def numpy_to_vtk_cells(data, is_coords=True):
"""Convert numpy array to a vtk cell array.
Parameters
----------
data : ndarray
points coordinate or connectivity array (e.g triangles).
is_coords : ndarray
Select the type of array. default: True.
Returns
-------
vtk_cell : vtkCellArray
connectivity + offset information
"""
data = np.array(data, dtype=object)
nb_cells = len(data)
# Get lines_array in vtk input format
connectivity = data.flatten() if not is_coords else []
offset = [0, ]
current_position = 0
cell_array = CellArray()
if VTK_9_PLUS:
for i in range(nb_cells):
current_len = len(data[i])
offset.append(offset[-1] + current_len)
if is_coords:
end_position = current_position + current_len
connectivity += list(range(current_position, end_position))
current_position = end_position
connectivity = np.array(connectivity, np.intp)
offset = np.array(offset, dtype=connectivity.dtype)
vtk_array_type = numpy_support.get_vtk_array_type(connectivity.dtype)
cell_array.SetData(
numpy_support.numpy_to_vtk(offset, deep=True,
array_type=vtk_array_type),
numpy_support.numpy_to_vtk(connectivity, deep=True,
array_type=vtk_array_type))
else:
for i in range(nb_cells):
current_len = len(data[i])
end_position = current_position + current_len
connectivity += [current_len]
connectivity += list(range(current_position, end_position))
current_position = end_position
connectivity = np.array(connectivity)
cell_array.GetData().DeepCopy(numpy_support.numpy_to_vtk(connectivity))
cell_array.SetNumberOfCells(nb_cells)
return cell_array
def _points_to_vtk_cells(points, points_per_line=2):
"""
Returns the VTK cell array for the peaks given the set of points
coordinates.
Parameters
----------
points : (N, 3) array or ndarray
points coordinates array.
points_per_line : int (1 or 2), optional
number of points per peak direction.
Returns
-------
cell_array : vtkCellArray
connectivity + offset information.
"""
num_pnts = len(points)
num_cells = num_pnts // points_per_line
cell_array = CellArray()
"""
Connectivity is an array that contains the indices of the points that
need to be connected in the visualization. The indices start from 0.
"""
connectivity = np.asarray(list(range(0, num_pnts)), dtype=int)
"""
Offset is an array that contains the indices of the first point of
each line. The indices start from 0 and given the known geometry of
this actor the creation of this array requires a 2 points padding
between indices.
"""
offset = np.asarray(list(range(0, num_pnts + 1, points_per_line)),
dtype=int)
vtk_array_type = numpy_support.get_vtk_array_type(connectivity.dtype)
cell_array.SetData(
numpy_support.numpy_to_vtk(offset,
deep=True,
array_type=vtk_array_type),
numpy_support.numpy_to_vtk(connectivity,
deep=True,
array_type=vtk_array_type))
cell_array.SetNumberOfCells(num_cells)
return cell_array
def _points_to_vtk_cells(points, points_per_line=2):
"""
Returns the VTK cell array for the peaks given the set of points
coordinates.
Parameters
----------
points : (N, 3) array or ndarray
points coordinates array.
points_per_line : int (1 or 2), optional
number of points per peak direction.
Returns
-------
cell_array : vtkCellArray
connectivity + offset information.
"""
num_pnts = len(points)
num_cells = num_pnts // points_per_line
cell_array = CellArray()
if VTK_9_PLUS:
"""
Connectivity is an array that contains the indices of the points that
need to be connected in the visualization. The indices start from 0.
"""
connectivity = np.asarray(list(range(0, num_pnts)), dtype=int)
"""
Offset is an array that contains the indices of the first point of
each line. The indices start from 0 and given the known geometry of
this actor the creation of this array requires a 2 points padding
between indices.
"""
offset = np.asarray(list(range(0, num_pnts + 1, points_per_line)),
dtype=int)
vtk_array_type = numpy_support.get_vtk_array_type(connectivity.dtype)
cell_array.SetData(
numpy_support.numpy_to_vtk(offset,
deep=True,
array_type=vtk_array_type),
numpy_support.numpy_to_vtk(connectivity,
deep=True,
array_type=vtk_array_type))
else:
connectivity = np.array([], dtype=int)
i_pos = 0
while i_pos < num_pnts:
e_pos = i_pos + points_per_line
"""
In old versions of VTK (<9.0) the connectivity array should include
the length of each line and immediately after the indices of the
points in each line.
"""
connectivity = np.append(connectivity,
[points_per_line, i_pos, e_pos - 1])
i_pos = e_pos
cell_array.GetData().DeepCopy(numpy_support.numpy_to_vtk(connectivity))
cell_array.SetNumberOfCells(num_cells)
return cell_array