content: # -*- coding: utf-8 -*-
  # Copyright 2007-2011 The Hyperspy developers
  #
  # This file is part of  Hyperspy.
  #
  #  Hyperspy is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 3 of the License, or
  # (at your option) any later version.
  #
  #  Hyperspy is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with  Hyperspy.  If not, see <http://www.gnu.org/licenses/>.
  
  import matplotlib.pyplot as plt
  
  from hyperspy.drawing.marker import MarkerBase
  
  
  class HorizontalLineSegment(MarkerBase):
  
      """Horizontal line segment marker that can be added to the signal figure
  
      Parameters
      ---------
      x1: array or float
          The position of the start of the line segment in x.
          If float, the marker is fixed.
          If array, the marker will be updated when navigating. The array should
          have the same dimensions in the nagivation axes.
      x2: array or float
          The position of the end of the line segment in x.
          see x1 arguments
      y: array or float
          The position of line segment in y.
          see x1 arguments
      kwargs:
          Kewywords argument of axvline valid properties (i.e. recognized by
          mpl.plot).
  
      Example
      -------
      >>> import numpy as np
      >>> im = signals.Image(np.zeros((100, 100)))
      >>> m = utils.plot.markers.horizontal_line_segment(
      >>>     x1=20, x2=70, y=70, linewidth=4, color='red', linestyle='dotted')
      >>> im.add_marker(m)
  
      """
  
      def __init__(self, x1, x2, y, **kwargs):
          MarkerBase.__init__(self)
          lp = {}
          lp['color'] = 'black'
          lp['linewidth'] = 1
          self.marker_properties = lp
          self.set_data(x1=x1, x2=x2, y1=y)
          self.set_marker_properties(**kwargs)
  
      def update(self):
          if self.auto_update is False:
              return
          self._update_segment()
  
      def plot(self):
          if self.ax is None:
              raise AttributeError(
                  "To use this method the marker needs to be first add to a " +
                  "figure using `s._plot.signal_plot.add_marker(m)` or " +
                  "`s._plot.navigator_plot.add_marker(m)`")
          self.marker = self.ax.vlines(0, 0, 1, **self.marker_properties)
          self._update_segment()
          self.marker.set_animated(True)
          try:
              self.ax.hspy_fig._draw_animated()
          except:
              pass
  
      def _update_segment(self):
          segments = self.marker.get_segments()
          segments[0][0, 1] = self.get_data_position('y1')
          segments[0][1, 1] = segments[0][0, 1]
          if self.get_data_position('x1') is None:
              segments[0][0, 0] = plt.getp(self.marker.axes, 'xlim')[0]
          else:
              segments[0][0, 0] = self.get_data_position('x1')
          if self.get_data_position('x2') is None:
              segments[0][1, 0] = plt.getp(self.marker.axes, 'xlim')[1]
          else:
              segments[0][1, 0] = self.get_data_position('x2')
          self.marker.set_segments(segments)
  