Convert VTK built-in types to SimpleITK/ITK built-ins and vice-versa #python #vtk #simpleitk #itk

builtin_type_convert_vtk_simpleitk.md

We start by importing vtk and SimpleITK:

import vtk
import SimpleITK

We then create two dictionaries containing the matching built-in types:

dctITKtoVTK = {SimpleITK.sitkInt8: vtk.VTK_TYPE_INT8,
               SimpleITK.sitkInt16: vtk.VTK_TYPE_INT16,
               SimpleITK.sitkInt32: vtk.VTK_TYPE_INT32,
               SimpleITK.sitkInt64: vtk.VTK_TYPE_INT64,
               SimpleITK.sitkUInt8: vtk.VTK_TYPE_UINT8,
               SimpleITK.sitkUInt16: vtk.VTK_TYPE_UINT16,
               SimpleITK.sitkUInt32: vtk.VTK_TYPE_UINT32,
               SimpleITK.sitkUInt64: vtk.VTK_TYPE_UINT64,
               SimpleITK.sitkFloat32: vtk.VTK_TYPE_FLOAT32,
               SimpleITK.sitkFloat64: vtk.VTK_TYPE_FLOAT64}
dctVTKtoITK = dict(zip(dctITKtoVTK.values(), 
                       dctITKtoVTK.keys()))

These two next functions can then use the above dictionaries to easily convert between matching types:

def convertTypeITKtoVTK(typeITK):
    if typeITK in dctITKtoVTK:
        return dctITKtoVTK[typeITK]
    else:
        raise ValueError("Type not supported")

def convertTypeVTKtoITK(typeVTK):
    if typeVTK in dctVTKtoITK:
        return dctVTKtoITK[typeVTK]
    else:
        raise ValueError("Type not supported")

The entirety of the code can be seen in the accompanying .py file

builtin_type_convert_vtk_simpleitk.py

import vtk
import SimpleITK

dctITKtoVTK = {SimpleITK.sitkInt8: vtk.VTK_TYPE_INT8,
               SimpleITK.sitkInt16: vtk.VTK_TYPE_INT16,
               SimpleITK.sitkInt32: vtk.VTK_TYPE_INT32,
               SimpleITK.sitkInt64: vtk.VTK_TYPE_INT64,
               SimpleITK.sitkUInt8: vtk.VTK_TYPE_UINT8,
               SimpleITK.sitkUInt16: vtk.VTK_TYPE_UINT16,
               SimpleITK.sitkUInt32: vtk.VTK_TYPE_UINT32,
               SimpleITK.sitkUInt64: vtk.VTK_TYPE_UINT64,
               SimpleITK.sitkFloat32: vtk.VTK_TYPE_FLOAT32,
               SimpleITK.sitkFloat64: vtk.VTK_TYPE_FLOAT64}
dctVTKtoITK = dict(zip(dctITKtoVTK.values(), 
                       dctITKtoVTK.keys()))
                       
def convertTypeITKtoVTK(typeITK):
    if typeITK in dctITKtoVTK:
        return dctITKtoVTK[typeITK]
    else:
        raise ValueError("Type not supported")

def convertTypeVTKtoITK(typeVTK):
    if typeVTK in dctVTKtoITK:
        return dctVTKtoITK[typeVTK]
    else:
        raise ValueError("Type not supported")