0, bbox.y0,
                                bbox.width, bbox.height)
  
          if fontsize:
              self.patch.set_mutation_scale(fontsize)
          self.stale = True
  
      def draw_frame(self, renderer):
          # update the location and size of the legend
          bbox = self.get_window_extent(renderer)
          self.update_frame(bbox)
  
          if self._drawFrame:
              self.patch.draw(renderer)
  
  
  class DrawingArea(OffsetBox):
      """
      The DrawingArea can contain any Artist as a child. The DrawingArea
      has a fixed width and height. The position of children relative to
      the parent is fixed. The children can be clipped at the
      boundaries of the parent.
      """
  
      def __init__(self, width, height, xdescent=0.,
                   ydescent=0., clip=False):
          """
          *width*, *height* : width and height of the container box.
          *xdescent*, *ydescent* : descent of the box in x- and y-direction.
          *clip* : Whether to clip the children
          """
  
          super(DrawingArea, self).__init__()
  
          self.width = width
          self.height = height
          self.xdescent = xdescent
          self.ydescent = ydescent
          self._clip_children = clip
  
          self.offset_transform = mtransforms.Affine2D()
          self.offset_transform.clear()
          self.offset_transform.translate(0, 0)
  
          self.dpi_transform = mtransforms.Affine2D()
  
      @property
      def clip_children(self):
          """
          If the children of this DrawingArea should be clipped
          by DrawingArea bounding box.
          """
          return self._clip_children
  
      @clip_children.setter
      def clip_children(self, val):
          self._clip_children = bool(val)
          self.stale = True
  
      def get_transform(self):
          """
          Return the :class:`~matplotlib.transforms.Transform` applied
          to the children
          """
          return self.dpi_transform + self.offset_transform
  
      def set_transform(self, t):
          """
          set_transform is ignored.
          """
          pass
  
      def set_offset(self, xy):
          """
          set offset of the container.
  
          Accept : tuple of x,y cooridnate in disokay units.
          """
          self._offset = xy
  
          self.offset_transform.clear()
          self.offset_transform.translate(xy[0], xy[1])
          self.stale = True
  
      def get_offset(self):
          """
          return offset of the container.
          """
          return self._offset
  
      def get_window_extent(self, renderer):
          '''
          get the bounding box in display space.
          '''
          w, h, xd, yd = self.get_extent(renderer)
          ox, oy = self.get_offset()  # w, h, xd, yd)
  
          return mtransforms.Bbox.from_bounds(ox - xd, oy - yd, w, h)
  
      def get_extent(self, renderer):
          """
          Return with, height, xdescent, ydescent of box
          """
  
          dpi_cor = renderer.points_to_pixels(1.)
          return self.width * dpi_cor, self.height * dpi_cor, \
                 self.xdescent * dpi_cor, self.ydescent * dpi_cor
  
      def add_artist(self, a):
          'Add any :class:`~matplotlib.artist.Artist` to the container box'
          self._children.append(a)
          if not a.is_transform_set():
              a.set_transform(self.get_transform())
          if self.axes is not None:
              a.axes = self.axes
          fig = self.figure
          if fig is not None:
              a.set_figure(fig)
  
      def draw(self, renderer):
          """
          Draw the children
          """
  
          dpi_cor = renderer.points_to_pixels(1.)
          self.dpi_transform.clear()
          self.dpi_transform.scale(dpi_cor, dpi_cor)
  
          # At this point the DrawingArea has a transform
          # to the display space so the path created is
          # good for clipping children
          tpath = mtransforms.TransformedPath(
              mpath.Path([[0, 0], [0, self.height],
                          [self.width, self.height],
                          [self.width, 0]]),
              self.get_transform())
          for c in self._children:
              if self._clip_children and not (c.clipbox or c._clippath):
                  c.set_clip_path(tpath)
              c.draw(renderer)
  
          bbox_artist(self, renderer, fill=False, props=dict(pad=0.))
          self.stale = False
  
  
  class TextArea(OffsetBox):
      """
      The TextArea is contains a single Text instance. The text is
      placed at (0,0) with baseline+left alignment. The width and height
      of the TextArea instance is the width and height of the its child
      text.
      """
      def __init__(self, s,
                   textprops=None,
                   multilinebaseline=None,
                   minimumdescent=True,
                   ):
          """
          Parameters
          ----------
          s : str
              a string to be displayed.
  
          textprops : `~matplotlib.font_manager.FontProperties`, optional
  
          multilinebaseline : bool, optional
              If `True`, baseline for multiline text is adjusted so that
              it is (approximatedly) center-aligned with singleline
              text.
  
