code: def mouseMoved(self, viewPos):
          
          try:
              check_class(viewPos, QtCore.QPointF)
              self.crossLineVerShadow.setVisible(False)
              self.crossLineVertical.setVisible(False)
              self.probeLabel.setText("")
              self.probeDataItem.clear()
  
              if (self._hasValidData() and self.config.probeCti.configValue and
                  self.viewBox.sceneBoundingRect().contains(viewPos)):
  
                  scenePos = self.viewBox.mapSceneToView(viewPos)
                  index = int(scenePos.x())
                  data = self.slicedArray.data
  
                  if not 0 <= index < len(data):
                      txt = "<span style='color: grey'>no data at cursor</span>"
                      self.probeLabel.setText(txt)
                  else:
                      valueStr = to_string(data[index], masked=self.slicedArray.maskAt(index),
                                           maskFormat='&lt;masked&gt;')
                      self.probeLabel.setText("pos = {!r}, value = {}".format(index, valueStr))
                      if np.isfinite(data[index]):
                          self.crossLineVerShadow.setVisible(True)
                          self.crossLineVerShadow.setPos(index)
                          self.crossLineVertical.setVisible(True)
                          self.crossLineVertical.setPos(index)
                          if data[index] > 0 or self.config.yLogCti.configValue == False:
                              self.probeDataItem.setData((index,), (data[index],))
  
          except Exception as ex:
              # In contrast to _drawContents, this function is a slot and thus must not throw
              # exceptions. The exception is logged. Perhaps we should clear the cross plots, but
              # this could, in turn, raise exceptions.
              if DEBUGGING:
                  raise
              else:
                  logger.exception(ex)
docs: Updates the probe text with the values under the cursor.
              Draws a vertical line and a symbol at the position of the probe.