StippledLine
vtk-examples/Python/Rendering/StippledLine
Description¶
VTK OpenGL2 no longer supports Stippled Lines. This example uses texture mapping to created stippled lines. Two parameters, StipplePattern and StippleRepeat, control the pattern of the stippled lines.
StipplePattern is a 16-bit binary pattern, 1 = pixel on, 0 = pixel off.
StippleRepeat is the stippling repeat factor of a Line, which specifies how many times each bit in the pattern is to be repeated.
It can be tricky to set the proper pattern and repeat, so experiment.
Other languages
See (Cxx)
Question
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Code¶
StippledLine.py
#!/usr/bin/env python
import vtk
def main():
colors = vtk.vtkNamedColors()
lines = vtk.vtkLineSource()
# Create two points, P0 and P1
p0 = [1.0, 0.0, 0.0]
p1 = [5.0, 0.0, 0.0]
lines.SetResolution(11)
lines.SetPoint1(p0)
lines.SetPoint2(p1)
lines.Update()
mapper = vtk.vtkPolyDataMapper()
mapper.SetInputConnection(lines.GetOutputPort())
actor = vtk.vtkActor()
actor.SetMapper(mapper)
actor.GetProperty().SetLineWidth(5)
actor.GetProperty().SetColor(colors.GetColor3d("Banana"))
StippledLine(actor, 0xA1A1, 2)
ren1 = vtk.vtkRenderer()
ren1.SetBackground(colors.GetColor3d("SlateGray"))
renWin = vtk.vtkRenderWindow()
renWin.SetSize(640, 480)
renWin.SetWindowName('StippledLine')
renWin.AddRenderer(ren1)
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)
ren1.AddActor(actor)
renWin.Render()
iren.Start()
def StippledLine(actor, lineStipplePattern, lineStippleRepeat):
tcoords = vtk.vtkDoubleArray()
image = vtk.vtkImageData()
texture = vtk.vtkTexture()
# Create texture
dimension = 16 * lineStippleRepeat
image.SetDimensions(dimension, 1, 1)
image.AllocateScalars(vtk.VTK_UNSIGNED_CHAR, 4)
image.SetExtent(0, dimension - 1, 0, 0, 0, 0)
on = 255
off = 0
i_dim = 0
while i_dim < dimension:
for i in range(0, 16):
mask = (1 << i)
bit = (lineStipplePattern & mask) >> i
value = bit
if value == 0:
for j in range(0, lineStippleRepeat):
image.SetScalarComponentFromFloat(i_dim, 0, 0, 0, on)
image.SetScalarComponentFromFloat(i_dim, 0, 0, 1, on)
image.SetScalarComponentFromFloat(i_dim, 0, 0, 2, on)
image.SetScalarComponentFromFloat(i_dim, 0, 0, 3, off)
i_dim += 1
else:
for j in range(0, lineStippleRepeat):
image.SetScalarComponentFromFloat(i_dim, 0, 0, 0, on)
image.SetScalarComponentFromFloat(i_dim, 0, 0, 1, on)
image.SetScalarComponentFromFloat(i_dim, 0, 0, 2, on)
image.SetScalarComponentFromFloat(i_dim, 0, 0, 3, on)
i_dim += 1
polyData = actor.GetMapper().GetInput()
# Create texture coordinates
tcoords.SetNumberOfComponents(1)
tcoords.SetNumberOfTuples(polyData.GetNumberOfPoints())
for i in range(0, polyData.GetNumberOfPoints()):
value = i * 0.5
tcoords.SetTypedTuple(i, [value])
polyData.GetPointData().SetTCoords(tcoords)
texture.SetInputData(image)
texture.InterpolateOff()
texture.RepeatOn()
actor.SetTexture(texture)
if __name__ == '__main__':
main()