[vtkusers] Inverting image data

[dean.inglis at on.aibn.com]

Steve,

here is a bit of tcl script I used for
inverting image data, the key is the
vtkImageShiftScale filter with which
you can set the output scalar type to 
whatever you need:

vtkImageReader v16
  v16 SetFileName "mydata.dat"
  v16 SetDataScalarTypeToUnsignedShort 
  v16 SetDataByteOrderToLittleEndian 
  v16 SetFileDimensionality 3 
  v16 FileLowerLeftOff 
  v16 SetDataOrigin 0 0 0 
  v16 SetDataExtent 0 66 0 66 0 11 
  v16 SetDataSpacing .1953125 .1953125 0.8
  v16 ReleaseDataFlagOn
  v16 Update
  set tmp [[v16 GetOutput] GetScalarRange]
  set min [lindex $tmp 0]
  set max [lindex $tmp 1]

vtkImageShiftScale shift 
 shift SetOutputScalarTypeToUnsignedChar
 shift ReleaseDataFlagOn
 shift ClampOverflowOn 
 shift SetScale -1
 shift SetShift [expr -1.0*$max]
 shift SetInput [v16 GetOutput]
 shift Update

hope this helps,
Dean