          minimumdescent : bool, optional
              If `True`, the box has a minimum descent of "p".
          """
          if textprops is None:
              textprops = {}
  
          if "va" not in textprops:
              textprops["va"] = "baseline"
  
          self._text = mtext.Text(0, 0, s, **textprops)
  
          OffsetBox.__init__(self)
  
          self._children = [self._text]
  
          self.offset_transform = mtransforms.Affine2D()
          self.offset_transform.clear()
          self.offset_transform.translate(0, 0)
          self._baseline_transform = mtransforms.Affine2D()
          self._text.set_transform(self.offset_transform +
                                   self._baseline_transform)
  
          self._multilinebaseline = multilinebaseline
          self._minimumdescent = minimumdescent
  
      def set_text(self, s):
          "Set the text of this area as a string."
          self._text.set_text(s)
          self.stale = True
  
      def get_text(self):
          "Returns the string representation of this area's text"
          return self._text.get_text()
  
      def set_multilinebaseline(self, t):
          """
          Set multilinebaseline .
  
          If True, baseline for multiline text is
          adjusted so that it is (approximatedly) center-aligned with
          singleline text.
          """
          self._multilinebaseline = t
          self.stale = True
  
      def get_multilinebaseline(self):
          """
          get multilinebaseline .
          """
          return self._multilinebaseline
  
      def set_minimumdescent(self, t):
          """
          Set minimumdescent .
  
          If True, extent of the single line text is adjusted so that
          it has minimum descent of "p"
          """
          self._minimumdescent = t
          self.stale = True
  
      def get_minimumdescent(self):
          """
          get minimumdescent.
          """
          return self._minimumdescent
  
      def set_transform(self, t):
          """
          set_transform is ignored.
          """
          pass
  
      def set_offset(self, xy):
          """
          set offset of the container.
  
          Accept : tuple of x,y coordinates in display units.
          """
          self._offset = xy
  
          self.offset_transform.clear()
          self.offset_transform.translate(xy[0], xy[1])
          self.stale = True
  
      def get_offset(self):
          """
          return offset of the container.
          """
          return self._offset
  
      def get_window_extent(self, renderer):
          '''
          get the bounding box in display space.
          '''
          w, h, xd, yd = self.get_extent(renderer)
          ox, oy = self.get_offset()  # w, h, xd, yd)
          return mtransforms.Bbox.from_bounds(ox - xd, oy - yd, w, h)
  
      def get_extent(self, renderer):
          clean_line, ismath = self._text.is_math_text(self._text._text)
          _, h_, d_ = renderer.get_text_width_height_descent(
              "lp", self._text._fontproperties, ismath=False)
  
          bbox, info, d = self._text._get_layout(renderer)
          w, h = bbox.width, bbox.height
  
          line = info[-1][0]  # last line
  
          self._baseline_transform.clear()
  
          if len(info) > 1 and self._multilinebaseline:
              d_new = 0.5 * h - 0.5 * (h_ - d_)
              self._baseline_transform.translate(0, d - d_new)
              d = d_new
  
          else:  # single line
  
              h_d = max(h_ - d_, h - d)
  
              if self.get_minimumdescent():
                  ## to have a minimum descent, #i.e., "l" and "p" have same
                  ## descents.
                  d = max(d, d_)
              #else:
              #    d = d
  
              h = h_d + d
  
          return w, h, 0., d
  
      def draw(self, renderer):
          """
          Draw the children
          """
  
          self._text.draw(renderer)
  
          bbox_artist(self, renderer, fill=False, props=dict(pad=0.))
          self.stale = False
  
  
  class AuxTransformBox(OffsetBox):
      """
      Offset Box with the aux_transform . Its children will be
      transformed with the aux_transform first then will be
      offseted. The absolute coordinate of the aux_transform is meaning
      as it will be automatically adjust so that the left-lower corner
      of the bounding box of children will be set to (0,0) before the
      offset transform.
  
