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""" |
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@author: John NGUI |
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""" |
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|
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import vtk |
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|
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class Transform: |
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""" |
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Class that defines the orientation of planes. |
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|
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@attention: There is a difference between performing rotation first |
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followed by translation, and performing translation first followed |
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by rotation. |
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|
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@attention: VTK's coordinate system and translation is NOT 100% accurate. |
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Consequently, performing maximum rotation and translation can potentially |
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yield incorrect results. For instance, rotating a XY plane along the x-axis |
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90 degrees may NOT produce any results (as it is possible that the XY |
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plane has just fallen outside the visible range). However, rotating the |
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XY plane 89.9 degrees instead should produce the correct resutls. |
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""" |
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|
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def __init__(self): |
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""" |
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Initialise the transform object. |
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""" |
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|
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# NOTE: VTK's coordinates are not 100% accurate. The origin is not |
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# exaclty (0,0,0) and the normal is not exactly (0, 0, 1). There is a |
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# slight variance. As a result, a slight alteration has to be done |
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# in order for the plane to be displayed correctly. Otherwise, the |
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# plane may just fall outside the bounding box and nothing |
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# is displayed. |
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self.__OFFSET_VARIANCE = 0.0000000001 |
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self.__vtk_transform = vtk.vtkTransform() |
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|
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def translate(self, x_offset, y_offset, z_offset): |
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""" |
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Translate the rendered object along the x, y and z-axes. |
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|
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@type x_offset: Number |
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@param x_offset: Amount to translate along the x-axis |
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@type y_offset: Number |
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@param y_offset: Amount to translate along the y-axis |
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@type z_offset: Number |
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@param z_offset: Amount to translate along the z-axis |
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""" |
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|
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self.__vtk_transform.Translate(-x_offset, -y_offset, -z_offset) |
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|
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def rotateX(self, angle): |
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""" |
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Rotate the plane along the x-axis. |
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|
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@type angle: Number |
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@param angle: Angle to rotate the plane |
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""" |
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|
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self.__vtk_transform.RotateX(-angle) |
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|
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def rotateY(self, angle): |
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""" |
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Rotate the plane along the y-axis. |
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|
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@type angle: Number |
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@param angle: Angle to rotate the plane |
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""" |
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|
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self.__vtk_transform.RotateY(angle) |
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|
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def rotateZ(self, angle): |
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""" |
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Rotate the plane along the z-axis. |
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|
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@type angle: Number |
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@param angle: Angle to rotate the plane |
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""" |
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|
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self.__vtk_transform.RotateZ(angle) |
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|
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def setPlaneToXY(self, offset = 0): |
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""" |
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Set the plane orthogonal to the z-axis. |
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|
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@type offset: Number |
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@param offset: Amount to translate along the z-axis |
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""" |
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|
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self.translate(0, 0, offset + self.__OFFSET_VARIANCE) |
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|
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def setPlaneToYZ(self, offset = 0): |
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""" |
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Set the plane orthogonal to the x-axis. |
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|
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@type offset: Number |
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@param offset: Amount to translate along the x-axis |
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""" |
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|
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# NOTE: rotateY must come first before translate. Otherwise, |
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# the output may be incorrect. |
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self.rotateY(90) |
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self.translate(offset, 0, 0) |
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|
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def setPlaneToXZ(self, offset = 0): |
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""" |
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Set the plane orthogonal to the y-axis. |
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|
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@type offset: Number |
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@param offset: Amount to translate along the y-axis |
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""" |
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|
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# rotateX must come first before translate. Otherwise, it won't work. |
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self.rotateX(90) |
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self.translate(0, offset, 0) |
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|
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def _getTransform(self): |
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""" |
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Return the transform instance. |
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|
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@rtype: vtkTransform |
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@return: Transform instance that is used to specify the orientation |
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of the plane |
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""" |
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|
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return self.__vtk_transform |
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|
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|
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############################################################################### |
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|
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|
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class TransformFilter: |
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""" |
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Class that defines a transform poly data filter. |
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""" |
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|
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def __init__(self): |
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""" |
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Initialise the transoform poly data filter. |
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""" |
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|
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self.__vtk_transform_filter = vtk.vtkTransformPolyDataFilter() |
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|
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def _setupTransformFilter(self, plane_source, transform): |
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""" |
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Setup the transform filter. |
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|
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@type plane_source: vtkPolyData |
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@param plane_source: Polygonal data |
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@type transform: L{Transform <transform.Transform>} object |
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@param transform: Specifies the orientation of the plane source |
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""" |
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|
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self.__plane_source = plane_source |
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self.__transform = transform |
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|
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self.__setInput() |
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self.__setTransform() |
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|
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def __setInput(self): |
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""" |
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Set the input for the transform poly data filter. |
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""" |
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|
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self.__vtk_transform_filter.SetInput(self.__plane_source) |
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|
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def __setTransform(self): |
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""" |
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Set the transformation of the plane source. |
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""" |
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|
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self.__vtk_transform_filter.SetTransform(self.__transform) |
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|
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def _getTransformFilterOutput(self): |
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""" |
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Return the output of the transform poly data filter. |
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""" |
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return self.__vtk_transform_filter.GetOutput() |
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