
  clip (buffer) [min Vmin max Vmax] [-inf val] [-nan val]

  clip values in an image.  A min/max clip can be applied, 
  in which case all values above max are set to Vmax and all
  below min are set to Vmin.  -nan and -inf flags will set all 
  instances of NaN or any non-finite values to the given value.