      It is similar to drawing area, except that the extent of the box
      is not predetermined but calculated from the window extent of its
      children. Furthermore, the extent of the children will be
      calculated in the transformed coordinate.
      """
      def __init__(self, aux_transform):
          self.aux_transform = aux_transform
          OffsetBox.__init__(self)
  
          self.offset_transform = mtransforms.Affine2D()
          self.offset_transform.clear()
          self.offset_transform.translate(0, 0)
  
          # ref_offset_transform is used to make the offset_transform is
          # always reference to the lower-left corner of the bbox of its
          # children.
          self.ref_offset_transform = mtransforms.Affine2D()
          self.ref_offset_transform.clear()
  
      def add_artist(self, a):
          'Add any :class:`~matplotlib.artist.Artist` to the container box'
          self._children.append(a)
          a.set_transform(self.get_transform())
          self.stale = True
  
      def get_transform(self):
          """
          Return the :class:`~matplotlib.transforms.Transform` applied
          to the children
          """
          return self.aux_transform + \
                 self.ref_offset_transform + \
                 self.offset_transform
  
      def set_transform(self, t):
          """
          set_transform is ignored.
          """
          pass
  
      def set_offset(self, xy):
          """
          set offset of the container.
  
          Accept : tuple of x,y coordinate in disokay units.
          """
          self._offset = xy
  
          self.offset_transform.clear()
          self.offset_transform.translate(xy[0], xy[1])
          self.stale = True
  
      def get_offset(self):
          """
          return offset of the container.
          """
          return self._offset
  
      def get_window_extent(self, renderer):
          '''
          get the bounding box in display space.
          '''
          w, h, xd, yd = self.get_extent(renderer)
          ox, oy = self.get_offset()  # w, h, xd, yd)
          return mtransforms.Bbox.from_bounds(ox - xd, oy - yd, w, h)
  
      def get_extent(self, renderer):
  
          # clear the offset transforms
          _off = self.offset_transform.to_values()  # to be restored later
          self.ref_offset_transform.clear()
          self.offset_transform.clear()
  
          # calculate the extent
          bboxes = [c.get_window_extent(renderer) for c in self._children]
          ub = mtransforms.Bbox.union(bboxes)
  
          # adjust ref_offset_tansform
          self.ref_offset_transform.translate(-ub.x0, -ub.y0)
  
          # restor offset transform
          mtx = self.offset_transform.matrix_from_values(*_off)
          self.offset_transform.set_matrix(mtx)
  
          return ub.width, ub.height, 0., 0.
  
      def draw(self, renderer):
          """
          Draw the children
          """
  
          for c in self._children:
              c.draw(renderer)
  
          bbox_artist(self, renderer, fill=False, props=dict(pad=0.))
          self.stale = False
  
  
  class AnchoredOffsetbox(OffsetBox):
      """
      An offset box placed according to the legend location
      loc. AnchoredOffsetbox has a single child. When multiple children
      is needed, use other OffsetBox class to enclose them.  By default,
      the offset box is anchored against its parent axes. You may
      explicitly specify the bbox_to_anchor.
      """
      zorder = 5  # zorder of the legend
  
      def __init__(self, loc,
                   pad=0.4, borderpad=0.5,
                   child=None, prop=None, frameon=True,
                   bbox_to_anchor=None,
                   bbox_transform=None,
                   **kwargs):
          """
          loc is a string or an integer specifying the legend location.
          The valid  location codes are::
  
          'upper right'  : 1,
          'upper left'   : 2,
          'lower left'   : 3,
          'lower right'  : 4,
          'right'        : 5,
          'center left'  : 6,
          'center right' : 7,
          'lower center' : 8,
          'upper center' : 9,
          'center'       : 10,
  
          pad : pad around the child for drawing a frame. given in
            fraction of fontsize.
  
          borderpad : pad between offsetbox frame and the bbox_to_anchor,
  
          child : OffsetBox instance that will be anchored.
  
          prop : font property. This is only used as a reference for paddings.
  
          frameon : draw a frame box if True.
  
          bbox_to_anchor : bbox to anchor. Use self.axes.bbox if None.
  
          bbox_transform : with which the bbox_to_anchor will be transformed.
  
          """
          super(AnchoredOffsetbox, self).__init__(**kwargs)
  
          self.set_bbox_to_anchor(bbox_to_anchor, bbox_transform)
          self.set_child(child)
  
          self.loc = loc
          self.borderpad = borderpad
          self.pad = pad
  
          if prop is None:
              self.prop = FontProperties(size=rcParams["legend.fontsize"])
          elif isinstance(prop, dict):
              self.prop = FontProperties(**prop)
              if "size" not in prop:
                  self.prop.set_size(rcParams["legend.fontsize"])
          else:
              self.prop = prop
  
          self.patch = FancyBboxPatch(
              xy=(0.0, 0.0), width=1., height=1.,
              facecolor='w', edgecolor='k',
              mutation_scale=self.prop.get_size_in_points(),
              snap=True
              )
          self.patch.set_boxstyle("square", pad=0)
          self._drawFrame = frameon
  
