/usr/lib/python2.7/dist-packages/chaco/quiverplot.py is in python-chaco 4.5.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 | from __future__ import with_statement
from numpy import array, compress, matrix, newaxis, sqrt, zeros
# Enthought library imports
from enable.api import ColorTrait
from traits.api import Array, Enum, Float, Instance, Int
# Chaco relative imports
from abstract_data_source import AbstractDataSource
from scatterplot import ScatterPlot
class QuiverPlot(ScatterPlot):
# Determines how to interpret the data in the **vectors** data source.
# "vector": each tuple is a (dx, dy)
# "radial": each tuple is an (r, theta)
data_type = Enum("vector", "radial") # TODO: implement "radial"
# A datasource that returns an Nx2 array array indicating directions
# of the vectors. The interpretation of this array is dependent on
# the setting of the **data_type** attribute.
#
# Usually this will be a MultiArrayDataSource.
vectors = Instance(AbstractDataSource)
#------------------------------------------------------------------------
# Visual attributes of the vector
#------------------------------------------------------------------------
# The color of the lines
line_color = ColorTrait("black")
# The width of the lines
line_width = Float(1.0)
# The length, in pixels, of the arrowhead
arrow_size = Int(5)
#------------------------------------------------------------------------
# Private traits
#------------------------------------------------------------------------
_cached_vector_data = Array
_selected_vector_data = Array
def _gather_points_old(self):
# In addition to the standard scatterplot _gather_points, we need
# to also grab the vectors that fall inside the view range
super(QuiverPlot, self)._gather_points_old()
if not self.index or not self.value:
return
if len(self._cached_point_mask) == 0:
self._cached_vector_data = []
return
vectors = self.vectors.get_data()
self._cached_vector_data = compress(self._cached_point_mask, vectors, axis=0)
if self._cached_selected_pts is not None:
indices = self._cached_selection_point_mask
self._selected_vector_data = compress(indices, vectors, axis=0)
else:
self._selected_vector_data = None
return
def _render(self, gc, points, icon_mode=False):
with gc:
gc.clip_to_rect(self.x, self.y, self.width, self.height)
gc.set_stroke_color(self.line_color_)
gc.set_line_width(self.line_width)
# Draw the body of the arrow
starts = points
ends = points + self._cached_vector_data
gc.begin_path()
gc.line_set(starts, ends)
gc.stroke_path()
if self.arrow_size > 0:
vec = self._cached_vector_data
unit_vec = vec / sqrt(vec[:,0] ** 2 + vec[:,1] ** 2)[:, newaxis]
a = 0.707106781 # sqrt(2)/2
# Draw the left arrowhead (for an arrow pointing straight up)
arrow_ends = ends - array(unit_vec * matrix([[a, a], [-a, a]])) * self.arrow_size
gc.begin_path()
gc.line_set(ends, arrow_ends)
gc.stroke_path()
# Draw the left arrowhead (for an arrow pointing straight up)
arrow_ends = ends - array(unit_vec * matrix([[a, -a], [a, a]])) * self.arrow_size
gc.begin_path()
gc.line_set(ends, arrow_ends)
gc.stroke_path()
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