"""Miscellaneous functions and classes that dont fit into specificcategories."""import sys, os, vtk#----------------------------------------------------------------------# the following functions are for the vtk regression testing and examplesdef vtkGetDataRoot():    """vtkGetDataRoot() -- return vtk example data directory    """    dataIndex=-1;    for i in range(0, len(sys.argv)):        if sys.argv[i] == '-D' and i < len(sys.argv)-1:            dataIndex = i+1    if dataIndex != -1:        dataRoot = sys.argv[dataIndex]    else:        try:            dataRoot = os.environ['VTK_DATA_ROOT']        except KeyError:            dataRoot = '../../../../VTKData'    return dataRootdef vtkRegressionTestImage( renWin ):    """vtkRegressionTestImage(renWin) -- produce regression image for window    This function writes out a regression .png file for a vtkWindow.    Does anyone involved in testing care to elaborate?    """    dl = vtk.vtkDebugLeaks()    dl.PromptUserOff()    imageIndex=-1;    for i in range(0, len(sys.argv)):        if sys.argv[i] == '-V' and i < len(sys.argv)-1:            imageIndex = i+1    if imageIndex != -1:        fname = os.path.join(vtkGetDataRoot(), sys.argv[imageIndex])        rt_w2if = vtk.vtkWindowToImageFilter()        rt_w2if.SetInput(renWin)        if os.path.isfile(fname):            pass        else:            rt_pngw = vtk.vtkPNGWriter()            rt_pngw.SetFileName(fname)            rt_pngw.SetInput(rt_w2if.GetOutput())            rt_pngw.Write()            rt_pngw = None        rt_png = vtk.vtkPNGReader()        rt_png.SetFileName(fname)        rt_id = vtk.vtkImageDifference()        rt_id.SetInput(rt_w2if.GetOutput())        rt_id.SetImage(rt_png.GetOutput())        rt_id.Update()        if rt_id.GetThresholdedError() <= 10:            return 1        else:            sys.stderr.write('Failed image test: %f\n'                             % rt_id.GetThresholdedError())            return 0    return 2