      def set_child(self, child):
          "set the child to be anchored"
          self._child = child
          if child is not None:
              child.axes = self.axes
          self.stale = True
  
      def get_child(self):
          "return the child"
          return self._child
  
      def get_children(self):
          "return the list of children"
          return [self._child]
  
      def get_extent(self, renderer):
          """
          return the extent of the artist. The extent of the child
          added with the pad is returned
          """
          w, h, xd, yd = self.get_child().get_extent(renderer)
          fontsize = renderer.points_to_pixels(self.prop.get_size_in_points())
          pad = self.pad * fontsize
  
          return w + 2 * pad, h + 2 * pad, xd + pad, yd + pad
  
      def get_bbox_to_anchor(self):
          """
          return the bbox that the legend will be anchored
          """
          if self._bbox_to_anchor is None:
              return self.axes.bbox
          else:
              transform = self._bbox_to_anchor_transform
              if transform is None:
                  return self._bbox_to_anchor
              else:
                  return TransformedBbox(self._bbox_to_anchor,
                                         transform)
  
      def set_bbox_to_anchor(self, bbox, transform=None):
          """
          set the bbox that the child will be anchored.
  
          *bbox* can be a Bbox instance, a list of [left, bottom, width,
          height], or a list of [left, bottom] where the width and
          height will be assumed to be zero. The bbox will be
          transformed to display coordinate by the given transform.
          """
          if bbox is None or isinstance(bbox, BboxBase):
              self._bbox_to_anchor = bbox
          else:
              try:
                  l = len(bbox)
              except TypeError:
                  raise ValueError("Invalid argument for bbox : %s" % str(bbox))
  
              if l == 2:
                  bbox = [bbox[0], bbox[1], 0, 0]
  
              self._bbox_to_anchor = Bbox.from_bounds(*bbox)
  
          self._bbox_to_anchor_transform = transform
          self.stale = True
  
      def get_window_extent(self, renderer):
          '''
          get the bounding box in display space.
          '''
          self._update_offset_func(renderer)
          w, h, xd, yd = self.get_extent(renderer)
          ox, oy = self.get_offset(w, h, xd, yd, renderer)
          return Bbox.from_bounds(ox - xd, oy - yd, w, h)
  
      def _update_offset_func(self, renderer, fontsize=None):
          """
          Update the offset func which depends on the dpi of the
          renderer (because of the padding).
          """
          if fontsize is None:
              fontsize = renderer.points_to_pixels(
                              self.prop.get_size_in_points())
  
          def _offset(w, h, xd, yd, renderer, fontsize=fontsize, self=self):
              bbox = Bbox.from_bounds(0, 0, w, h)
              borderpad = self.borderpad * fontsize
              bbox_to_anchor = self.get_bbox_to_anchor()
  
              x0, y0 = self._get_anchored_bbox(self.loc,
                                               bbox,
                                               bbox_to_anchor,
                                               borderpad)
              return x0 + xd, y0 + yd
  
          self.set_offset(_offset)
  
      def update_frame(self, bbox, fontsize=None):
          self.patch.set_bounds(bbox.x0, bbox.y0,
                                bbox.width, bbox.height)
  
          if fontsize:
              self.patch.set_mutation_scale(fontsize)
  
      def draw(self, renderer):
          "draw the artist"
  
          if not self.get_visible():
              return
  
          fontsize = renderer.points_to_pixels(self.prop.get_size_in_points())
          self._update_offset_func(renderer, fontsize)
  
          if self._drawFrame:
              # update the location and size of the legend
              bbox = self.get_window_extent(renderer)
              self.update_frame(bbox, fontsize)
              self.patch.draw(renderer)
  
          width, height, xdescent, ydescent = self.get_extent(renderer)
  
          px, py = self.get_offset(width, height, xdescent, ydescent, renderer)
  
          self.get_child().set_offset((px, py))
          self.get_child().draw(renderer)
          self.stale = False
  
      def _get_anchored_bbox(self, loc, bbox, parentbbox, borderpad):
          """
          return the position of the bbox anchored at the parentbbox
          with the loc code, with the borderpad.
          """
          assert loc in range(1, 11)  # called only internally
  
