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#!/usr/bin/env python
from vtkmodules.vtkCommonCore import (
vtkDoubleArray,
vtkPoints,
)
from vtkmodules.vtkCommonDataModel import (
vtkCellArray,
vtkPolyData,
)
from vtkmodules.vtkFiltersCore import vtkExtractEdges
from vtkmodules.vtkFiltersModeling import vtkBandedPolyDataContourFilter
from vtkmodules.vtkRenderingCore import (
vtkActor,
vtkPolyDataMapper,
vtkRenderWindow,
vtkRenderWindowInteractor,
vtkRenderer,
)
import vtkmodules.vtkInteractionStyle
import vtkmodules.vtkRenderingFreeType
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.util.misc import vtkGetDataRoot
VTK_DATA_ROOT = vtkGetDataRoot()
# This test reproduces an issue with vtkBandedPolyDataContourFilter
# showing anomalous spikes from edges at which the difference between
# end point scalar values is in the order of the internal tolerance
# value.
#
# The ClipEdge method interpolates between two edge points, creating
# extra points at the clip values. The method finds the iterators
# b and e into the clip values vector for the edge points.
# The clip value for the highest scalar value may be larger than the
# end point scalar value. When the difference between the end point
# values is very small this results in an interpolation factor
# significantly larger than 1.
#
# The effect of this is that spikes appear extending
# outside the original cell.
# Scalars for contouring
values = [
-10.0, -5e-6, -1e-6,
-10.0, -7e-6, -1e-6,
]
def generatePoly(scalars):
"""
Generate two quads and assign scalars
3--4--5
| | |
0--1--2
"""
pts = vtkPoints()
nx=3
ny=int(len(scalars)/nx)
for y in range(0,ny):
for x in range(0,nx):
pts.InsertNextPoint(x,y,0)
connectivity=[(0,1,4,3),(1,2,5,4)]
quads = vtkCellArray()
for quad in connectivity:
quads.InsertNextCell(4,quad)
poly = vtkPolyData()
poly.SetPoints(pts)
poly.SetPolys(quads)
array=vtkDoubleArray()
for s in scalars:
array.InsertNextValue(s)
poly.GetPointData().SetScalars(array)
return poly
def showBandedContours(poly,values,num):
""" Generate banded contours """
high=max(values)
low=min(values)
bpdcf = vtkBandedPolyDataContourFilter()
bpdcf.GenerateContourEdgesOn()
bpdcf.SetScalarModeToValue()
bpdcf.SetInputData(poly)
bpdcf.GenerateValues(num,low,high)
# The clip tolerance specifies a fraction of the scalar range
# It is adjusted to reproduce the issue described
bpdcf.SetClipTolerance(1e-6)
bpdcf.SetScalarModeToIndex()
#internalTol=bpdcf.GetClipTolerance()*(high-low)
#print("internal clip tolerance={}".format(internalTol))
m = vtkPolyDataMapper()
m.SetInputConnection(bpdcf.GetOutputPort())
m.SetScalarModeToUseCellData()
m.SetScalarRange(0,num-1)
bands = vtkActor()
bands.SetMapper(m)
m = vtkPolyDataMapper()
m.SetInputConnection(bpdcf.GetOutputPort(1))
m.ScalarVisibilityOff()
edges = vtkActor()
edges.GetProperty().SetColor(.4,.4,.4)
edges.SetMapper(m)
return bands,edges
def showPolyDataEdges(poly):
edges=vtkExtractEdges()
edges.SetInputDataObject(0,poly)
m = vtkPolyDataMapper()
m.SetInputConnection(edges.GetOutputPort())
m.ScalarVisibilityOff()
a = vtkActor()
a.GetProperty().SetColor(1,1,1)
a.GetProperty().EdgeVisibilityOn()
a.GetProperty().RenderLinesAsTubesOn()
a.SetMapper(m)
return a
poly=generatePoly(values)
inbounds=poly.GetBounds()
bands,edges = showBandedContours(poly,values,6)
bands.GetMapper().Update()
# The bounds of the output of vtkBandedPolyDataContourFilter
# are expected not to exceed those of its input
outbounds=bands.GetMapper().GetInputDataObject(0,0).GetBounds()
error=0
if (inbounds[0] > outbounds[0] or
inbounds[1] < outbounds[1] or
inbounds[2] > outbounds[2] or
inbounds[3] < outbounds[3] or
inbounds[4] > outbounds[4] or
inbounds[5] < outbounds[5]):
print("Output bounds exceed input bounds")
print("input bounds={}".format(inbounds))
print("output bounds={}".format(outbounds))
error=1
ren = vtkRenderer()
ren.AddViewProp( bands )
ren.AddViewProp( edges )
ren.AddViewProp( showPolyDataEdges(poly) )
ren.SetBackground(.6,.6,.6)
renWin = vtkRenderWindow()
renWin.AddRenderer( ren )
ren.GetActiveCamera().SetFocalPoint(1,.5,0)
ren.GetActiveCamera().SetPosition(1,.5,5)
ren.GetActiveCamera().SetViewUp(0,1,0)
iren = vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
iren.Start()
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