def _compute_bands(self, points, smartmode=False):
"""
Sorts self.data into a list of arrays of data points by color,
filling in self._index_bands. If *smartmode* is True, then it first
calls _calc_render_method() to see which rendering method is
optimal for the number of points and the distribution of
color indices; if the rendering method is 'bruteforce', then
this method short-circuits and returns without doing
anything.
"""
if len(points) == 0:
return
if self.color_mapper is None:
return
# map the V values in the (x,y,v) self.data array
color_data = points[:, 2]
color_indices = self.color_mapper.map_index(color_data)
if smartmode and self.render_method == 'bruteforce':
pass
else:
# shuffle_indices indicates how to sort the points in self.data
# so that their color_indices are in order. We don't really care
# about the sorting so much as the fact that once they are sorted,
# points of the same color are grouped together into "bands".
shuffle_indices = argsort(color_indices)
# This pulls values from the color_indices array into
# sorted_color_indices, using the results of the sort we just did.
sorted_color_indices = take(color_indices, shuffle_indices)
# Now we want to determine where the continuous bands are. We do
# this by right-shifting the sorted_color_indices array, subtracting
# it from the original, and looking for all the nonzero points.
shifted = right_shift(sorted_color_indices,
sorted_color_indices[0])
start_indices = concatenate([[0],
nonzero(sorted_color_indices -
shifted)[0]])
end_indices = left_shift(start_indices, len(sorted_color_indices))
# Store the shuffled indices in self._index_bands. We don't store the
# actual data points because we need to allow the renderer to index into
# the mapped XY screen positions.
self._index_bands = {}
for (start, end) in zip(start_indices, end_indices):
color_index = sorted_color_indices[start]
self._index_bands[color_index] = shuffle_indices[start:end]
self._color_indices = color_indices
self._cache_valid = True
return
def _compute_bands(self, points, smartmode=False):
"""
Sorts self.data into a list of arrays of data points by color,
filling in self._index_bands. If *smartmode* is True, then it first
calls _calc_render_method() to see which rendering method is
optimal for the number of points and the distribution of
color indices; if the rendering method is 'bruteforce', then
this method short-circuits and returns without doing
anything.
"""
if len(points) == 0:
return
if self.color_mapper is None:
return
# map the V values in the (x,y,v) self.data array
color_data = points[:,2]
color_indices = self.color_mapper.map_index(color_data)
if smartmode and self.render_method == 'bruteforce':
pass
else:
# shuffle_indices indicates how to sort the points in self.data
# so that their color_indices are in order. We don't really care
# about the sorting so much as the fact that once they are sorted,
# points of the same color are grouped together into "bands".
shuffle_indices = argsort(color_indices)
# This pulls values from the color_indices array into
# sorted_color_indices, using the results of the sort we just did.
sorted_color_indices = take(color_indices, shuffle_indices)
# Now we want to determine where the continuous bands are. We do
# this by right-shifting the sorted_color_indices array, subtracting
# it from the original, and looking for all the nonzero points.
shifted = right_shift(sorted_color_indices, sorted_color_indices[0])
start_indices = concatenate([[0], nonzero(sorted_color_indices - shifted)[0]])
end_indices = left_shift(start_indices, len(sorted_color_indices))
# Store the shuffled indices in self._index_bands. We don't store the
# actual data points because we need to allow the renderer to index into
# the mapped XY screen positions.
self._index_bands = {}
for (start, end) in zip(start_indices, end_indices):
color_index = sorted_color_indices[start]
self._index_bands[color_index] = shuffle_indices[start:end]
self._color_indices = color_indices
self._cache_valid = True
return