          BEST, UR, UL, LL, LR, R, CL, CR, LC, UC, C = list(xrange(11))
  
          anchor_coefs = {UR: "NE",
                          UL: "NW",
                          LL: "SW",
                          LR: "SE",
                          R: "E",
                          CL: "W",
                          CR: "E",
                          LC: "S",
                          UC: "N",
                          C: "C"}
  
          c = anchor_coefs[loc]
  
          container = parentbbox.padded(-borderpad)
          anchored_box = bbox.anchored(c, container=container)
          return anchored_box.x0, anchored_box.y0
  
  
  class AnchoredText(AnchoredOffsetbox):
      """
      AnchoredOffsetbox with Text.
      """
  
      def __init__(self, s, loc, pad=0.4, borderpad=0.5, prop=None, **kwargs):
          """
          Parameters
          ----------
          s : string
              Text.
  
          loc : str
              Location code.
  
          pad : float, optional
              Pad between the text and the frame as fraction of the font
              size.
  
          borderpad : float, optional
              Pad between the frame and the axes (or *bbox_to_anchor*).
  
          prop : `matplotlib.font_manager.FontProperties`
              Font properties.
  
          Notes
          -----
          Other keyword parameters of `AnchoredOffsetbox` are also
          allowed.
          """
  
          if prop is None:
              prop = {}
          propkeys = list(six.iterkeys(prop))
          badkwargs = ('ha', 'horizontalalignment', 'va', 'verticalalignment')
          if set(badkwargs) & set(propkeys):
              warnings.warn("Mixing horizontalalignment or verticalalignment "
                      "with AnchoredText is not supported.")
  
          self.txt = TextArea(s, textprops=prop,
                              minimumdescent=False)
          fp = self.txt._text.get_fontproperties()
  
          super(AnchoredText, self).__init__(loc, pad=pad, borderpad=borderpad,
                                             child=self.txt,
                                             prop=fp,
                                             **kwargs)
  
  
  class OffsetImage(OffsetBox):
      def __init__(self, arr,
                   zoom=1,
                   cmap=None,
                   norm=None,
                   interpolation=None,
                   origin=None,
                   filternorm=1,
                   filterrad=4.0,
                   resample=False,
                   dpi_cor=True,
                   **kwargs
                   ):
  
          OffsetBox.__init__(self)
          self._dpi_cor = dpi_cor
  
          self.image = BboxImage(bbox=self.get_window_extent,
                                 cmap=cmap,
                                 norm=norm,
                                 interpolation=interpolation,
                                 origin=origin,
                                 filternorm=filternorm,
                                 filterrad=filterrad,
                                 resample=resample,
                                 **kwargs
                                 )
  
          self._children = [self.image]
  
          self.set_zoom(zoom)
          self.set_data(arr)
  
      def set_data(self, arr):
          self._data = np.asarray(arr)
          self.image.set_data(self._data)
          self.stale = True
  
      def get_data(self):
          return self._data
  
      def set_zoom(self, zoom):
          self._zoom = zoom
          self.stale = True
  
      def get_zoom(self):
          return self._zoom
  
  #     def set_axes(self, axes):
  #         self.image.set_axes(axes)
  #         martist.Artist.set_axes(self, axes)
  
  #     def set_offset(self, xy):
  #         """
  #         set offset of the container.
  
  #         Accept : tuple of x,y coordinate in disokay units.
  #         """
  #         self._offset = xy
  
  #         self.offset_transform.clear()
  #         self.offset_transform.translate(xy[0], xy[1])
  
      def get_offset(self):
          """
          return offset of the container.
          """
          return self._offset
  
      def get_children(self):
          return [self.image]
  
      def get_window_extent(self, renderer):
          '''
          get the bounding box in display space.
          '''
          w, h, xd, yd = self.get_extent(renderer)
          ox, oy = self.get_offset()
          return mtransforms.Bbox.from_bounds(ox - xd, oy - yd, w, h)
  
      def get_extent(self, renderer):
          if self._dpi_cor:  # True, do correction
              dpi_cor = renderer.points_to_pixels(1.)
          else:
              dpi_cor = 1.
  
          zoom = self.get_zoom()
          data = self.get_data()
          ny, nx = data.shape[:2]
          w, h = dpi_cor * nx * zoom, dpi_cor * ny * zoom
  
          return w, h, 0, 0
  
      def draw(self, renderer):
          """
          Draw the children
          """
          self.image.draw(renderer)
          # bbox_artist(self, renderer, fill=False, props=dict(pad=0.))
          self.stale = False
  
  
  class AnnotationBbox(martist.Artist, _AnnotationBase):
      """
      Annotation-like class, but with offsetbox instead of Text.
      """
      zorder = 3
  
      def __str__(self):
          return "AnnotationBbox(%g,%g)" % (self.xy[0], self.xy[1])
  
      @docstring.dedent_interpd
      def __init__(self, offsetbox, xy,
                   xybox=None,
                   xycoords='data',
                   boxcoords=None,
                   frameon=True, pad=0.4,  # BboxPatch
                   annotation_clip=None,
                   box_alignment=(0.5, 0.5),
                   bboxprops=None,
                   arrowprops=None,
                   fontsize=None,
                   **kwargs):
          """
          *offsetbox* : OffsetBox instance
  
          *xycoords* : same as Annotation but can be a tuple of two
             strings which are interpreted as x and y coordinates.
  
