| 1 |
""" |
| 2 |
@author: John NGUI |
| 3 |
""" |
| 4 |
|
| 5 |
import vtk |
| 6 |
|
| 7 |
class Transform: |
| 8 |
""" |
| 9 |
Class that defines the orientation of planes. |
| 10 |
|
| 11 |
@attention: There is a difference between performing rotation first |
| 12 |
followed by translation, and performing translation first followed |
| 13 |
by rotation. |
| 14 |
|
| 15 |
@attention: VTK's coordinate system and translation is NOT 100% accurate. |
| 16 |
Consequently, performing maximum rotation and translation can potentially |
| 17 |
yield incorrect results. For instance, rotating a XY plane along the x-axis |
| 18 |
90 degrees may NOT produce any results (as it is possible that the XY |
| 19 |
plane has just fallen outside the visible range). However, rotating the |
| 20 |
XY plane 89.9 degrees instead should produce the correct resutls. |
| 21 |
""" |
| 22 |
|
| 23 |
def __init__(self): |
| 24 |
""" |
| 25 |
Initialise the transform object. |
| 26 |
""" |
| 27 |
|
| 28 |
# NOTE: VTK's coordinates are not 100% accurate. The origin is not |
| 29 |
# exaclty (0,0,0) and the normal is not exactly (0, 0, 1). There is a |
| 30 |
# slight variance. As a result, a slight alteration has to be done |
| 31 |
# in order for the plane to be displayed correctly. Otherwise, the |
| 32 |
# plane may just fall outside the bounding box and nothing |
| 33 |
# is displayed. |
| 34 |
self.__OFFSET_VARIANCE = 0.0000000001 |
| 35 |
self.__vtk_transform = vtk.vtkTransform() |
| 36 |
|
| 37 |
def translate(self, x_offset, y_offset, z_offset): |
| 38 |
""" |
| 39 |
Translate the rendered object along the x, y and z-axes. |
| 40 |
|
| 41 |
@type x_offset: Number |
| 42 |
@param x_offset: Amount to translate along the x-axis |
| 43 |
@type y_offset: Number |
| 44 |
@param y_offset: Amount to translate along the y-axis |
| 45 |
@type z_offset: Number |
| 46 |
@param z_offset: Amount to translate along the z-axis |
| 47 |
""" |
| 48 |
|
| 49 |
self.__vtk_transform.Translate(-x_offset, -y_offset, -z_offset) |
| 50 |
|
| 51 |
def rotateX(self, angle): |
| 52 |
""" |
| 53 |
Rotate the plane along the x-axis. |
| 54 |
|
| 55 |
@type angle: Number |
| 56 |
@param angle: Angle to rotate the plane |
| 57 |
""" |
| 58 |
|
| 59 |
self.__vtk_transform.RotateX(-angle) |
| 60 |
|
| 61 |
def rotateY(self, angle): |
| 62 |
""" |
| 63 |
Rotate the plane along the y-axis. |
| 64 |
|
| 65 |
@type angle: Number |
| 66 |
@param angle: Angle to rotate the plane |
| 67 |
""" |
| 68 |
|
| 69 |
self.__vtk_transform.RotateY(angle) |
| 70 |
|
| 71 |
|
| 72 |
def rotateZ(self, angle): |
| 73 |
""" |
| 74 |
Rotate the plane along the z-axis. |
| 75 |
|
| 76 |
@type angle: Number |
| 77 |
@param angle: Angle to rotate the plane |
| 78 |
""" |
| 79 |
|
| 80 |
self.__vtk_transform.RotateZ(angle) |
| 81 |
|
| 82 |
def setPlaneToXY(self, offset = 0): |
| 83 |
""" |
| 84 |
Set the plane orthogonal to the z-axis. |
| 85 |
|
| 86 |
@type offset: Number |
| 87 |
@param offset: Amount to translate along the z-axis |
| 88 |
""" |
| 89 |
|
| 90 |
self.translate(0, 0, offset + self.__OFFSET_VARIANCE) |
| 91 |
|
| 92 |
def setPlaneToYZ(self, offset = 0): |
| 93 |
""" |
| 94 |
Set the plane orthogonal to the x-axis. |
| 95 |
|
| 96 |
@type offset: Number |
| 97 |
@param offset: Amount to translate along the x-axis |
| 98 |
""" |
| 99 |
|
| 100 |
# NOTE: rotateY must come first before translate. Otherwise, |
| 101 |
# the output may be incorrect. |
| 102 |
self.rotateY(90) |
| 103 |
self.translate(offset, 0, 0) |
| 104 |
|
| 105 |
def setPlaneToXZ(self, offset = 0): |
| 106 |
""" |
| 107 |
Set the plane orthogonal to the y-axis. |
| 108 |
|
| 109 |
@type offset: Number |
| 110 |
@param offset: Amount to translate along the y-axis |
| 111 |
""" |
| 112 |
|
| 113 |
# rotateX must come first before translate. Otherwise, it won't work. |
| 114 |
self.rotateX(90) |
| 115 |
self.translate(0, offset, 0) |
| 116 |
|
| 117 |
def _getTransform(self): |
| 118 |
""" |
| 119 |
Return the transform instance. |
| 120 |
|
| 121 |
@rtype: vtkTransform |
| 122 |
@return: Transform instance that is used to specify the orientation |
| 123 |
of the plane |
| 124 |
""" |
| 125 |
|
| 126 |
return self.__vtk_transform |
| 127 |
|
| 128 |
|
| 129 |
############################################################################### |
| 130 |
|
| 131 |
|
| 132 |
class TransformFilter: |
| 133 |
""" |
| 134 |
Class that defines a transform poly data filter. |
| 135 |
""" |
| 136 |
|
| 137 |
def __init__(self, plane_source, transform): |
| 138 |
""" |
| 139 |
Initialise the transoform poly data filter. |
| 140 |
|
| 141 |
@type plane_source: vtkPolyData |
| 142 |
@param plane_source: Polygonal data |
| 143 |
@type transform: L{Transform <transform.Transform>} object |
| 144 |
@param transform: Specifies the orientation of the plane source |
| 145 |
""" |
| 146 |
|
| 147 |
self.__plane_source = plane_source |
| 148 |
self.__transform = transform |
| 149 |
|
| 150 |
self.__vtk_transform_filter = vtk.vtkTransformPolyDataFilter() |
| 151 |
|
| 152 |
self._setInput() |
| 153 |
self._setTransform() |
| 154 |
|
| 155 |
def _setInput(self): |
| 156 |
""" |
| 157 |
Set the input for the transform poly data filter. |
| 158 |
""" |
| 159 |
|
| 160 |
self.__vtk_transform_filter.SetInput(self.__plane_source) |
| 161 |
|
| 162 |
def _setTransform(self): |
| 163 |
""" |
| 164 |
Set the transformation of the plane source. |
| 165 |
""" |
| 166 |
|
| 167 |
self.__vtk_transform_filter.SetTransform(self.__transform) |
| 168 |
|
| 169 |
def _getOutput(self): |
| 170 |
""" |
| 171 |
Return the output of the transform poly data filter. |
| 172 |
""" |
| 173 |
|
| 174 |
return self.__vtk_transform_filter.GetOutput() |
| 175 |
|
| 176 |
|
| 177 |
|
| 178 |
|
| 179 |
|
| 180 |
|
Parent Directory
| 
Revision Log