def quiver(point,
gradient,
length=None,
length_scale=1.,
width_scale=1.,
color=None,
opacity=None,
fig="gcf",
label=None):
"""Create arrow(s) from 'point' towards a direction given by 'gradient' to
make field/quiver plots. Arrow lengths by default are the magnitude of
'gradient but can be scaled with 'length_scale' or frozen with 'length'.
See arrow's docs for more detail.
:param point: The starting point of the arrow(s).
:type point: np.ndarray
:param gradient: The displacement / gradient vector.
:type gradient: np.ndarray
:param length: A frozen length for each arrow, defaults to None.
:type length: NoneType, optional
:param length_scale: A scaling factor for the length of each arrow, defaults to 1.0.
:type length_scale: int, optional
:param width_scale: How fat to make each arrow, is relative to its length, defaults to 1.0.
:type width_scale: int, optional
:param color: The color of each arrow, defaults to white.
:type color: str, 3-tuple, 4-tuple, np.ndarray of shape (n, 3)
:param opacity: The translucency of the plot, from `0` invisible to `1` solid, defaults to `1`.
:type opacity: float
:param fig: The figure to plot into, can be None, defaults to :meth:`vtkplotlib.gcf`.
:type fig: :class:`vtkplotlib.figure`, :class:`vtkplotlib.QtFigure`, optional
:param label: Give the plot a label to use in legends, defaults to None.
:type label: str, optional
:return: arrow or array of arrows
:rtype: vtkplotlib.plots.Arrow.Arrow, np.array of Arrows
.. seealso:: ``vpl.arrow`` to draw arrows from a start point to an end point.
"""
if length is None:
length = geom.distance(gradient)
if length_scale != 1:
length *= length_scale
return arrow(point, point + gradient, length, width_scale, color, opacity,
fig, label)
def quiver(point,
gradient,
length=None,
length_scale=1.,
width_scale=1.,
color=None,
opacity=None,
fig="gcf"):
"""Create an arrow from 'point' towards a direction given by 'gradient'.
This is intended to make field/quiver plots. Arrow lengths by default are
the magnitude of 'gradient but can be scaled with 'length_scale' or
frozen with 'length'. See arrow's docs for more detail.
:param point: The starting point of the arrow(s).
:type point: np.ndarray
:param gradient: The displacement / gradient vector.
:type gradient: np.ndarray
:param length: A frozen length for each arrow, defaults to None.
:type length: NoneType, optional
:param length_scale: A scaling factor for the length of each arrow, defaults to 1.0.
:type length_scale: int, optional
:param width_scale: How fat to make each arrow, is relative to its length, defaults to 1.0.
:type width_scale: int, optional
:param color: The color of each arrow, defaults to white.
:type color: str, 3-tuple, 4-tuple, np.ndarray of shape(n, 3)
:param opacity: The translucency of each arrow, 0 is invisible, 1 is solid, defaults to solid.
:type opacity: float
:param fig: The figure to plot into, can be None, defaults to vpl.gcf().
:type fig: vpl.figure, vpl.QtFigure
:return: arrow or array of arrows
:rtype: vtkplotlib.plots.Arrow.Arrow, np.array of Arrows
"""
if length is None:
length = geom.distance(gradient)
if length_scale != 1:
length *= length_scale
return arrow(point, point + gradient, length, width_scale, color, opacity,
fig)
def __init__(self,
start,
end,
length=None,
width_scale=1,
color=None,
opacity=None,
fig="gcf",
label=None):
super().__init__(fig)
diff = end - start
if length is None:
length = geom.distance(diff)
# vtk needs a full set of axes to build about.
# eX is just the direction the arrow is pointing in.
# eY and eZ must be perpendicular to each other and eX. However beyond
# that exact choice of eY and eZ does not matter. It only rotates the
# arrow about eX which you can't see because it's (approximately) round.
eX, eY, eZ = geom.orthogonal_bases(diff)
arrowSource = vtk.vtkArrowSource()
# This next bit puts the arrow where it's supposed to go
matrix = vtk.vtkMatrix4x4()
# Create the direction cosine matrix
matrix.Identity()
for i in range(3):
matrix.SetElement(i, 0, eX[i])
matrix.SetElement(i, 1, eY[i])
matrix.SetElement(i, 2, eZ[i])
# Apply the transforms
transform = vtk.vtkTransform()
transform.Translate(start)
transform.Concatenate(matrix)
transform.Scale(length, length * width_scale, length * width_scale)
self.source = arrowSource
self.connect()
self.actor.SetUserMatrix(transform.GetMatrix())
self.color_opacity(color, opacity)
self.label = label