          *boxcoords* : similar to textcoords as Annotation but can be a
             tuple of two strings which are interpreted as x and y
             coordinates.
  
          *box_alignment* : a tuple of two floats for a vertical and
             horizontal alignment of the offset box w.r.t. the *boxcoords*.
             The lower-left corner is (0.0) and upper-right corner is (1.1).
  
          other parameters are identical to that of Annotation.
          """
  
          martist.Artist.__init__(self, **kwargs)
          _AnnotationBase.__init__(self,
                                   xy,
                                   xycoords=xycoords,
                                   annotation_clip=annotation_clip)
  
          self.offsetbox = offsetbox
  
          self.arrowprops = arrowprops
  
          self.set_fontsize(fontsize)
  
          if xybox is None:
              self.xybox = xy
          else:
              self.xybox = xybox
  
          if boxcoords is None:
              self.boxcoords = xycoords
          else:
              self.boxcoords = boxcoords
  
          if arrowprops is not None:
              self._arrow_relpos = self.arrowprops.pop("relpos", (0.5, 0.5))
              self.arrow_patch = FancyArrowPatch((0, 0), (1, 1),
                                                 **self.arrowprops)
          else:
              self._arrow_relpos = None
              self.arrow_patch = None
  
          #self._fw, self._fh = 0., 0. # for alignment
          self._box_alignment = box_alignment
  
          # frame
          self.patch = FancyBboxPatch(
              xy=(0.0, 0.0), width=1., height=1.,
              facecolor='w', edgecolor='k',
              mutation_scale=self.prop.get_size_in_points(),
              snap=True
              )
          self.patch.set_boxstyle("square", pad=pad)
          if bboxprops:
              self.patch.set(**bboxprops)
          self._drawFrame = frameon
  
      @property
      def xyann(self):
          return self.xybox
  
      @xyann.setter
      def xyann(self, xyann):
          self.xybox = xyann
          self.stale = True
  
      @property
      def anncoords(self):
          return self.boxcoords
  
      @anncoords.setter
      def anncoords(self, coords):
          self.boxcoords = coords
          self.stale = True
  
      def contains(self, event):
          t, tinfo = self.offsetbox.contains(event)
          #if self.arrow_patch is not None:
          #    a,ainfo=self.arrow_patch.contains(event)
          #    t = t or a
  
          # self.arrow_patch is currently not checked as this can be a line - JJ
  
          return t, tinfo
  
      def get_children(self):
          children = [self.offsetbox, self.patch]
          if self.arrow_patch:
              children.append(self.arrow_patch)
          return children
  
      def set_figure(self, fig):
  
          if self.arrow_patch is not None:
              self.arrow_patch.set_figure(fig)
          self.offsetbox.set_figure(fig)
          martist.Artist.set_figure(self, fig)
  
      def set_fontsize(self, s=None):
          """
          set fontsize in points
          """
          if s is None:
              s = rcParams["legend.fontsize"]
  
          self.prop = FontProperties(size=s)
          self.stale = True
  
      def get_fontsize(self, s=None):
          """
          return fontsize in points
          """
          return self.prop.get_size_in_points()
  
      def update_positions(self, renderer):
          """
          Update the pixel positions of the annotated point and the text.
          """
          xy_pixel = self._get_position_xy(renderer)
          self._update_position_xybox(renderer, xy_pixel)
  
          mutation_scale = renderer.points_to_pixels(self.get_fontsize())
          self.patch.set_mutation_scale(mutation_scale)
  
          if self.arrow_patch:
              self.arrow_patch.set_mutation_scale(mutation_scale)
  
      def _update_position_xybox(self, renderer, xy_pixel):
          """
          Update the pixel positions of the annotation text and the arrow
          patch.
          """
  
          x, y = self.xybox
          if isinstance(self.boxcoords, tuple):
              xcoord, ycoord = self.boxcoords
              x1, y1 = self._get_xy(renderer, x, y, xcoord)
              x2, y2 = self._get_xy(renderer, x, y, ycoord)
              ox0, oy0 = x1, y2
          else:
              ox0, oy0 = self._get_xy(renderer, x, y, self.boxcoords)
  
          w, h, xd, yd = self.offsetbox.get_extent(renderer)
  
