Difference        468 magick/composite.c     composite->red=gamma*Difference(p->red,Sa,q->red,Da);
Difference        469 magick/composite.c     composite->green=gamma*Difference(p->green,Sa,q->green,Da);
Difference        470 magick/composite.c     composite->blue=gamma*Difference(p->blue,Sa,q->blue,Da);
Difference        472 magick/composite.c       composite->index=gamma*Difference(p->index,Sa,q->index,Da);