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"""
vtkImageExportToArray - a NumPy front-end to vtkImageExport
This class converts a VTK image to a Numeric Python array.
To use this class, you must have the LLNL Numeric Python distribution
(http://numpy.sf.net)
Methods
SetInput(input) -- connect to VTK image pipeline
GetArray() -- execute pipeline and return a Numeric array
Convert VTK_UNSIGNED_SHORT to python Int
(this might be necessary because Python doesn't support unsigned short,
the default is to cast unsigned short to signed short).
SetConvertUnsignedShortToInt(yesno)
ConvertUnsignedShortToIntOn()
ConvertUnsignedShortToIntOff()
From vtkImageExport
GetDataExtent()
GetDataSpacing()
GetDataOrigin()
"""
import Numeric
import umath
from vtk import vtkImageExport
from vtkConstants import *
_NEW_NUMERIC = 0
try:
val = float(Numeric.__version__)
except ValueError:
_NEW_NUMERIC = 0
else:
if val > 20.0:
_NEW_NUMERIC = 1
else:
_NEW_NUMERIC = 0
class vtkImageExportToArray:
def __init__(self):
self.__export = vtkImageExport()
self.__ConvertUnsignedShortToInt = 0
# type dictionary: note that python doesn't support
# unsigned integers!
__typeDict = { VTK_CHAR:Numeric.Int8,
VTK_UNSIGNED_CHAR:Numeric.UnsignedInt8,
VTK_SHORT:Numeric.Int16,
VTK_UNSIGNED_SHORT:Numeric.Int16,
VTK_INT:Numeric.Int32,
VTK_FLOAT:Numeric.Float32,
VTK_DOUBLE:Numeric.Float64 }
__sizeDict = { VTK_CHAR:1,
VTK_UNSIGNED_CHAR:1,
VTK_SHORT:2,
VTK_UNSIGNED_SHORT:2,
VTK_INT:4,
VTK_FLOAT:4,
VTK_DOUBLE:8 }
# convert unsigned shorts to ints, to avoid sign problems
def SetConvertUnsignedShortToInt(self,yesno):
self.__ConvertUnsignedShortToInt = yesno
def GetConvertUnsignedShortToInt(self):
return self.__ConvertUnsignedShortToInt
def ConvertUnsignedShortToIntOn(self):
self.__ConvertUnsignedShortToInt = 1
def ConvertUnsignedShortToIntOff(self):
self.__ConvertUnsignedShortToInt = 0
# set the input
def SetInput(self,input):
return self.__export.SetInput(input)
def GetInput(self):
return self.__export.GetInput()
def GetArray(self):
input = self.__export.GetInput()
input.UpdateInformation()
type = input.GetScalarType()
extent = input.GetWholeExtent()
numComponents = input.GetNumberOfScalarComponents()
dim = (extent[5]-extent[4]+1,
extent[3]-extent[2]+1,
extent[1]-extent[0]+1)
if (numComponents > 1):
dim = dim + (numComponents,)
size = dim[0]*dim[1]*dim[2]*numComponents*self.__sizeDict[type]
if _NEW_NUMERIC:
imArray = Numeric.zeros((size,),Numeric.UnsignedInt8)
self.__export.Export(imArray)
else:
imString = Numeric.zeros((size,),
Numeric.UnsignedInt8).tostring()
self.__export.Export(imString)
imArray = Numeric.fromstring(imString,self.__typeDict[type])
# just to remind myself of the dangers of memory management
del imString
# reshape array appropriately.
imArray = Numeric.reshape(imArray, dim)
# convert unsigned short to int to avoid sign issues
if (type == VTK_UNSIGNED_SHORT and self.__ConvertUnsignedShortToInt):
imArray = umath.bitwise_and(imArray.astype(Numeric.Int32),0xffff)
return imArray
def GetDataExtent(self):
return self.__export.GetDataExtent()
def GetDataSpacing(self):
return self.__export.GetDataSpacing()
def GetDataOrigin(self):
return self.__export.GetDataOrigin()
|