          _fw, _fh = self._box_alignment
          self.offsetbox.set_offset((ox0 - _fw * w + xd, oy0 - _fh * h + yd))
  
          # update patch position
          bbox = self.offsetbox.get_window_extent(renderer)
          #self.offsetbox.set_offset((ox0-_fw*w, oy0-_fh*h))
          self.patch.set_bounds(bbox.x0, bbox.y0,
                                bbox.width, bbox.height)
  
          x, y = xy_pixel
  
          ox1, oy1 = x, y
  
          if self.arrowprops:
              x0, y0 = x, y
  
              d = self.arrowprops.copy()
  
              # Use FancyArrowPatch if self.arrowprops has "arrowstyle" key.
  
              # adjust the starting point of the arrow relative to
              # the textbox.
              # TODO : Rotation needs to be accounted.
              relpos = self._arrow_relpos
  
              ox0 = bbox.x0 + bbox.width * relpos[0]
              oy0 = bbox.y0 + bbox.height * relpos[1]
  
              # The arrow will be drawn from (ox0, oy0) to (ox1,
              # oy1). It will be first clipped by patchA and patchB.
              # Then it will be shrinked by shirnkA and shrinkB
              # (in points). If patch A is not set, self.bbox_patch
              # is used.
  
              self.arrow_patch.set_positions((ox0, oy0), (ox1, oy1))
              fs = self.prop.get_size_in_points()
              mutation_scale = d.pop("mutation_scale", fs)
              mutation_scale = renderer.points_to_pixels(mutation_scale)
              self.arrow_patch.set_mutation_scale(mutation_scale)
  
              patchA = d.pop("patchA", self.patch)
              self.arrow_patch.set_patchA(patchA)
  
      def draw(self, renderer):
          """
          Draw the :class:`Annotation` object to the given *renderer*.
          """
  
          if renderer is not None:
              self._renderer = renderer
          if not self.get_visible():
              return
  
          xy_pixel = self._get_position_xy(renderer)
  
          if not self._check_xy(renderer, xy_pixel):
              return
  
          self.update_positions(renderer)
  
          if self.arrow_patch is not None:
              if self.arrow_patch.figure is None and self.figure is not None:
                  self.arrow_patch.figure = self.figure
              self.arrow_patch.draw(renderer)
  
          if self._drawFrame:
              self.patch.draw(renderer)
  
          self.offsetbox.draw(renderer)
          self.stale = False
  
  
  class DraggableBase(object):
      """
      helper code for a draggable artist (legend, offsetbox)
      The derived class must override following two method.
  
        def saveoffset(self):
            pass
  
        def update_offset(self, dx, dy):
            pass
  
      *saveoffset* is called when the object is picked for dragging and it is
      meant to save reference position of the artist.
  
      *update_offset* is called during the dragging. dx and dy is the pixel
       offset from the point where the mouse drag started.
  
      Optionally you may override following two methods.
  
        def artist_picker(self, artist, evt):
            return self.ref_artist.contains(evt)
  
        def finalize_offset(self):
            pass
  
      *artist_picker* is a picker method that will be
       used. *finalize_offset* is called when the mouse is released. In
       current implementaion of DraggableLegend and DraggableAnnotation,
       *update_offset* places the artists simply in display
       coordinates. And *finalize_offset* recalculate their position in
       the normalized axes coordinate and set a relavant attribute.
  
      """
      def __init__(self, ref_artist, use_blit=False):
          self.ref_artist = ref_artist
          self.got_artist = False
  
          self.canvas = self.ref_artist.figure.canvas
          self._use_blit = use_blit and self.canvas.supports_blit
  
          c2 = self.canvas.mpl_connect('pick_event', self.on_pick)
          c3 = self.canvas.mpl_connect('button_release_event', self.on_release)
  
          ref_artist.set_picker(self.artist_picker)
          self.cids = [c2, c3]
  
      def on_motion(self, evt):
          if self.got_artist:
              dx = evt.x - self.mouse_x
              dy = evt.y - self.mouse_y
              self.update_offset(dx, dy)
              self.canvas.draw()
  
      def on_motion_blit(self, evt):
          if self.got_artist:
              dx = evt.x - self.mouse_x
              dy = evt.y - self.mouse_y
              self.update_offset(dx, dy)
              self.canvas.restore_region(self.background)
              self.ref_artist.draw(self.ref_artist.figure._cachedRenderer)
              self.canvas.blit(self.ref_artist.figure.bbox)
  
