SubtractEvaluateOperator  406 Magick++/lib/Magick++/Include.h   using MagickCore::SubtractEvaluateOperator;
SubtractEvaluateOperator 1012 magick/option.c     { "Subtract", SubtractEvaluateOperator, UndefinedOptionFlag, MagickFalse },
SubtractEvaluateOperator  372 magick/statistic.c     case SubtractEvaluateOperator: