MagickGetImageChannelMean 2462 TclMagick/generic/TclMagick.c result = MagickGetImageChannelMean(wandPtr, chanTypes[chanIdx], &mean, &deviation); MagickGetImageChannelMean 190 wand/magick_wand.h MagickGetImageChannelMean(MagickWand *,const ChannelType,double *,double *),