      def on_pick(self, evt):
          if evt.artist == self.ref_artist:
  
              self.mouse_x = evt.mouseevent.x
              self.mouse_y = evt.mouseevent.y
              self.got_artist = True
  
              if self._use_blit:
                  self.ref_artist.set_animated(True)
                  self.canvas.draw()
                  self.background = self.canvas.copy_from_bbox(
                                      self.ref_artist.figure.bbox)
                  self.ref_artist.draw(self.ref_artist.figure._cachedRenderer)
                  self.canvas.blit(self.ref_artist.figure.bbox)
                  self._c1 = self.canvas.mpl_connect('motion_notify_event',
                                                     self.on_motion_blit)
              else:
                  self._c1 = self.canvas.mpl_connect('motion_notify_event',
                                                     self.on_motion)
              self.save_offset()
  
      def on_release(self, event):
          if self.got_artist:
              self.finalize_offset()
              self.got_artist = False
              self.canvas.mpl_disconnect(self._c1)
  
              if self._use_blit:
                  self.ref_artist.set_animated(False)
  
      def disconnect(self):
          """disconnect the callbacks"""
          for cid in self.cids:
              self.canvas.mpl_disconnect(cid)
          try:
              c1 = self._c1
          except AttributeError:
              pass
          else:
              self.canvas.mpl_disconnect(c1)
  
      def artist_picker(self, artist, evt):
          return self.ref_artist.contains(evt)
  
      def save_offset(self):
          pass
  
      def update_offset(self, dx, dy):
          pass
  
      def finalize_offset(self):
          pass
  
  
  class DraggableOffsetBox(DraggableBase):
      def __init__(self, ref_artist, offsetbox, use_blit=False):
          DraggableBase.__init__(self, ref_artist, use_blit=use_blit)
          self.offsetbox = offsetbox
  
      def save_offset(self):
          offsetbox = self.offsetbox
          renderer = offsetbox.figure._cachedRenderer
          w, h, xd, yd = offsetbox.get_extent(renderer)
          offset = offsetbox.get_offset(w, h, xd, yd, renderer)
          self.offsetbox_x, self.offsetbox_y = offset
          self.offsetbox.set_offset(offset)
  
      def update_offset(self, dx, dy):
          loc_in_canvas = self.offsetbox_x + dx, self.offsetbox_y + dy
          self.offsetbox.set_offset(loc_in_canvas)
  
      def get_loc_in_canvas(self):
  
          offsetbox = self.offsetbox
          renderer = offsetbox.figure._cachedRenderer
          w, h, xd, yd = offsetbox.get_extent(renderer)
          ox, oy = offsetbox._offset
          loc_in_canvas = (ox - xd, oy - yd)
  
          return loc_in_canvas
  
  
  class DraggableAnnotation(DraggableBase):
      def __init__(self, annotation, use_blit=False):
          DraggableBase.__init__(self, annotation, use_blit=use_blit)
          self.annotation = annotation
  
      def save_offset(self):
          ann = self.annotation
          self.ox, self.oy = ann.get_transform().transform(ann.xyann)
  
      def update_offset(self, dx, dy):
          ann = self.annotation
          ann.xyann = ann.get_transform().inverted().transform(
              (self.ox + dx, self.oy + dy))
  
  
  if __name__ == "__main__":
      import matplotlib.pyplot as plt
      fig = plt.figure(1)
      fig.clf()
      ax = plt.subplot(121)
  
      #txt = ax.text(0.5, 0.5, "Test", size=30, ha="center", color="w")
      kwargs = dict()
  
      a = np.arange(256).reshape(16, 16) / 256.
      myimage = OffsetImage(a,
                            zoom=2,
                            norm=None,
                            origin=None,
                            **kwargs
                            )
      ax.add_artist(myimage)
  
      myimage.set_offset((100, 100))
  
      myimage2 = OffsetImage(a,
                             zoom=2,
                             norm=None,
                             origin=None,
                             **kwargs
                             )
      ann = AnnotationBbox(myimage2, (0.5, 0.5),
                           xybox=(30, 30),
                           xycoords='data',
                           boxcoords="offset points",
                           frameon=True, pad=0.4,  # BboxPatch
                           bboxprops=dict(boxstyle="round", fc="y"),
                           fontsize=None,
                           arrowprops=dict(arrowstyle="->"),
                           )
  
      ax.add_artist(ann)
  
      plt.draw()
      plt.show()
  