def METHOD_NAME(self):
    """Collects the data points that are within the bounds of the plot and
    caches them.
    """
    if self._cache_valid:
        return
    index = self.index.get_data()
    value = self.value.get_data()
    if not self.index or not self.value:
        return
    if len(index) == 0 or len(value) == 0 or len(index) != len(value):
        self._cached_data_pts = []
        self._cache_valid = True
        return
    points = np.transpose(np.array((index, value)))
    self._cached_data_pts = points
    self._cache_valid = True