/[escript]/trunk/pyvisi/py_src/streamlinemodule.py
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Contents of /trunk/pyvisi/py_src/streamlinemodule.py

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Revision 1147 - (show annotations)
Wed May 16 06:39:11 2007 UTC (13 years, 11 months ago) by ksteube
File MIME type: text/x-python
File size: 3729 byte(s)
Added back in some files that were accidentally deleted.

1 """
2 @author: John NGUI
3 """
4
5 import vtk
6
7 class StreamLineModule:
8 """
9 Class that defines the streamline module.
10 """
11
12 def __init__(self, object, source):
13 """
14 Initialise the streamline module.
15
16 @type object: vtkUnstructuredGrid, etc
17 @param object: Input for the streamline
18 @type source: vtkPolyData
19 @param source: Source to generate the starting points
20 """
21
22 self.__object = object
23 self.__source = source
24 self.__vtk_stream_line = vtk.vtkStreamLine()
25
26 self.__setupStreamLineModule()
27
28 def __setupStreamLineModule(self):
29 """
30 Setup the streamline.
31 """
32
33 self.__setInput()
34 self.__setSource()
35 # Default maximum propagation time is 100.
36 self.setMaximumPropagationTime(100)
37 # Default step length is 0.01
38 self.setStepLength(0.01)
39 # Default integration step length is 0.01
40 self.setIntegrationStepLength(0.01)
41 # Default integration is set to both directions.
42 self.setIntegrationToBothDirections()
43 # Default integrator is set to vtkRungeKutta4
44 self.setIntegrator(vtk.vtkRungeKutta4())
45 self.__vtk_stream_line.Update()
46
47 def __setInput(self):
48 """
49 Set the input for the streamline.
50 """
51
52 self.__vtk_stream_line.SetInput(self.__object)
53
54 def __setSource(self):
55 """
56 Set the source to generate the starting points for the streamline.
57 """
58
59 self.__vtk_stream_line.SetSource(self.__source)
60
61 def setMaximumPropagationTime(self, time):
62 """
63 Set the maximum length of the streamline expressed in elapsed time.
64
65 @type time: Number
66 @param time: Maximum length of the streamline expressed in elapsed time
67 """
68
69 self.__vtk_stream_line.SetMaximumPropagationTime(time)
70
71 def setStepLength(self, length):
72 """
73 Set the length of the streamline segment expressed in elapsed time.
74 A smaller value results in a smoother streamline
75 (but is more expensive). Setting the step length usually goes
76 hand-in-hand with setting the integration step length. Otherwise,
77 errors such as "... can't compute normals" may arise. If such an
78 error occurs try changing the value. However, it does not usually
79 apply the other way around.
80
81 @type length: Number
82 @param length: Length of the streamline segment expressed in
83 elapsed time
84 """
85
86 self.__vtk_stream_line.SetStepLength(length)
87
88 def setIntegrationStepLength(self, length):
89 """
90 Set the integration step size expressed as a fraction of the size of
91 each cell. A smaller length results in a better image (but is more
92 expensive).
93
94 @type length: Number
95 @param length: Length of the integration step expressed as a fraction
96 of the size of each cell
97 """
98
99 self.__vtk_stream_line.SetIntegrationStepLength(length)
100
101 def setIntegrationToBothDirections(self):
102 """
103 Set the integration to occur both sides: forward (where the streamline
104 goes) and backward (where the streamline came from).
105 """
106
107 self.__vtk_stream_line.SetIntegrationDirectionToIntegrateBothDirections()
108
109 def setIntegrator(self, integrator):
110 """
111 Set the integrator to be used in the streamline calculation.
112
113 @type integrator: vtkInitialValueProblemSolver
114 @param integrator: Integrator type. i.e. vtkRungeKutta2, vtkRungeKutta4
115 """
116
117 self.__vtk_stream_line.SetIntegrator(integrator)
118
119 def _setSpeedScalarsOn(self):
120 """
121 Turn on the creation of scalar data from velocity magnitude.
122 """
123
124 self.__vtk_stream_line.SpeedScalarsOn()
125
126 def _setSpeedScalarsOff(self):
127 """
128 Turn off the creation of scalar data from velocity magnitude. If
129 input dataset has scalars, input dataset scalars are used.
130 """
131
132 self.__vtk_stream_line.SpeedScalarsOff()
133
134 def _getOutput(self):
135 """
136 Return the output of the streamline.
137
138 @rtype: vtkPolyData
139 @return Polygonal data
140 """
141
142 return self.__vtk_stream_line.GetOutput()

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